(S045) Equivalent Survival With Breast-Conserving Therapy and Mastectomy in Young Women Under the Age of 40 With Early-Stage Breast Cancer: A National Registry-Based Stage-by-Stage Comparison

April 30, 2015

Our study suggests that while young age may be a poor prognostic factor for breast cancer, there is no evidence that these patients have better outcomes with mastectomy over BCT, supporting the continued use of BCT.

Jason C. Ye, MD, Weisi Yan, MD, PhD, Paul Christos, DrPH, MS, Dattatreyudu Nori, MD, MBBS, Akkamma Ravi, MD, MBBS; Department of Radiation Oncology, New York Presbyterian Hospital/Weill Cornell Medical College; Department of Radiation Oncology, New York Hospital Queens/Weill Cornell Medical College; Division of Biostatistics & Epidemiology, Department of Public Health, Weill Cornell Medical College

PURPOSE: Studies have shown that young patients with early-stage breast cancer (BC) are increasingly getting mastectomy instead of breast-conserving therapy (BCT) despite the lack of clear survival evidence in this approach. We examined the difference between outcomes in young women (aged < 40 yr) treated with BCT vs mastectomy.

METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was queried for women aged < 40 years and diagnosed with stage I or II invasive BC treated with surgery from 1998–2003. Breast cancer–specific survival (BCSS) and overall survival (OS) were evaluated by Kaplan-Meier survival analysis, and the log-rank test was used to compare survival between treatment categories of interest. Multivariable Cox regression model analysis was performed to estimate the predictors of BCSS.

RESULTS: Of the 7,665 women identified, 3,249 (42%) received BCT, while 2,627 (34%) patients had mastectomy and no radiation. There were also 994 (14%) patients who had lumpectomy but no radiation, and 795 (10%) were treated with mastectomy plus radiation. On multivariate analysis, higher stage, estrogen receptor–negative status, and mastectomy plus radiation were found to have a higher risk of BC mortality. When separated by stage, with a median follow-up of 111 months (based on living patients), the BCT and mastectomy-only groups showed no statistically significant difference in BCSS or OS. There was also no difference in non-BC mortality in any-stage disease between the two treatment groups. The group aged 35–39 years (66% of total) was associated with better 10-year BCSS (88%) and OS (86.1%) compared with patients aged 20–34 years (34% of total), who had 10-year BCSS and OS rates of 84.1% and 82.3%, respectively (P < .001 for both BCSS and OS). When patients of each age group were further subdivided into stages I, IIA, and IIB, there was no statistically significant difference in BCSS or OS between the BCT and mastectomy groups for any stage for those aged 35–39 years or for stages I and IIA in the 20–34-year-old age group. However, in patients aged 20–34 years with stage IIB disease only, the mastectomy-only group (n = 183) had significantly inferior 10-year BCSS (64% vs 79%; P = .004) and OS (61% vs 77%; P = .002) compared with the BCT group (n = 183).

CONCLUSION: Our study suggests that while young age may be a poor prognostic factor for breast cancer, there is no evidence that these patients have better outcomes with mastectomy over BCT, supporting the continued use of BCT.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org