Mammograms frequently detect small breast tumors that might never become life-threatening, causing women to receive treatment they likely don’t need, a new Danish study finds.
About one in every three women between the ages of 50 and 69 who was diagnosed with breast cancer wound up have a tumor that posed no immediate threat to her health, the researchers reported.
At the same time, mammography did not reduce the number of advanced breast cancers found in women in the study.
“This means that breast cancer screening is unlikely to improve breast cancer survival or reduce the use of invasive surgery,” said study author Dr. Karsten Juhl Jorgensen, deputy director of research for the Nordic Cochrane Center at the Rigshospitalet in Copenhagen. “It also means that breast screening leads to unnecessary detection and treatment of many breast cancers.”
Doctors refer to the detection of non-life-threating cancers as “overdiagnosis.” Women overdiagnosed with breast cancer are frightened needlessly and undergo potentially harmful, but ultimately useless, medical treatments like surgery, chemotherapy and radiation therapy, Jorgensen said.
These results call into question the value of regular mammograms, Jorgensen said. Current U.S. guidelines recommend mammograms every other year for women aged 50 or older, although some medical societies recommend annual screening.
“Breast screening has not lived up to its promises,” Jorgensen said. “All women must seriously consider whether participation in breast screening is right for them, after having sought balanced information about what it can and cannot do.”
But Dr. Otis Brawley, chief medical officer for the American Cancer Society, said the current regimen still saves lives, and women should continue to get mammograms while doctors hone genetic tests that will provide more accurate appraisal of each tumor.
For the study, Jorgensen and his colleagues used data from two comprehensive Danish cancer registries to check the effectiveness of breast cancer screening. They reviewed the medical records of all Danish women diagnosed with invasive breast cancer between 1980 and 2010.
The researchers concluded that between almost 15% to nearly 39% of breast cancers were overdiagnosed.
Guidelines are already shifting to recommend breast cancer screening less frequently, Jorgensen noted. “The American Cancer Society now recommends less frequent screening of a narrower age group than just two years ago,” he said. “Independent expert groups in both Switzerland and France recommend that we stop breast screening entirely because the benefit is doubtful whereas the harms are certain and serious.”
Previous studies have been pointing this direction for years. Mammography and the treatment of cancer is big business and change will come slowly, but it will come. Unfortunately, mammography has become a marketing tool for cancer therapy.
The Bottom Line:
Consider thermography and ultrasound of the breast as viable, non-invasive and safe alternatives to mammography.
Source: January 9, 2017 National Institutes of Health