Overdiagnoses of breast cancers may be less frequent than previously thought. That is: the percentage of cancers discovered thanks to mammography screening that are indolent – will not grow or grow very slowly or, in any case, will not be the cause of death – would be one in 7, according to a new study funded by the US National Cancer Institute. and just published on Annals of Internal Medicine. Significantly lower, therefore, than the one in 3 (approximately) suggested by several estimates prior to this one.
Screening programs and the risk of overdiagnosis
Screening programs for early detection of breast cancer have proven over many years to be of enormous benefit and to save lives, but – as is well known – they also carry potential risks. The main one is precisely that of overdiagnosis. Since it is not possible to know in advance whether a tumor is overdiagnosed or not, even in these cases women undergo physically demanding tests and treatments and find themselves in an emotionally stressful condition for many years. The overdiagnosis and the consequent overtreatment obviously also represent a waste for health economies. For this reason, efforts have been made for some time to quantify the phenomenon of overdiagnosis in public screening programs, with the aim of always better defining for whom and when the potential harm is not compensated by the benefits.
Breast cancer: how to find out in advance
by Tiziana Moriconi
I study
The new study fits exactly into this context, which is scientifically much debated. The authors – researchers from Duke University and Fred Hutchinson Cancer Research Center – assessed the overdiagnosis rate by analyzing data from a cohort of 35,986 women who underwent a total of 82,677 mammograms and who had 718 diagnoses of cancer, collected through Breast Cancer. Souveillance Consortium. They found that a two-year screening program for women between the ages of 50 and 74 would lead to an overdiagnosis rate of around 15%: roughly one in 7 cases, as we said. And that this relationship would essentially remain the same with an annual mammogram.
Quiz: can you recognize the symptoms of breast cancer?
by Tiziana Moriconi
According to the Massachusetts General Hospital editorial accompanying the research, these findings may help women better assess the risk of overdiagnosis. Given that in the US about 7 cancers are diagnosed for every thousand women who undergo mammography screening, it means that about one of these thousand women will be overdiagnosed with a cancer that in all likelihood would not cause problems over the years. It must be said that epidemiological estimates relating to one country do not automatically apply to others, where screening can be applied differently and where other important factors can change, such as the percentage of women adhering, the extent of age groups, the technologies used. Not to mention the methodologies used to analyze the data and make estimates. Even in light of these considerations, however, the decision to undergo mammograms outside of screening – which is quite common – should always be based on an interview with a specialist who knows how to assess the personal risk profile of the individual patient.
Breast cancer, so artificial intelligence will improve diagnoses
by Tiziana Moriconi
A personalized screening study
Speaking of personal risk, there is an interesting European initiative, the MyPeBS (My Personal Breast Screening) study, funded by the EU’s Horizon 2020+ program. The clinical trial compares women who follow the current standard mammography screening strategy adopted in their countries (which includes an invitation to have a mammogram every 2 or 3 years for between 50 and 69 years, in some cases between 45 ei 74) with a personalized screening strategy, in which the type of examination and the frequency are defined on the basis of the personal risk that each single woman has of developing breast cancer. The project, which will also deal with overdiagnosis, involves the clinical centers of several countries, including Italy, and will enlist approximately 85,000 women between 40 and 70 years of age. The study is in the recruitment phase: the women participating in MyPeBS will be monitored for 4 years and the results are expected by the end of 2026.
Mammography Screening: The online tool that helps women choose
by MARTA MUSSO
