The Impact of Locoregional Therapy in Nonmetastatic Inflammatory Breast Cancer: A Population-Based Study.

Background: Inflammatory breast cancer (IBC) is a rare but most aggressive breast cancer subtype. The impact of locoregional therapy on survival in IBC is controversial.

Methods: Patients with nonmetastatic IBC between 1988 and 2013 were identified in the Surveillance, Epidemiology, and End Results (SEER) registry.

Results: We identified 7,304 female patients with nonmetastatic inflammatory breast cancer (IBC) who underwent primary tumor surgery. Most patients underwent total mastectomy with only 409 (5.6%) undergoing a partial mastectomy. In addition, 4,559 (62.4%) were also treated with radiation therapy. The patients who underwent mastectomy had better survival compared to partial mastectomy (49% versus 43%, p = 0.003). The addition of radiation therapy was also associated with improved 5-year survival (55% versus 40%, p < 0.001). Multivariate analysis showed that black race HR (1.22, 95% CI 1.18-1.35), ER negative status (HR 1.22, 95% CI 1.16-1.28), and higher grade (HR 1.14, 95% CI 1.07-1.20) were associated with poor outcome. Cox proportional hazards model showed that total mastectomy (HR 0.75, 95% CI 0.65-0.85) and radiation (HR 0.64, 95% CI 0.61-0.69) were associated with improved survival.

Conclusions: Optimal locoregional therapy for women with nonmetastatic IBC continues to be mastectomy and radiation therapy. These data reinforce the prevailing treatment algorithm for nonmetastatic IBC.