A pair of studies reported at the 2011 American Society of Clinical Oncology's Breast Cancer Symposium indicate comparable outcomes - in local recurrence and survival rates - for lumpectomy or mastectomy among women with breast cancer age 40 and younger.

Young age at diagnosis is considered a risk factor for breast cancer recurrence, and there has been a trend in recent years among young women to increasingly choose mastectomy rather than lumpectomy - despite a lack of definitive evidence showing improved survival. As a result, these findings may have important implications in treatment decisions.

The first study was a retrospective study of medical records of more than 600 women aged 40 and younger who were diagnosed with up to stage III breast cancer, analyzed according to the type of surgery (lumpectomy versus mastectomy) the women had. It found no statistically significant difference in local cancer recurrence risk.

In this retrospective study, Julliette Buckley, M.D., a fellow in breast surgery at Massachusetts General Hospital in Boston, and colleagues reviewed medical records of 628 women aged 40 and younger who were diagnosed with up to stage III breast cancer between 1996 and 2008. They examined various patient demographic data, such as tumor characteristics, type of surgery, pre- or post-surgery therapy, site and date of recurrence, and length of follow-up (median follow-up was 72 months), and determined rates of local recurrence, distant recurrence and overall survival.

When they analyzed the data according to the type of surgery the women had, they found no statistically significant difference in local cancer recurrence risk. Thirty out of 421 women who underwent breast conserving therapy and 12 of 161 patients who had a mastectomy developed a local recurrence during the study period. This corresponds to local recurrence rates at 5 and 10 years after breast conservation of 4.6 percent and 13.3 percent, and 8.5 percent and 10.8 percent at 5 and 10 years after mastectomy.

"Although the majority of women in our study underwent breast conserving therapy, previous research has suggested that this procedure leaves women at greater risk for local recurrence. However, we found no significant difference in the rates of local recurrence between women treated with breast conserving surgery or mastectomy. These results suggest that advances in chemotherapy, imaging and radiation have reduced local and distant recurrence risks and have made breast conserving therapy a safe option for many young women," said Dr. Buckley.

In the second study, using the National Cancer Institute's SEER (Surveillance, Epidemiology, and End Results) database, investigators led by Usama Mahmood, M.D., 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."