Is breast cancer being overdiagnosed?

Cancer screening programs—to find cancers at an early stage—have been credited with saving lives from breast, colon, skin, and prostate cancers. Still, over the past few years, many of these programs have become controversial, as doctors are trying to determine: 1) who should be screened; 2) how often screening should be done; and 3) what is the best screening technique (exam, x-ray, blood test, etc.).

Regarding breast cancer, in Brazil, the Instituto Nacional de Câncer (INCA) has published guidelines. For women age 40 to 49, the recommendation is “a yearly clinical exam with mammography for abnormal findings”.

For women in the 50 to 59 year age range, the recommendation is “a breast exam yearly and mammography every two years”. Depending on clinical exam and risk factors, these schedules are modified, and sometimes women below age 40 should also be screened.

It is important to note that a breast screening program needs to be individualized for each woman, and that is something you should discuss with your own doctor.

Here is also something you might wish to discuss with your doctor. Two studies have been published recently suggesting that cancer screening programs might be responsible for a significant rate of “overdiagnosis” of breast cancer.

A study published November 22 in the New England Journal of Medicine (USA) concludes that 31% of cases of breast cancer are overdiagnosed.

Here is an explanation and possible reason for overdiagnosis: with advanced digital mammography, radiologists now can detect tiny lesions that never would have been found with the techniques of twenty years ago, but now they are. And some of these tumors might not even grow to cause symptoms or spread or pose any risk to the patient’s life.

Yes, in some cases, very small cancers may remain limited in size over many years, but a problem is that doctors don’t know—when they find a very small, early breast cancer—which ones will grow and which ones will remain small and not cause problems. So, to be safe, the tendency is to treat every cancer found.

The other research, published April 3, 2012 in Annals of Internal Medicine, studied 39,888 Norwegian women, and concluded that between 18 and 25% of cancers found via cancer screening programs were overdiganosed.

This concept may be startling to people who have grown up with the concept that all cancers need to be treated as soon as they are found, in the earliest possible stage. But what medical science really needs is the ability to tell, at a cancer’s early stage, if that particular cancer will grow and risk the patient’s life, or continue to stay small and not cause problems.

Doctors will someday be able to tell by examining the cancer’s genetic material rather than relying on what the cancer looks like under the microscope (the current technique). The chief medical officer of the American Cancer Society says “I believe what we need is a 21st-century definition of cancer.”

The hope is that if a small cancer shows characteristics that it will not grow, that rather than undergo traumatic surgery and/or radiation therapy with accompanied risks, scaring, and complications, that the “benign” appearing cancers just be watched over time to see if they grow or not.

This is a complex topic, filled with controversy, and again, don’t try to make a decision about screening on your own. Some experts believe this entire concept of breast cancer overdiagnosis is incorrect. Talk to your own doctor. Today our goal was to make you aware of this big new concept, and for more details, click on the links within the post!

Click here to read INCA’s Programa Nacional de Controle do Câncer de Mama.

Esta postagem também está disponível em: Portuguese (Brazil)