(P110) Breast Cancer Before Age 40: Current Patterns in Clinical Presentation and Local Management

Thomas M. Churilla, MD, Christopher A. Peters, MD; Abington Memorial Hospital; The Commonwealth Medical College; Northeast Radiation Oncology Center

Background: Although uncommon in women less than 40 years old, breast cancer in younger women may have unique biologic and treatment implications. The purpose of this study was to evaluate treatment of breast cancer in young women with respect to previously established clinical predictors of local therapy choice.

Methods: The design of the study was a case-control analysis. Using the National Cancer Institute (NCI)-Surveillance, Epidemiology, and End Results (SEER) database, breast cancer cases from 2010 were queried and limited to women between the ages of 20–39 years (cases) and 60–64 years (controls), lobular/ductal histology, nonmetastatic disease, and treatment with surgery. Controls were established based on the median age of women diagnosed with breast cancer. First, we tested for associations between young age (ages 20–39 y) and tumor/demographic variables by calculating the odds ratio (OR) and computing Pearson’s chi-square value. Second, we tested for associations between young age and surgical procedure (breast-conserving surgery [BCS], simple mastectomy, modified radical mastectomy, and bilateral mastectomy). Third, in mastectomy patients, we tested for associations between young age and postmastectomy radiation therapy (PMRT). Finally, we constructed separate multiple logistic regression models for treatment choice (ie, surgery type and PMRT), adjusting for significant (P < .05) univariate relationships with young age (first analysis).

Results: A total of 7,115 patients were analyzed, with 1,518 (21.3%) representing women between the ages of 20–39. Compared with older women (ages 60–64), young women (ages 20–39) with breast cancer were more likely to have large, node-positive, estrogen receptor (ER)-negative tumors with ductal histology and be of minority race in multivariate analysis. Further, 63.2% of older women underwent BCS, whereas only 40.5 % of younger women underwent BCS. The OR of simple mastectomy was 1.30 (95% confidence interval [CI], 1.08–1.56), 2.07 for modified radical mastectomy (95% CI, 1.77–2.41), and 6.42 for bilateral prophylactic mastectomy (95% CI, 5.43–7.58) and significantly associated with young age relative to BCS. However, in multivariate analysis, only bilateral prophylactic mastectomy was significantly associated with young age (OR = 5.10; 95% CI, 4.24–6.13; P < .001). Finally, postmastectomy RT was more prevalent in young women (40.7%) compared with older women (23.1%), which retained significance in multivariate analysis (OR = 1.74; 95% CI, 1.42–2.14; P < .001).

Conclusions: In 2010, younger women with breast cancer were more likely to present with locally advanced, biologically aggressive malignancies. BCS was less common among young women, but this trend appears to be closely related to the tumor characteristics associated with young age and the prevalence of bilateral prophylactic mastectomy among young women. Postmastectomy RT was more frequently administered in young patients after adjustment for tumor and demographic variables.