Yu TJ, et al. - Because of distinct biologic features, invasive lobular carcinoma (ILC) is not the same disease as invasive ductal carcinoma (IDC), so researchers examined breast cancer-specific survival (BCSS) among women (≤ 50 years of age) diagnosed with stage T1–2, N0–1, M0 primary breast cancer with invasive lobular features that were treated with either breast-conserving therapy (BCT, lumpectomy plus postsurgical radiation) or mastectomy with and without radiation. In this study, an absolute superiority was not displayed by any of the treatment options in young women with early-stage ILC.

Methods

• From the Surveillance, Epidemiology, and End Results (SEER) database, women (≤ 50 years of age) diagnosed with stage T1–2, N0–1, M0 primary breast cancer with invasive lobular features between 1998 and 2011 were identified.
• These women were treated with either BCT or mastectomy with and without radiation.
• Using the Kaplan-Meier method, survival proportions were assessed and using Cox proportional hazards models, hazard ratios were determined.
• The primary endpoint included breast cancer-specific survival (BCSS).

Results

• Researchers identified a total of 3,393 eligible young ILC patients.
• Of these, 1,391 (41%) had lumpectomy followed by radiation.
• Patients who received BCT, mastectomy alone and mastectomy with radiation displayed 10-year BCSS rates of 95.7%, 94.2% and 89.3%, respectively.
• As per multivariate analysis, patients assigned to the mastectomy alone group (HR=0.86; 95%CI 0.57-1.28) or the mastectomy with postsurgical radiation group (HR=0.97 95% CI 0.58-1.62) did not display improved BCSS vs that observed in patients who underwent BCT.
• When separate evaluation of the 1998-2004 and 2005-2011 time periods was performed, no change in results was observed.