- Mammography can miss cancers that need treatment, and in some cases find disease that does not need treatment, leading to overtreatment with toxic therapies. Harms for healthy women who do not have cancer can include unnecessary imaging tests and biopsies, unnecessary exposure to x-ray radiation, and psychological trauma and anxiety.
- All breast cancers are not equal. Some patients will have fast-growing, aggressive tumors while others will have slower-growing, less aggressive tumors that are less likely to metastasize and, therefore, have a better prognosis. Screening is more likely to identify the slower-growing, less aggressive tumors because of longer asymptomatic periods. This “length-time” bias can make screening appear more beneficial than it is. “Lead-time” bias can also contribute to a misrepresentation of the benefit of mammography. If a lethal cancer is found earlier through screening, the patient would appear to live longer because of “lead time.” Screening is not helping patients in these situations live longer, it is only helping them find out about their cancers sooner.
- Breast self-examination (BSE) is ineffective and potentially harmful. Two large, randomized, clinical trials of BSE, both found that women who did BSE were no less likely to die of breast cancer than those who did not do BSE. In both studies, the number of invasive cancers diagnosed in the two groups was about the same, but women in the BSE group had more breast biopsies and more benign lesions diagnosed than did women in the control group. The USPSTF recommends against teaching breast self-examination.
- The USPSTF concludes that there is insufficient evidence to evaluate the benefit of clinical breast examinations.
We encourage women to make informed decisions regarding screening based on the actual evidence. To learn more about the myths and truths concerning breast cancer and screening, and to find out how to take action against this disease, visit StopBreastCancer.org.