Using the National Cancer Institute's SEER (Surveillance, Epidemiology, and End Results) database, investigators led by Usama Mahmood, MD, a fellow in radiation oncology at the University of Texas M.D. Anderson Cancer Center, compared overall survival and breast cancer-specific survival among 14,760 women ages 20 to 39 who were diagnosed with early stage breast cancer between 1990 and 2007.

Of these women, 45 percent received breast conservation therapy and 55 percent underwent mastectomy. All patients in the breast conservation group received adjuvant radiation, while 17 percent of the mastectomy group received such radiation.

Median follow-up was 5.7 years.After accounting for a number of patient variables, including year of diagnosis, age, race/ethnicity, tumor grade, progesterone receptor status, tumor size, and lymph node status, they found no difference in overall and cancer-specific survival between the two groups.

The researchers also looked at a smaller subset of 4,644 women who had either breast conservation surgery or mastectomy who were matched according to specific factors such as tumor size, tumor grade, and number of positive nodes.

They again found no differences in overall or cancer-specific survival. After 5, 10 and 15 years, the overall survival for the breast conservation group was 92.5 percent, 83.5 percent and 77 percent, respectively. For those who underwent mastectomy, overall survival was 91.9 percent, 83.6 percent and 79.1 percent, respectively. Breast cancer-specific survival rates were also similar between the two groups of women.

"Our findings provide reassurance that breast conservation therapy leads to similar survival outcomes as mastectomy even in younger women with early stage breast cancer," said Dr. Mahmood, who conducted much of the research while at the University of Maryland Marlene and Stewart Greenebaum Cancer Center. "These findings can provide reassurance to younger women with early-stage breast cancer who are considering less aggressive surgery."

Source: ASCO