MASTECTOMY OFFERS NO SURVIVAL ADVANTAGE IN YOUNG WOMEN

Lumpectomy with adjuvant radiation and mastectomy provide "equivalent" overall and disease-specific survival in young women with early breast cancer, according to a new study presented at a press conference today in advance of the start of the 2011 Breast Cancer Symposium.
Young women "should not choose a mastectomy based on the assumption of improved survival," said lead investigator Usama Mahmood, MD, who was at the University of Maryland in Baltimore when the study was undertaken.
"Young age alone does not mandate mastectomy," commented Andrew Seidman, MD, from Memorial Sloan-Kettering Cancer Center in New York City, who moderated the press briefing. His comments related to this study and another reported at the briefing, which found similar rates of local recurrence with the 2 competing surgical approaches.
Using the Surveillance, Epidemiology, and End Results (SEER) database, Dr. Mahmood and colleagues reviewed outcomes among 14,760 women aged 20 to 39 years who were diagnosed with early-stage breast cancer (T1-2, N0-1, M0) between 1990 and 2007.
The women underwent breast-conserving therapy (45%; lumpectomy and radiation treatment) or mastectomy (55%). Everyone in the breast conservation group received adjuvant radiation, but only 17% of the mastectomy group received radiation.
A multivariable analysis that included tumor characteristics found that breast-conserving therapy resulted in similar overall survival (hazard ratio [HR], 0.93; P = .16) and breast cancer–specific survival (HR, 0.93; P = .26) as mastectomy, said Dr. Mahmood, who is now a fellow in radiation oncology at the University of Texas M.D. Anderson Cancer Center in Houston.
Median follow-up duration was 5.7 years.
A matched-pair analysis involving a subset of 4644 of the patients confirmed no difference in overall survival and disease-specific survival, he also said. The patients were matched according to specific factors such as tumor size, tumor grade, and number of positive nodes.
In this analysis, at 5, 10, and 15 years, the overall survival rates for the breast conservation group were 92.5%, 83.5%, and 77%, respectively. For patients who underwent mastectomy, overall survival rates were 91.9%, 83.6%, and 79.1%, respectively. Breast cancer–specific survival rates were also similar between the 2 groups of women, said Dr. Mahmood.
The study's importance is, in part, due to other research findings, suggested Dr. Mahmood. A series of studies presented in the 1980s comparing breast-conserving therapy and mastectomy found equivalent survival among women with early breast cancer. But the number of young women in those studies was small, he said.
Other research has not encouraged the use of breast-conserving therapy in young women, he suggested.
"Previous studies have shown that young women with breast cancer treated with breast-conservation therapy experience higher local recurrence rates," he said. However, those findings were challenged by another study presented at the press conference. The combination of 2 new studies "should make us question that mastectomy is the only option for young women with breast cancer," said Dr. Seidman, who added the caveat that BRCA status is also a key to decision-making in young women.
The new study "serves as a reminder that women should be counseled appropriately about their treatment options," said Dr. Mahmood.
"The data is the data"
The factors included in the multivariate analysis included year of diagnosis, age, race/ethnicity, tumor grade, progesterone receptor status, tumor size, and lymph node status, noted the study authors. Patients had no more than 3 positive nodes, added Dr. Mahmood.
These are standard factors to consider when assessing breast cancer, suggested Dr. Seidman.
The new analysis did not include a number of factors that might also be used to make treatment decisions in the clinic, he further suggested. For instance, there are biological and luminal subtypes, as well the oncotype recurrence score, all of which may help clinicians and patients in their decision-making, he said.
"But most of us don't think about using that information as a decisive factor in the decision to undergo mastectomy or breast conservation therapy," Dr. Seidman said about these more recently identified breast cancer characteristics and newer tests.
Magnetic resonance imaging (MRI) may or may not have an important role to play in this decision-making process, he suggested. It is used to evaluate breast cancer in the preoperative setting to "better select" patients for the type of surgery, he said.
However, whether or not the use of MRI confers a survival advantage is "not settled," according to Dr. Seidman. "There is an epidemic of breast MRI," he said, quoting his colleague Monica Morrow, MD, from Memorial-Sloan Kettering Cancer Center.
"The data is the data," he said about the study, suggesting that any equivocations about the results and any missing factors in the analysis were not merited.
The investigators have disclosed no relevant financial relationships.