Increased Screening Has Led to Breast Cancer Overdiagnosis

Overdiagnosis of breast cancer can lead to unnecessarily aggressive treatments and mastectomies.

An increase in screening has led to an overdiagnosis of breast cancer, which can lead to overtreatment for slow growing cancers that would likely not have become life-threatening during a woman’s lifetime, according to research presented at the 2020 virtual San Antonio Breast Cancer Symposium.

Increases in breast cancer screening has led to a decreased in deaths from the disease. With early detection, care providers are able to use less aggressive therapies and offer breast reconstruction to patients. There are also economic benefits due to the avoidance of advanced disease, along with the psychological, social, and quality of life gains.

New research suggests that 40% to 50% of all screen-detected breast cancers in 2020 would represent overdiagnosis. A 2015 study showed that if 1000 women were screened for breast cancer every 2 years for 20 years starting at 50 years of age, 2 breast cancer deaths would be averted. There would also be 200 false positives, 30 unnecessary biopsies, 30 interval cancers, and 15 over-diagnosed cancers.

According to presenter Philippe Autier, MD, PhD, one way of reducing harm associated with screenings would be to do less of them. There is no evidence that 10 screening rounds is less effective than 30 to 40 screening rounds, he said.

Additionally, care providers should avoid peri-operative MRI and MRI screening of the contralateral breast. This increases ipsilateral and bilateral mastectomies without evidence it reduces mortality, according to Autier. Breast density should also determine screening frequency and method.

According to Autier, cancer detection rate should no longer be the main endpoint when testing new screening technologies.

“In fact, we should just ditch this endpoint and change to incidence rates of advanced-stage cancer, interval cancer rates, and rates of extra cancers staged zero or one,” Autier said.

Risk-based screening can help improve the harm-to-benefit-balance of screening. According to the presentation, lessons can be learned from screening in developing countries.

REFERENCE:

Improvements necessary to increase benefits, decrease harms of breast cancer screening [News Release] December 9, 2020; San Antonio, TX. Accessed December 9, 2020. https://www.sabcsmeetingnews.org/improvements-necessary-to-increase-benefits-decrease-harms-of-breast-cancer-screening/.