"Many surgeons had noticed that more women were requesting double mastectomy for treatment of the cancer in only one breast. So, we weren't surprised by the overall trend, but we were very surprised by the magnitude," lead author Dr. Todd M. Tuttle said in an interview with Reuters Health.
What is driving this trend will require further studies, added Tuttle, from the University of Minnesota in Minneapolis. In the meantime, he advised, it is critical that physicians be aware and inform their patients that "although there may be sound reasons for undergoing double mastectomy (avoidance of future mammograms and preventing a new cancer), the procedure does not improve breast cancer survival."
The new study involved an analysis of data for 152,755 women who were diagnosed with cancer in one breast between 1998 and 2003 and entered in the Surveillance, Epidemiology, and End Results (SEER), the US National Cancer Institutes' database.
Overall, 4,969 patients elected to undergo preventative mastectomy in the other breast. The rates of the operation were 3.3 percent among women who had any surgery, including those who underwent single mastectomy or only had their tumor removed, and 7.7 percent among mastectomy patients.
The overall rate of double mastectomy - that included removal of an unaffected breast climbed from 1.8 percent in 1998 to 4.5 percent in 2003, the report indicates. Among mastectomy patients, the rate rose from 4.2 percent to 11.0 percent. These trends were noted for patients at any cancer stage and were still apparent at the end of the study period.
Characteristics of the women who underwent double mastectomy included younger patient age, non-Hispanic white race, lobular breast cancer type, and a prior cancer diagnosis, the researchers found. Large tumor size was associated with an increase in the overall rate of the procedure, but with a decrease in the rate among mastectomy patients.
"The main unanswered question from this research is: why are more women choosing to undergo double mastectomy?" Tuttle said. "For our next research project, we will interview breast cancer patients before and after surgery to determine what factors influenced their surgical decisions. We will also interview patients' surgeons to determine their advice."
AUTHOR: Anthony J. Brown, MD
SOURCE: Journal of Clinical Oncology, October 22, 2007 online.