Prognostic Factors, Treatment, and Outcomes in Early Stage, Invasive Papillary Breast Cancer: A SEER Investigation of Less Aggressive Treatment in a Favorable Histology.

Objectives: Invasive papillary breast cancer (IPBCA) represents 0.5% of invasive BCA, and is thought to carry a favorable prognosis. This population-based study reports on prognostic factors, treatment, and outcomes of early-stage IPBCA to explore whether there is any evidence to support less aggressive treatment.

Materials And Methods: IPBCA cases from 1990 to 2009 of the recent Surveillance, Epidemiology, and End Results were analyzed. Inclusion criteria included patients with stage T1-2, N0 IPBCA. Univariate and multivariate analyses were performed using the variables of treatment, stage, race, hormone receptor status, grade (G1-3), and age. Treatment modalities included lumpectomy alone (LA), lumpectomy with radiation treatment (LRT), and mastectomy alone (MA).

Results: Among 10,485 patients, median follow-up was 56 months. Five and 10-year overall survival (OS) were 93.1% and 76.8%, respectively. Patients treated with LRT had superior mean OS 16.8 versus 14.9 years for MA (P=0.0004) and 14.2 years for LA (P=0.0003). Improved OS also correlated with lower histologic grade (P<0.0001), lower T-stage (P<0.0001), and younger age (P<0.0001). Black patients had the worst OS (12.7 y, P<0.0001).

Conclusions: LRT is associated with superior OS for early-stage invasive papillary BCA patients, when compared with LA or MA in this population-based study. The findings support the standard of care breast conservation approach for patients with invasive papillary BCA. Other prognostic factors associated with worse OS include increased age, higher T-stage, higher histologic grade, and black race.