Istituto per lo Studio e la PrevenzioneOncologica di Firenze
SSD Unità di Valutazione e Organizzazione Screening, Dipartimento di Prevenzione - Cuneo
Istituto di Ricerche Farmacologiche Mario Negri IRCCS
How it works
UOC Medicina Preventiva delle Comunità – Screening, ATS della Città Metropolitana di Milano
Unità Operativa Centro GestionaleScreening di Palermo
This project is coordinated by Mario Negri Institute for Pharmacological Research IRCCS in collaboration with Lega Italiana Lotta contro i Tumori-Firenze, Zadig Agenzia di Editoria Scientifica, GISMa Gruppo Italiano Screening Mammografico and with Prevenzione Serena di Torino, Unità Operativa Centro Gestionale Screening di Palermo and Istituto per lo Studio e la Prevenzione Oncologica di Firenze.
The project is funded by AIRC, the Italian Association for Cancer Research- IG2015-17274
AITERS - Associazione Italiana Tecnici di Radiologia Senologica (Galli Vania)
Altroconsumo (Caldara Daniele)ANISC - Associazione Nazionale Italiana Senologi Chirurghi (Taffurelli Mario)Associazione La Lampada di Aladino (Petruzzelli Davide)Europa Donna Italia (Sestini Elisabetta)Federazione per il Sociale e la Sanità della Provincia Autonoma di Bolzano e Rete Nord-Est (Zimmermann Paola)IRCCS Istituto Mario Negri (Torri Valter)Servizio di educazione all’appropriatezza e medicina basata sulle evidenze, ASL Città di Milano (Donzelli Alberto)Servizio Sanità Pubblica e Screening, Regione Veneto (Russo Francesca)SIMG - Società Italiana di Medicina Generale e delle cure primarie (Apice Serena)SIRM - Società Italiana Radiologia Medica (Sardanelli Francesco)
Lega Italiana Lotta contro i Tumori - Firenze
Zadig Agenzia di editoria scientifica
Centro Screening Oncologici di Reggio Emilia
GISMa Gruppo Italiano Screening Mammografico
e Prevenzione Serena - Torino
Mediterranean dietDiet typical of the Mediterranean areas, it involves eating fruit, vegetables, whole grains, fish, legumes, nuts, olive oil and moderate amounts of wine.
Vegan dietNutritional model that excludes all foods of animal origin, including dairy products and eggs in favour of vegetables f. Given the extreme selectivity compared to other vegetarian models, it is not balanced and involves a risk of deficiencies in vitamins (such as vitamin B12) and minerals (such as iron).
Alcohol doseAlcohol consumption is usually expressed as the unit of alcohol or "standard glass" which is about 10-12 grams of pure alcohol and corresponds to one glass of wine (12°, 125 mL), a can of beer (4.5°, 330 mL), an aperitif (18°, 80 mL), or a small glass of hard liquor
IncidenceNumber of new cases of a disease diagnosed in a population in one year.
BMI Body Mass Index or IMCThis is calculated by dividing the body weight (in kg) by the square of the height (in meters). For example, for a woman who weighs 60 kilograms and is 1 meter 70 centimetres (1.7 meters) tall, the body mass index is 60/(1.70 * 1.70) = 60 / 2.89 = 20.76 Kg / m2.
This index indicates if a woman is underweight (BMI less than 19), normal weight (BMI between 19 and 24), overweight (BMI between 25 and 30) or obese (BMI more than 30).
The woman in our example is normal weight.
MortalityNumber of deaths with a specific disease (e.g. breast cancer) in a population over a given period.
PrevalenceNumber of subjects with a specific disease (e.g. breast cancer) in a given interval as a proportion of the total number of subjects in the reference population.
Systematic reviewA systematic review is a summary of research evidence (studies) on a certain topic.
The term systematic refers to the fact that the review is planned as a study. It starts with a clearly formulated question, then identify, select, and critically appraise relevant studies finally, collect and analyze data from the studies that are included in the review.
For many people “risk” means “danger” but “risk” is also used to mean the probability of an outcome.
Relative riskThe relative risk is the probability that a subject belonging to a group with certain characteristics (e.g. overweight) develops a certain condition (e.g. breast cancer), compared to the probability of developing the same condition in a group without that characteristic (not overweight). In numbers, the risk of breast cancer for an overweight subject is 30% higher than for a non-overweight woman. The risk of breast cancer for a person who follows the Mediterranean diet is 68% lower than the risk of a person who does not follow it.
Metabolic syndromeA pathological condition presenting of at least three of the following:
• Abdominal fat
• High levels of triglycerides in the blood
• Low "good" cholesterol in the blood (HDL High-Density-Lipoprotein)
• High blood pressure
• High blood sugar, up to type 2 diabetes (non-insulin-dependent diabetes)
People with metabolic syndrome have a high risk of cardiovascular disease and some kinds of cancer.
SurvivalThe proportion of individuals with a certain disease who survive for a given time.
Observational studyIn this study, researchers – without changing clinical practice - follow women who have participated or not participated in mammography screening for years, and record the frequency of various events, such as breast cancer, deaths from the disease, overdiagnosis, etc.
Experimental studyIn these studies researchers change the order of things by introducing an intervention (for example the invitation for mammography screening) and study the effects of the intervention. These studies must provide: an adequate number of people –the sample, a comparison treatment - called "control", and procedures to avoid the effects of factors that can influence and confound the results.
An experimental study can be randomized, meaning the people involved are randomly assigned to one of two groups (intervention and control), as if by tossing a coin. The randomization aims to make the two groups similar in their characteristics and therefore comparable so as to measure the effect of the intervention.
Hormone replacement therapy - HRTTreatment with female hormones (oestrogens and/or progestins) when ovarian function has ceased due to menopause or surgery.
Breast cancerBreast cancer is due to the uncontrolled multiplication of some cells of the mammary gland that became malignant.
For more info: AIRC
How does q.b.
q.s. to know just enough it is a tool that collects useful information to decide whether or not to participate in the organized mammography screening program.
The path is free and you can move through the contents through the links in the text or through the buttons in the left column.On each page at the site map symbol (top right or left column) you will find a navigation map.When you think you have clear ideas and feel ready for your decision, click on the button ready to choose (in the left column) that takes you to a page where the main aspects that can influence your decision are listed. Reading all the content takes about 40 minutes.
WHAT IS MAMMOGRAPHY SCREENING
ORGANIZED MAMMOGRAPHY SCREENING PROGRAM
AT WHAT AGE IS MAMMOGRAPHY SCREENING RECOMMENDED
RISK AND PROTECTIVE FACTORS
COMPARISON OF DOSES OF RADIATION
DIAGNOSTIC PROGRAMS IN UNCERTAIN CASES
PROS AND CONS OF MAMMOGRAPHY SCREENING
THE RISKS RELATED TO RADIATION
DIFFERENT OVERDIAGNOSIS ESTIMATES
WHAT HAPPENS IN THE NEXT 30 YEARS
WHAT RESULT WILL THE MAMMOGRAPHY GIVE
DIFFERENCES BETWEEN FALSE POSITIVES AND OVERDIAGNOSIS
BALANCE BETWEEN BENEFITS AND HARMS
MORTALITY REDUCTION AND OVERDIAGNOSIS MEASURES
WHAT IS BREAST CANCER AND HOW CAN IT BE TREATED ?
DIFFERENT ESTIMATES OF THE REDUCTION OF MORTALITY
WHAT HAPPENS AT EACH SCREENING
The information available in this tool does not replace the information and advice you can have by contacting your doctor directly.
To learn moreHere is a list of information sources that we have selected for the contents of q.b. per sapere quanto basta.At what age is mammography screening recommended?The scientific societies accredited at national and international level:
GISMA (Gruppo Italiano Screening Mammografico):
Distante V, et al; Gruppo Italiano Screening Mammografico (GISMa). Sull’opportunità di estendere lo screening mammografico organizzato alle donne di 40-49 e 70-74 anni di età. Raccomandazioni di una conferenza di consenso italiana. Epidemiol Prev 2007;31:15-22.IARC (Agenzia internazionale per la ricerca sul cancro):
IARC Handbooks of Cancer Prevention. Breast cancer screening. IARC, n. 15, Lyon, 2016.ONS (Osservatorio Nazionale Screening):
Ministero della Salute – Osservatorio Nazionale Screening (ONS). Raccomandazioni per la pianificazione e l’esecuzione degli screening di popolazione per la prevenzione del cancro della mammella, del cancro della cervice uterina e del cancro del colon retto, 2006.The risks related to radiationYaffe MJ, Mainprize JG. Risk of radiation-induced breast cancer from mammographic screening. Radiology 2011;258:98-105.Hauge IH, et al. The risk of radiation-induced breast cancers due to biennial mammographic screening in women aged 50-69 years is minimal. Acta Radiol 2014;55):1174-9.United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Effects and risks of ionizing radiation. New York, 2016. [link]National Council on Radiation Protection and Measurements (NCRP). Ionizing radiation exposure of the population of the United States. Report n. 160. Bethesda, 2009.Ministry of Education, Culture, Sports, Science, and Technology of Japan (MEXT). Radiation in daily life. 2011[link]Comparison of doses of radiation from different examinations in adultsRadiological Society of North America (RSNA) – American College of Radiology (ACR).Dose reference card. Radiation dose to adults from common imaging examinations. [link]Organized mammography screening program, a quality programOsservatorio Nazionale Screening. Undicesimo rapporto, 2015. [link]Lo Screening a Torino. [link]Lo Screening a Firenze. [link]Lo Screening a Palermo. [link]What happens at each screening?EUROSCREEN Working Group. J Med Screen 2012;19(Suppl1).The main risk and protective factorsGeneral information
IARC Handbooks of Cancer Prevention. Breast cancer screening. IARC, n. 15, Lyon, 2014Risk factors in alphabetical order
Alexander DD, et al. A review and meta-analysis of red and processed meat consumption and breast cancer. Nutr Res Rev 2010; 23:349-65.Berrino F, et al. Metabolic syndrome and breast cancer prognosis. Breast Cancer Res Treat 2014;147:159.Bhaskaran K,et al. Body-mass index and risk of 22 specific cancers: a population-based cohort study of 5.24 million UK adults. Lancet 2014;384:755.Esposito K, et al. Metabolic syndrome and risk of cancer: a systematic review and meta-analysis. Diabetes Care 2012;35:2402-11.Farvid MS, et al. Dietary protein sources in early adulthood and breast cancer incidence: prospective cohort study. BMJ 2014;348:g3437Gaudet M, et al. Active smoking and breast cancer risk: original cohort data and meta-analysis. J Natl Cancer Inst 2013; 105:515-25.Jones ME, et al. Menopausal hormone therapy and breast cancer: what is the true size of the increased risk? Br J Cancer 2016; 115:607-15.Lippi G, et al. Meat consumption and cancer risk: a critical review of published meta-analyses. Crit Rev Oncol Hematol 2016;97:1.Liu Y, et al. Alcohol intake between menarche and first pregnancy: a prospective study of breast cancer risk. J Natl Cancer Inst 2013;105:1571-8.Manson JE, et al. Menopausal hormone therapy and health outcomes during the intervention and extended poststopping phases of the Women’s Health Initiative randomized trials. JAMA 2013;310:1353-68.Namiranian N, et al. Risk factors of breast cancer in the Eastern Mediterranean Region: a systematic review and meta-analysis. Asian Pac J Cancer Prev 2014;15, 9535-41.Reeves GK, et al. Hormonal therapy for menopause and breast-cancer risk by histological type: a cohort study and meta-analysis. Lancet Oncology 2006;7:910-8.Schutze M, et al. Alcohol attributable burden of incidence of cancer in eight European countries based on results from prospective cohort study. BMJ 2011;342:d1584.Taylor VH, et al. Is red meat intake a risk factor for breast cancer among premenopausal women? Breast Cancer Res Treat 2009; 117:1-8.Protective factors
Agency for Healthcare Research and Quality US. Breastfeeding and maternal and infant health outcomes in developed countries. Evidence Report/TA n. 153, 2007.Bradbury KE, et al. Fruit, vegetable, and fiber intake in relation to cancer risk: findings from the EPIC. Am J Clin Nutr 2014;100(suppl 1):394S.Farvid MS, et al. Dietary fiber intake in young adults and breast cancer risk. Pediatrics 2016; 137:e20151226.Farvid MS, et al. Fruit and vegetable consumption in adolescence and early adulthood and risk of breast cancer: population based cohort study. BMJ 2016;353:i2343.Hastert TA, et al. Adherence to WCRF/AICR cancer prevention recommendations and risk of postmenopausal breast cancer. Cancer Epidemiol Biomarkers Prev 2013; 22:1498-508.IARC Handbooks of Cancer Prevention. Weight control and physical activity. IARC, n. 6, Lyon, 2002.Kwan ML, et al. Breastfeeding, PAM50 tumor subtype, and breast cancer prognosis and survival. J Natl Cancer Inst 2015;107:djv087.Moore SC, et al. Association of leisure-time physical activity with risk of 26 types of cancer in 1.44 million adults. JAMA Intern Med 2016;176:816.Tantamango-Bartley Y, et al. Vegetarian diets and the incidence of cancer in a low-risk populations. Cancer Epidemiol Biomarkers Prev 2013;22:286-94.Toledo E, et al. Mediterranean diet and invasive breast cancer risk among women at high cardiovascular risk in the PREDIMED trial: a randomized clinical trial. JAMA Intern Med 2015;175:1752-60.WHO Global recommendations on physical activity for health, 2010. [LINK]Different estimates of the reduction of mortality due to breast cancer IARC Handbooks of Cancer Prevention. Breast cancer screening. IARC, n. 15, Lyon, 2014.IARC Handbooks of Cancer Prevention. Breast cancer screening. IARC, n. 7, Lyon, 2002.Puliti D1, Duffy SW, Miccinesi G, de Koning H, Lynge E, Zappa M, Paci E; EUROSCREEN Working Group. Overdiagnosis in mammographic screening for breast cancer in Europe: a literature review. J Med Screen. 2012;19 Suppl 1:42-56.Independent UK Panel on breast cancer screening. The benefits and harms of breast cancer screening: an independent review. Lancet 2012;380:1778-86. Gøtzsche PC, Jørgensen KJ. Screening for breast cancer with mammography. Cochrane Database Syst Rev 2013;6:CD001877.
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This decision aid has been developed within a research project aimed to convey more information about mammography in an organized mammography screening program and increase knowledge and awareness.
According to the Italian Ministry of Health recommendations, based on scientific studies, the use of this test in the screening program can reduce mortality due to breast cancer among women of your age.
Obviously, the decision to participate or not is entirely up to you.
Here you will find some up-to-date information about mammography screening, its pros and cons, including the controversies and different opinions of experts.
We know that your choice will not be based only on this information but other aspects too will affect the decision: your life experience, your perception of the risk of developing this disease and your own values. These are very important aspects that drive many of our choices: they shall therefore recall at the end of the navigation when you make your final decision.
Before taking a decision, explore these pages, in your own time: the icon at the top sitemap will help you navigate.
| MAMMOGRAPHIC SCREENING
Organized mammography screening program, a quality program
In the organized mammography screening program, all women of your age are regularly invited for a free mammography at a clinical center involved in the program that guarantees full assistance, for diagnosis and treatment of any breast cancer.
The quality of all Italian organized mammography screening programs, including the one you are invited to, is monitored and evaluated within national and international initiatives (see the sources above and on the right). Outside this program there is no way of judging, as there is no regular data collection.
At your appointment, a radiographer will take two X-rays for each breast from different angles. The breast is pressed between two plastic plates and this may cause slight discomfort. However, the stronger compression the less radiation you will receive and the more accurate will be the exam.
The X-rays are then assessed by two expert medical radiologists who read at least 5000 exams a year as a quality standard.
If all is well, you will receive a letter or an e-mail. If there is any doubt you will be contacted by phone.
• Inconvenience of the examination
• Less invasive treatments
• Reduction of mortality due to breast
• Radiation damage
• False positives or false negatives
The pros and cons of mammography screening
Mammography screening can provide both benefits and harms, like any other medical examination.
Mammography does not prevent breast cancer but it helps find tumors in an early stage when there is less invasive and more effective treatment.
The main advantage is the reduction of mortality due to breast cancer for women who participate in the organized screening program.
The principal disadvantage is harder to grasp. Sometimes there is unnecessary and useless treatment (overtreatment), and if it is useless it is harmful, of tumors discovered by the screening that would resolve themselves spontaneously during the woman’s life (overdiagnosis). These malignancies look just like other tumors but either do not grow or grow very slowly. Unfortunately, so far there is no way to distinguish whether a tumor is actually not harmful, so all cases are treated and the woman will not know what her situation was.
It is only possible to estimate the reduction of mortality due to breast cancer by the mammography screening program, and of extra tumor diagnosis (overdiagnosis).
Participation in the screening provides the following benefits and harms to be assessed before taking a decision:
What result will the mammography give ?
For most women, the result is normal, meaning nothing has been found (negative result). A negative result is reassuring but it does not mean no tumor will ever develop.
Rarely, the tumor can escape observation, (called “false negatives”) - for example in hard-to-interpret cases, namely if the breast is dense, or it might develop between this screening mammography and the next invitation: these are referred to as “interval tumors”. Therefore, talk to your doctor if you notice any changes in your breast between two exams, such as nodules you can feel, skin deformation or hardening, or a bleeding or retracting nipple.
A doubtful result or “positive mammography” means the radiologist has seen images like nodules, masses, calcifications or others that could signal a tumor and thus call for more investigation. This may cause you anxiety and concern but it does not imply a malignant disease. If the suspicion is not confirmed by further tests it is called a “false positive”.
The balance between benefits and harms
In medicine and healthcare a balance must be drawn up between positive effects (benefits) and negative ones (harm) to decide on the utility of an intervention. For mammography screening, the main benefit is the reduction of mortality due to breast cancer in the long-term, while the main harm is the risk of useless treatments.
Once the main results have been established, a balance must be set to gain an idea of their numbers: how many deaths due to breast cancer are avoided by screening programs? How much overdiagnosis is there, namely cases diagnosed in excess?
When the balance is positive, the health authorities can organize a screening program. Leading scientific authorities and societies, following different strategies, sometimes reach different conclusions on the benefits and especially on the harms.
How many fewer women die of breast cancer thanks to screening ?How many excess tumors are diagnosed by the screening ?
The mortality reduction found by researchers is between 20% and 38%.
The difference depends on the methods used to calculate these estimates, and no single one is universally considered better than another Overdiagnosis ranges from 5% to 30%.
The difference depends on the methods used to calculate these estimates, and no single one is universally considered better than another.
How experts have calculated the mortality reduction due to
How experts have calculated overdiagnosis
What happens in the next 30 years ?
source Euroscreen 2012
Out of 1000 women aged 50 who regularly participate in a mammography screening program, in the next 30 years:
71 will receive a diagnosis of breast cancer (discovered by screening or from clinical symptoms)12 will die from breast cancer8 will not die from breast cancer thanks to the screening4 will receive over diagnosis and useless treatmentsIf the same 1000 women are followed without a mammography screening program:
67 will receive a diagnosis of breast cancer20 of them will die due to the breast cancerIn other words, in the next 30 years:
Some women will die from breast cancer anyway: 12 of the 1000 who participate in the mammography screening program compared to 20 if the screening program did not exist. Therefore 8 out of 1000 women are saved from death due to breast cancer; 4 of the 1000 women receive a diagnosis and are then treated uselessly for tumors detected by the screening that would probably never emerge. If there is no mammography screening program, there is no overdiagnosis and only evident tumors are treated.
What is breast cancer and how can it be treated ?
The risk of breast cancer depends on different factors (such as age, family history and life-style) and it is the female tumor that causes the most deaths (see chart 1 - I numeri del cancro in Italia. Rapporto AIOM AIRTUM, 2016). Nowadays, there is every chance of a cure (see chart 2 and chart 3 - I numeri del cancro in Italia. Rapporto AIOM AIRTUM, 2016) through the risk of recurrence remains for many years. The probability of a cure depends on the tumor’s biological features.
A tumor can appear in several forms and is caused by uncontrolled growth of breast cells that become malignant.
The tumor cells can grow (when inside the mammary gland this is defined as an in situ tumor) and migrate to other organs, in the form of metastasis. A metastatic tumor is harder to fight so prompt intervention is always important.
SIf the tumor is diagnosed at an early stage, usually treatment is less aggressive.
For most women with breast cancer only the tumor is removed, surgically, with its surrounding tissue, or the whole breast, depending on the extent of local disease. Other treatments, in addition and in different sequences, include radiotherapy, chemotherapy or hormone therapy, which are useful to reduce the chances of the disease recurring. Further therapies are possible or are being tested, especially with biologic drugs for specific groups of patients.
What is mammography screening ?
Mammography is a radiological breast examination that uses very low X-ray doses.
Mammography can identify lesions or nodes you cannot yet feel. This is why it is used for screening in women who have no symptoms or signs, so as to detect any breast cancers at an early stage.
It is advisable to take part in an organized mammography screening program, because it is reliable, with quality control and a standard care schedule already sets up in case further examinations are required. Outside organized mammography screening programs there is no regular quality control by third parties, so quality, is not guaranteed.
The mammography screening and any subsequent diagnosis and treatment (if necessary) within the organized mammography screening program are free of charge.
At what age is mammography screening recommended ?
In Italy the mammography screening program is carried out every two years for women aged 50-69 because there is impressive evidence of the reduction of mortality.
In some Italian regions (Emilia Romagna, Piedmont and Tuscany), the mammography screening program is extended to women aged from 45 to 49 every year and between 70 and 74 every two years. For these age bands the demonstration of the utility of screening is considered sufficient, though the balance of the related benefits and harms is still debated.
The European Code against Cancer (2015) confirmed the recommendation for women aged 50-69 to do the organized mammography screening and, in certain circumstances, also women aged 45-49 and 70-74.
The risks related to radiation
For the Mammography uses X-rays, namely high-energy radiation (also called ionizing) that may damage cells that absorb it, including the development of tumors. Mammography based on quality criteria employs low doses of X-rays so the risk of tumors developing is practically zero.
The amount of radiation from a mammography is comparable to that absorbed in a few weeks from “background radiation”, meaning from radioactive substances in the ground and buildings and to which everyone is normally exposed.
Mammography is comparable to a chest X-ray and is much less dangerous than an abdominal tomography scan.
Comparison of doses of radiation from different examinations in adults
MethodEffective dose in adults*Time needed to absorb the same dose from background radiation
Computerized Bone Mineralometry0,001 mSv3 hours
Limb X-ray0,001 mSv3 hours
Intraoral X-ray0,005 mSv1 day
Chest X-ray0,1 mSv10 day
Mammography0,4 mSv7 weeks
Spinal X-ray1,5 mSv6 months
Upper abdomen X-ray6 mSv2 years
Chest computed axial tomography (CAT scan)7 mSvmorre than 2 years
Lower abdomen X-ray8 mSvalmost 3 years
Abdomen-pelvi CAT scan10 mSvmore than 3 years
The effective dose used for the comparison is quantified considering the type of radiation and the specific sensitivity of the body part involved; the measurement units are milliSievert (mSv)
What happens at each screening ?Data from the Italian organized mammography screening program
In Italy, out of 1000 women participating in each screening, on average:950 women will receive a “negative” result (no tumor) after the first examination and will be invited to attend the next examination; for 1-2 of them it will prove to be a “false negative”;50 womenof the 1000 will receive a “positive” result (suspicion of tumor) and a further appointment will be set for deeper analysis.Among these 50 women:for 45 the suspicion of a tumor will prove unfounded (false positive) and they will be invited to attend the next screening;for the other 5 women the suspicion will be confirmed and they will be treated in qualified centers.In other words:In the majority of cases the mammography is normal (negative results for 950 out of 1000 women);Many doubtful cases prove normal after further analysis (false positive for 45 out of 50 women);There is the extremely rare possibility that a tumor is not identified (false negative). This may happen to 1-2 women out of 1000 and the tumor is generally discovered because of a nodule or breast lesion.To discover what you can expect 30 years after taking part in a screening program click here
Diagnostic programs in uncertain cases
When the first mammography gives a doubtful result, the woman is invited for a breast examination and a second mammography and/or echography (both not invasive) to confirm or exclude the real presence of a tumor.
The breast examination is done by a skilled physician who will recognize visually and by palpation even small but significant breast changes.
When it is not possible to exclude a tumor even after further examinations, sampling the suspect nodule is generally suggested (biopsy or fine-needle aspiration): this occurs in about 30% of cases. The result of the biopsy is communicated by the physician who first visited the patient, at her next appointment.
The breast comprises a glandular part and an adipose one (fat). When the adipose part is the main one the mammography profile is clear, while the appearance is denser when the glandular component is greater.
When the breast is dense the mammography is harder to interpret and a very small tumor may not be detected giving a “false negative” result.
Usually the density changes over time as the glandular part decreases with age. That explains why in general mammography is clearer in older women.
To reduce the probability of breast cancer
What to doWhat not to do
Keep ideal weight (BMI <24,9 kg/m2) with a diet based on vegetables (unrefined cereals, legumes, starchy vegetables, and fruits) no alcohol or 1 glass of wine a day at the most 1
Marked overweight (BMI>28) in menopause1,2
Follow the Mediterranean diet, with a supplement of extra-virgin olive oil2
Suffer of metabolic syndrome after menopause3,4
Eat fruit and vegetable during adolescence (>3 portions a day)3
Drink more than a single dose of alcohol a day (most risk during adolescence)5,6
Physical activity (150 minutes of moderate intensity a week at least)4,5
Eat large amounts of red meat (>3 a week)7,8,9,10,11
Eat fiber (around 30g a day benefits is greatest especially during adolescence)6,7
Smoke (most risk during adolescence)12
Follow a vegan diet though it is considered an incomplete diet8Use HRT (hormone replacement therapy) in menopause13,14,15
The main risk and protective factors
The risk of breast cancer depends on several factors that can be divided into two groups: those that are unchangeable and those that can be reduced by adopting a correct life-style.
Age: the risk rises with age and more than 75% of breast cancers are in women over 50.
Family history: some families report several cases of breast cancer among first-degree (mother-daughter-sisters) or second degree relations.
Genes: BRCA1 and BRCA2 genetic mutations are responsible for almost half of hereditary breast cancers (5-7% of the total).
Age, family history and genetic patterns are factors to be considered in assessing one's own risk, though they cannot be change.
In addition, other factors can influence the risk of breast cancer, raising or lowering it. For example, a high level of estrogen - the main female hormone - facilitates breast cancer. Any other factors that boost their expression, such as hormone replacement therapy (HRT) increase the risks. Pregnancies lower estrogens production, with a protective effect.
In general, a healthy life-style with a diet rich in fruit and vegetables (unrefined cereals, legumes, non-starchy vegetables, and fruit), less alcohol (no or only one glass of wine a day), weight control, especially after the menopause, can all be protective against breast cancer.
Hastert TA, et al. Adherence to WCRF/AICR cancer prevention recommendations and risk of postmenopausal breast cancer. Cancer Epidemiol Biomarkers Prev 2013; 22:1498-508.Toledo E, et al. Mediterranean diet and invasive breast cancer risk among women at high cardiovascular risk in the PREDIMED trial: a randomized clinical trial. JAMA Intern Med 2015; 175: 1752-60.Farvid MS, et al. Fruit and vegetable consumption in adolescence and early adulthood and risk of breast cancer: population based cohort study. BMJ 2016;353: i2343Moore SC, et al. Association of leisure-time physical activity with risk of 26 types of cancer in 1.44 million adults. JAMA Intern Med 2016; 176: 816.IARC Handbooks of Cancer Prevention. Weight control and physical activity. IARC, Lyon, 2002.Bradbury KE, et al. Fruit, vegetable, and fiber intake in relation to cancer risk: findings from the EPIC. Am J Clin Nutr 2014;100(suppl 1):394S.Farvid MS, et al. Dietary fiber intake in young adults and breast cancer risk. Pediatrics 2016; 137: e20151226.Tantamango-Bartley Y, et al. Vegetarian diets and the incidence of cancer in a low-risk populations. Cancer Epidemiol Biomarkers Prev 2013; 22: 286-94.Agency for Healthcare Research and Quality US. Breastfeeding and maternal and infant health outcomes in developed countries. Evidence Report/TA n. 153, 2007.Kwan ML, et al. Breastfeeding, PAM50 tumor subtype, and breast cancer prognosis and survival. J Natl Cancer Inst 2015;107: djv087.
pros and cons of mammography screening
organized mammography screening program
balance between benefits and harms
Bhaskaran K,et al. Body-mass index and risk of 22 specific cancers: a population-based cohort study of 5.24 million UK adults. Lancet 2014; 384:755.IARC Handbooks of Cancer Prevention. Weight control and physical activity. IARC, Lyon, 2002.Esposito K, et al. Metabolic syndrome and risk of cancer: a systematic review and meta- analysis. Diabetes Care 2012; 35: 2402-11.Berrino F, et al. Metabolic syndrome and breast cancer prognosis. Breast Cancer Res Treat 2014; 147: 159.Schutze M, et al. Alcohol attributable burden of incidence of cancer in eight European countries based on results from prospective cohort study. BMJ 2011;342: d1584.Liu Y, et al. Alcohol intake between menarche and first pregnancy: a prospective study of breast cancer risk. J Natl Cancer Inst 2013; 105:1571-8.Lippi G, et al. Meat consumption and cancer risk: a critical review of published meta- analyses. Crit Rev Oncol Hematol 2016; 97:1.Taylor VH, et al. Is red meat intake a risk factor for breast cancer among premenopausal women? Breast Cancer Res Treat 2009; 117:1-8.Namiranian N, et al. Risk factors of breast cancer in the Eastern Mediterranean Region: a systematic review and meta-analysis. Asian Pac J Cancer Prev 2014;15, 9535-41.Alexander DD, et al. A review and meta-analysis of red and processed meat consumption and breast cancer. Nutr Res Rev 2010; 23:349-65.Farvid MS, et al. Dietary protein sources in early adulthood and breast cancer incidence: prospective cohort study. BMJ 2014; 348: g3437Gaudet M, et al. Active smoking and breast cancer risk: original cohort data and meta- analysis. J Natl Cancer Inst 2013; 105:515-25.Manson JE, et al. Menopausal hormone therapy and health outcomes during the intervention and extended poststopping phases of the Women’s Health Initiative randomized trials. JAMA 2013; 310: 1353-68.Reeves GK, et al. Hormonal therapy for menopause and breast-cancer risk by histological type: a cohort study and meta-analysis. Lancet Oncology 2006; 7: 910-8.Jones ME, et al. Menopausal hormone therapy and breast cancer: what is the true size of the increased risk? Br J Cancer 2016; 115:607-15.
Differences between false positives and overdiagnosis
It is important to explain the differences between false positives and overdiagnosis.
A positive result is considered false when further examinations after mammography exclude breast cancer.
Overdiagnosis instead means that there is a tumor, it is malignant but will not show itself in the rest of life. Unfortunately, it is still not possible to distinguish a tumor of this type so all are treated and the woman will never know what her situation really was.
How are the rates of specific mortality reduction and overdiagnosis measured ?
Current medical science bases its knowledge on the results of experimental or observational studies on samples of the subset population. This rigorous method reduces the differences in opinion among physicians but does not eliminate them. The studies cannot give exact figures, but only a range of estimates that are probably close to the real figure (a bit like poll results for elections).
For mammography screening too, experimental and observational studies are analyzed. Experimental ones follow women for some time, dividing them into two groups: those who are take part in the periodical screening program; those who are not invited serve for “comparison”. Each woman is assigned by chance, as if by tossing a coin, to one group or the other. Later, mortality rates and breast cancer frequency in both groups are measured and compared. Experimental studies about mammography screening (8 clinical trials between 1963 and 1991) have evaluated around 500,000 women aged 40-74 in Europe and North America. The observational studies we consider examined screening programs in the 2000s and refer to women included in the screening programs organized according to the European guidelines who received the first invitation for screening, most of them aged 50 and 74 years.
To reach the most reliable conclusion, decisions are based on the results of many studies, called systematic reviews, that analyze together the results of experimental or observational studies, even if they have some different features. A method to decide what type of studies to include (for example only experimental, only observational, or both) is needed in order to weigh their different quality. Screening programs started on the basis of experimental study results, in the early 1990s. The age for starting screening was debated: 40 years in the USA and more than 50 in Europe (usually up to 69). After that, several research groups conducted systematic reviews of all the studies using methods and strategies for quality assessment that have given different results, leading to debate among the researchers themselves.
For further reviews of results about mortality rates click here
For those about overdiagnosis click here
Different estimates of the reduction of mortality due to breast cancer
The main reviews considered are the recent ones by the Cochrane collaboration (systematic review of experimental studies updated to 2013) and the Independent UK Panel (2012) that also evaluated only experimental studies; the Euroscreen Group included only observational studies based on European programs (2012) (see the sources).
The Cochrane review of experimental studies considers all invited women aged 40-74 and followed for 13 years, and estimates around a reduction of 20% of specific mortality for the whole series of studies, and around 0% omitting the less reliable studies.
The Independent UK Panel review, based on the same experimental studies and on all invited women aged 40-74 and followed for 13 years, also found a 20% mortality reduction, considering all the sufficiently reliable studies.
The Euroscreen review of European observational studies estimated a reduction of mortality due to breast cancer around 25% for women aged 50-69 in an organized mammography screening program. In addition, the reduction of mortality due to breast cancer for women regularly participating in a mammography screening program was about 38%.
Both the Cochrane and the UK Panel estimates are based on the same studies but used different methods and definitions. Those used by the Euroscreen group were similar to those used by the UK Panel even though the former examined observational studies, so the three reviews are not directly comparable. The Euroscreen appraisal answers to the question of what a woman would expect on deciding to take part in a European screening program, concerning the reduction of specific mortality. Therefore, the planners of the screening program you are invited to attend consider the Euroscreen estimates as most reliable to inform individual choices.
Different overdiagnosis estimates
The main reviews considered are the recent ones by the Cochrane collaboration (systematic review of experimental studies updated to 2013) and the Independent UK Panel (2012) that also evaluated only experimental studies; the Euroscreen Group included only observational studies based on European programs (2012) (see the sources).
To quantify overdiagnosis
from a general population perspective, the question is: “Out of all the women aged between 50 and 80 years who receive a diagnosis of breast cancer, what is the proportion overdiagnosed by the screening?”. To answer, the Euroscreen review in 2012, that included only observational studies, estimated that out of 1000 women aged 50 starting with a regular screening program, over the next 30 years 71 cancers will be found and 4 of them will be overdiagnosed and treated uselessly. That harm is around 5% in relative terms (measure A);
from an individual perspective, the question is: “Participating in a screening program and receiving a diagnosis of tumor by the screening, what is the probability that it is an overdiagnosis?”. The estimate is around 10% (measure B).
The difference is due in particular to the fact that measure B considers only women diagnosed due to the screening.
In the Independent UK Panel’s review, based on three experimental studies, overdiagnosis reached about 11% when expressed as the proportion of all tumors found among the invited women (measure A), and 19% as the proportion of only tumors diagnosed during the active screening period (measure B).
The Cochrane review, based on several experimental studies (ages 40-74), analyzed the excess of treatments (mastectomies and conservative procedures), indirectly reaching an estimate of overdiagnosis around 30%, including - as the denominator - all tumors diagnosed in the control group at the end of the follow-up.
The Cochrane and UK Panel’s estimates are both based on experimental studies but used different methods and definitions. Those used by the Euroscreen group were similar to those used by the UK Panel but analyzed observational studies, so the three reviews are not directly comparable.
pronta a scegliere
To make a choice you need correct and complete information. Here is a map of all the contents, with the pages you have already visited highlighted.
However, we realise that your choice will not be based only on the information acquired, and other points will influence the decision: your values, your experience, your perception of the risk of developing this disease. These are important aspects that guide many of our choices and this is why we have returned to them in this final section.
Here are the main points that can influence your decision to participate in mammography screening. For each one you will find a cursor that you can move for or against participation or that you can keep in the middle if that particular aspect doesn't matter to you.
The whole picture which you can print and share with people you trust - gives an overview of your position.
mi sono informata quanto basta
I informed myself enough
ready to choose
In favor of participation
3 2 1 0 1 2 3
Breast conservation thanks to early diagnosis motivates you
The fact that experts disagree on the size of the main benefits and harms for you motivates you
The possibility of a false positive result, that meaning the suspicion of a tumor that is not actually there motivates you
The harm of radiation received with mammography motivates you
The anxiety of the examination and having to wait for the result motivates you
The fear of a diagnosis of breast cancer and its consequences motivates you
The risk of unnecessary treatments (overdiagnosis and overtreatment) motivates you
Your perception of the risk of developing a tumor motivates you
The reduction in breast cancer mortality thanks to early diagnosis motivates you
The quality of the organized screening program offered by the public health service motivates you
EUROSCREEN Working Group. J Med Screen 2012;19(Suppl1).Independent UK Panel on breast cancer screening. The benefits and harms of breast cancer screening: an independent review. Lancet 2012;380:1778-86.Gøtzsche PC, Jørgensen KJ. Screening for breast cancer with mammography. Cochrane Database Syst Rev 2013;6:CD001877.