Survival following breast-conserving therapy is equal to that following mastectomy in young women with early-stage invasive lobular carcinoma

Abstract Background Previous observational studies reported the superior survival of patients with early-stage breast cancer who underwent breast-conserving therapy (BCT, lumpectomy plus postsurgical radiation) compared to that of those who underwent mastectomy. Invasive lobular carcinoma (ILC) is not the same disease as invasive ductal carcinoma (IDC) as it has distinct biologic features and thus requires unique consideration and research. Methods We selected women (≤50 years of age) from the Surveillance, Epidemiology, and End Results (SEER) database diagnosed with stage T1–2, N0–1, M0 primary breast cancer with invasive lobular features between 1998 and 2011, that were treated with either BCT or mastectomy with and without radiation. We assessed survival proportions using the Kaplan-Meier method and hazard ratios using Cox proportional hazards models. Breast cancer-specific survival (BCSS) served as the primary endpoint. Results A total of 3393 eligible young ILC patients were identified, 1391 (41%) of which underwent lumpectomy followed by radiation. The 10-year BCSS rates for patients who received BCT, mastectomy alone and mastectomy with radiation were 95.7%, 94.2% and 89.3%, respectively. Multivariate analysis showed that BCSS was not improved in patients assigned to mastectomy alone group (HR = 0.86; 95% CI 0.57–1.28) or mastectomy with postsurgical radiation group (HR = 0.97; 95% CI 0.58–1.62) compared to that in those who underwent BCT. The results did not changed when evaluating the 1998–2004 and 2005–2011 time periods separately. Conclusion None of the treatment demonstrated an absolute superiority in young women with early-stage ILC. Future studies with more detailed analyses of the confounding factors are worthwhile.