Ductal Carcinoma in Situ in Young Women: Increasing Rates of Mastectomy and Variability in Endocrine Therapy Use

Background Young women with ductal carcinoma in situ (DCIS) represent a unique cohort given considerations for future risk reduction and treatment effects on fertility and quality of life. We evaluated national patterns of care in the treatment of young women and the impact of those treatments on overall survival (OS). Methods Women younger than 50 years of age diagnosed with pure DCIS from 2004 to 2016 in the National Cancer Database (NCDB) were identified. Clinical, demographic, and choice of local therapy are summarized and trended over time. OS was analyzed using Cox proportional hazard models. Results A total of 52,150 women were identified, and the most common surgical treatment was breast-conservation surgery (BCS; 59%). Bilateral mastectomy (BM) increased in frequency from 2004 to 2016 (11-27%; p < 0.001). In women < 40 years of age, BM (39%) surpassed BCS (35%) in 2010 with a continued upward trend. On multivariable analysis, no OS benefit of BM (hazard ratio [HR] 0.99, p = 0.90) or unilateral mastectomy (UM; HR 0.98, p = 0.80) was observed when compared with BCS + radiation therapy (RT). Inferior OS was seen with BCS, Black race, estrogen receptor (ER)-negative, and tumor >= 2.5 cm (p <= 0.006). In ER+ patients, there was a significant difference in endocrine therapy (ET) use between BM (11%), UM (33%), and BCS (28%) compared with BCS + RT (64%, p < 0.001). Conclusion The use of BM for DCIS is increasing in younger patients and now exceeds breast-conservation approaches in women < 40 years of age with no evidence of improved OS. Among ER+ patients, the rates of ET are lower in the BM, UM, and BCS-alone groups compared with BCS + RT.