Widely hailed for saving lives through early detection of breast cancer, mammography may in fact “do more harm than good,” writes Roni Rabin of the New York Times. Rabin reports that British health care advocates and experts complained in a letter to The Times of London that candidates for mammography receive informational fliers that exaggerate the exam’s benefits and neglect to advise patients of potential harms.
Mammography detects cancers indiscriminatingly, picking up aggressive tumors as well as those so slow-growing that they present no health risks for women who have them. As a result, for every woman saved from deadly breast cancer by routine mammography, at least one other woman would have her life unnecessarily disrupted by overtreatment of a slow-growing cancer that’s not life-threatening.
Mammograms also often result in “false positive” reports which scare women who think the test has shown they have a deadly cancer when further testing shows they have no disease. This is particularly a problem when mammograms are used in low-risk groups like women under age 50.
Further, early detection of the deadly form of breast cancer may not necessarily be life-saving, says Dr. Ned Calonge, chairman of the United States Preventive Services Task Force, which writes consensus reports on all sorts of screening tests, because the cancers are too aggressive to treat even when found early.
In addition to unnecessary emotional distress and extraneous treatment and related costs, other potential harms of mammography include exposure to radiation during the exam.
On the other hand, many doctors, including the director of cancer screening for the American Cancer Society, still believe mammography should be recommended to women of normal risks for breast cancer (e.g. over 50 years of age, family history of the cancer), preferring overdiagnosis to delayed diagnosis.
Before a more definite conclusion is reached within the scientific community, patients should educate themselves about the benefits and harms of mammography, because the ultimate decision of whether to be screened is in their own hands.