Breast self-examination (BSE) has long been considered by many to be an opportunity for women to self-detect breast masses that may develop between screening sessions. The premise is that women who detect interval cancers and present earlier than their scheduled screening are more likely to be diagnosed with an earlier stage breast cancer. Using BSE for screening has long held a strong intuitive appeal for women, and it has been advocated and widely promoted for many years by various medical societies, breast cancer advocacy groups, and the media as an effective screening tool. BSE has been an integral part of breast cancer screening recommendations for many years.
Although BSE was first presented in the 1930s as a tool in the early detection of breast cancer, studies evaluating its effectiveness were not published until the late 1970s. Since then, numerous observational, cohort, case control, and non-randomized community studies provided conflicting results regarding the benefit of BSE on the stage of disease at diagnosis and breast cancer mortality.1
We now have 2 randomized trials that have investigated the risks and benefits of BSE. The first randomized trial of BSE was begun in 1985 in Leningrad (now St. Petersburg) and Moscow.2 After approximately 13 years, the number of breast cancers was similar in the BSE and non-BSE groups, and no difference in mortality was seen (relative risk [RR], 1.07; 95% confidence interval [CI], 0.86-1.34). Additionally, breast cancer was not diagnosed at a smaller size or at a less advanced stage in the women in the BSE arm. The BSE group had a higher number of excisional biopsies for benign lesions. However, these findings were significantly compromised by lack of compliance with the intervention in the BSE group, which precluded any effect on BSE recommendations or practice.
A study in Shanghai by Thomas et al.,3 which was a randomized, controlled trial assessing the benefit of BSE instruction, represents a landmark investigation in breast cancer screening. The findings, published in 2002 after 10 to 11 years of follow-up, showed no reduced mortality from breast cancer in women who received BSE instruction compared with women who did not (RR, 1.04; 95% CI, 0.82-1.33; P = .72).
In this study, 135 (0.10%) breast cancer deaths occurred in the instruction group and 131 (0.10%) in the control group, and survival in the instruction group was 95.2% (95% CI, 95.1-95.3) compared with 94.9% (95% CI, 94.7-95.0) in the control group (P < .001). Furthermore, the cancers were not smaller in size, and no apparent shift in breast cancer stage was detected between the groups. However, the authors note a substantial increase in detection of benign breast lesions (false-positives), resulting in significantly more breast biopsies.
False-positive results can incur considerable costs and risks. In the randomized trials, women performing BSE were much more likely to undergo unnecessary breast biopsies. Additionally, the anxiety associated with the diagnostic evaluation of a breast abnormality can be significant. An additional risk of false-positive findings is the false reassurance it provides to some women for future BSE findings after one or more negative work-ups.
Bevers T. Breast Self-examination. In: Singletary SE, Robb GL, Hortobagyi GN, eds. Advanced Therapy of Breast Disease. 2nd ed. New York: B.C. Decker, Inc; 2004:193-201.
Semiglazov VF, Moiseyenko VM, Manikhas AG et al.. Role of breast self-examination in early detection of breast cancer: Russian/WHO prospective randomized trial in St. Petersburg. Cancer Strategy 1999;1:145-151.
Thomas DB, Gao DL, Ray RM et al.. Randomized trial of breast self-examination in Shanghai: final results. J Natl Cancer Inst 2002;94:1445-1457.
Baxter N. Preventive health care, 2001 update: should women be routinely taught breast self-examination to screen for breast cancer? Can Med Assoc J 2001;164:1837-1845.
U.S. Preventive Services Task Force. Screening for Breast Cancer. Agency for Healthcare Research and Quality, Rockville, MD. February 2002. Available at http://www.ahrq.gov/clinic/3rduspstf/breastcancer/. Accessed October 2009.
Smith RA, Saslow D, Sawyer KA et al.. American cancer societyguidelines for breast cancer screening: update 2003. CA Cancer J Clin 2003:53;141-169.