NASHVILLE – Many more breast cancer patients now opt for mastectomy, including removal of both breasts, instead of choosing breast conservation surgery (BCS), even with early-stage disease confined to one breast, according to a new study.

The rates of increase were steepest among women with lymph node-negative and in situ disease, according to Vanderbilt University researchers, who noted the reversal of trends seen since the 1990s, when BCS was found to produce equivalent cancer outcomes and was endorsed as a standard of excellence by a National Institutes of Health Consensus Conference.

The study, published online recently by JAMA Surgery, was funded by the VA and used facilities of the VA Tennessee Valley Healthcare System in Nashville.1

For the study, researchers used the National Cancer Data Base to study records of more than 1.2 million adult women treated at centers accredited by the American Cancer Society and the American College of Surgeons Commission on Cancer from Jan. 1, 1998, to Dec. 31, 2011.

In that time period, 35.5% of those women underwent mastectomy, with the adjusted odds of mastectomy in BCS-eligible women increasing 34% during the most recent eight years of the study period. Rates of bilateral mastectomy as a result of cancer in one breast increased from 1.9% to 11.2% from 1998 to 2011.

In women undergoing mastectomy, rates of breast reconstruction increased from 11.6% to 36.4% in the same time period.

Mastectomy rate increases in the U.S. were especially common in younger women with noninvasive disease, those with smaller tumors and those with node-negative disease, indicating the cancer was less likely to spread beyond the initial tumor, according to the study.

The authors suggest that several trends might be influencing patient decision-making, including that the National Accreditation Program for Breast Centers expects that all women undergoing mastectomy be offered reconstruction. The Women’s Health and Cancer Rights Act, passed in 1998, mandates insurance coverage of post-mastectomy reconstruction. Earlier research found that the law significantly increased the proportion of women insured by Medicare and Medicaid who underwent reconstructive procedures.

“Our findings of still-increasing rates of mastectomy, breast reconstruction and bilateral mastectomy in women with early-stage breast cancer has implications for physician and patient decision-making, as well as quality measurement,” said lead author Kristy Kummerow, MD.

The study could not determine the number of patients who have tested positive for mutations in the BRCA gene which greatly increases the risk of developing breast cancer, and may influence women to remove both breasts. The research also could not determine the number of patients whose tumors have been identified as triple-negative; those hormone receptor negative tumors are more aggressive and difficult to treat.

1 Kummerow KL, Du L, Penson DF, Shyr Y, Hooks MA. Nationwide Trends in Mastectomy for Early-Stage Breast Cancer. JAMA Surg. 2014 Nov 19. doi: 10.1001/jamasurg.2014.2895. [Epub ahead of print] PubMed PMID: 25408966.