Breast-Conserving Therapy Outcomes Deemed Similar to Mastectomy

Two studies released Tuesday demonstrate that women age 40 and younger with breast cancer experience similar outcomes in local recurrence and survival rates whether they undergo breast conservation therapy (BCT) or a mastectomy.

The findings come amid a growing trend among younger women to choose mastectomy over less aggressive surgery, and should encourage patients and clinicians to explore factors beyond age when evaluating treatment options, researchers said during an American Association of Clinical Oncology (ASCO) presscast.

The studies will be presented during ASCO’s 2011 Breast Cancer Symposium, which will be held September 8-10 in San Francisco, California.

A younger age at diagnosis has been established as a risk factor for recurrence, and previous studies have concluded that these patients experience higher rates of local recurrence after BCT (lumpectomy), said Julliette M. Buckley, MB, MD, who headed a research team at Massachusetts General Hospital, Boston.

Buckley and colleagues, however, found no significant difference in the rates of locoregional recurrence (LRR) after analyzing outcomes for 628 women ≤40 who were diagnosed with breast cancer from 1996 to 2008.

At median follow-up of 72 months, the rate of LRR among patients who underwent BCT (30/421) was 7.34%, compared with 7.40% for patients who underwent mastectomy (12/161). Overall, LRR rates were 5.56% at 5 years and 12.11% at 10 years.

The overall survival (OS) rate was 93% at 5 years and 87% at 10 years.

In the second study, researchers compared OS rates among 14,760 women ages 20 to 39 in the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) database who were diagnosed with early-stage breast cancer from 1990 to 2007.

Forty-five percent of the patients received BCT, while 55% underwent mastectomy. All patients in the BCT group were treated with adjuvant radiation while 17% of the mastectomy patients received similar radiation.

Usama Mahmood, MD, a fellow in radiation oncology at the University of Texas MD Anderson Cancer Center in Houston, and colleagues found no difference in OS between the 2 groups.

The OS rates for the BCT group were 92.5%, 83.5%, and 77% after 5, 10, and 15 years, respectively, while the OS rates for the mastectomy patients were 91.9%, 83.6%, and 79.1% after 5, 10, and 15 years, respectively.

Buckley and Mahmood said younger women facing treatment decisions could find reassurance in the data if they choose to have less aggressive surgery.

“Young age alone does not mandate mastectomy,” noted Andrew D. Seidman, MD, an ASCO committee member who moderated the presscast. Seidman, a medical oncologist at Memorial Sloan-Kettering Cancer Center in New York City, said other factors such as BRCA gene mutation status, family history, magnetic resonance imaging testing, and emotional reactions should be considered before patients decide which therapy to choose.

All symposium abstracts are posted at http://breastcasymposium.org.

Buckley JM, Coopey S, Samphao S, et al. Recurrence rates and long-term survival in women diagnosed with breast cancer at age 40 and younger. In: Proceedings from the 2011 Breast Cancer Symposium of the American Society of Clinical Oncology; September 8-10, 2011; San Francisco, CA. Abstract 70.

Mahmood U, Morris CG, Neuner GA, et al. Equivalent survival with breast-conservation therapy or mastectomy in the management of young women with early-stage breast cancer. In: Proceedings from the 2011 Breast Cancer Symposium of the American Society of Clinical Oncology; September 8-10, 2011; San Francisco, CA. Abstract 85.