Mammograms save lives despite not being infallible

The words “breast cancer” bring up fear, uncertainty, overwhelm or worry in our minds. It is not unfounded, far from it: we are talking about nothing less than the leading cause of death for women in the world.

Due to its importance, since 1990 the Public Health System of the different Spanish Autonomous Communities has been incorporating the population screening program. The objective: that women between 50 and 69 years old can have a mammogram every two years at health centers.

But to what extent does this test save lives? Do we really know its benefits and risks?

There are false positives and overtreatment, but it is still the best method of early diagnosis
To answer, let's imagine that there is a group of 200 women, aged between 50 and 69, who have a screening mammogram every two years. All of them are followed up for a breast cancer diagnosis until they turn 80 years old. The following can be expected to occur:

• 1 of them will survive breast cancer thanks to screening (otherwise they would have died from the disease).
• 4 of them will die of breast cancer despite having been screened, but having received the appropriate treatments and care to alleviate the pain.
• 8 will be diagnosed and survive, although they would have survived without screening.
• 2 will be diagnosed and treated for breast cancer that would not have been a threat to their life, due to its type or slow growth (what is called overtreatment).
• 40 of these women will need additional diagnostic tests to then rule out that the alteration observed on the mammogram was breast cancer (false positive).

With this information, mammography continues to be the best method for early diagnosis today. And for this reason it is advisable to continue participating in this type of routine check-ups. Although the uncertainty of the diagnosis can generate anxiety, its benefits outweigh the risks it generates for women who participate in the breast cancer screening program.

However, because it is difficult to determine which women would benefit from screening and which could suffer unwanted effects, it would be advisable for them to be able to discuss their personal beliefs and fears about screening with a healthcare professional, be informed about the benefits and disadvantages they may experience, and thus be able to make a more informed decision. A situation that contradicts the recent data that only one in every hundred women has adequate knowledge of mammography and its effects.

How to increase the effectiveness of screening programs
One possibility to improve the effectiveness of screening programs is to change the current standard screening based on age criteria to one personalized according to each woman's risk of being diagnosed with breast cancer. This risk is determined according to personal characteristics, family history, genetic characteristics, previous history of breast disease, among others.

In this way, the screening program can be adjusted more precisely, for each woman and in relation to her risk, in the age of entry and exit from the program, the frequency and type of test. Thus, for example, women at higher risk can join the screening program earlier and have the exam more frequently, while those at lower risk can distance themselves. That is, focus resources on those who demand the most attention, and achieve more efficient use.

Although we have made a lot of progress since the implementation of the screening program, we still have challenges ahead, for which we are all relevant: clinicians, public authorities, health managers, academics, women, their families, etc.

International Breast Cancer Day is an opportunity to become aware of the importance of screening, adopt preventive activities and promote the need to inform ourselves in order to make a decision.

Source: The Conversation. Author: María José Hernández Leal, Doctor Assistant at the Faculty of Nursing, University of Navarra

Outstanding image: Shutterstock / Gorodenkoff