Clinicopathologic characterization and outcomes for patients with renal medullary carcinoma: Results from the National Cancer Database.

Abstract

456 Background: Renal medullary carcinoma (RMC) is a rare, aggressive malignancy for which relatively limited characterization exists to date. We evaluated clinicopathologic features, treatment patterns, and variables associated with outcomes for patients with RMC. Methods: We reviewed the National Cancer Database to identify patients diagnosed with RMC between 1998-2012. Overall survival (OS) was estimated using the Kaplan-Meier method. Clinicopathologic features associated with all-cause mortality (ACM) were assessed using Cox regression analysis. Results: We identified 153 patients with RMC, comprising approximately 0.04% of renal malignancies during this time period. Median age at diagnosis for RMC was 24 years (IQR 20, 31). The majority of RMC patients were black (135; 88%), male (108; 71%), and presented with unilateral, right-sided tumors (101; 66%). Notably, nearly half (72; 48.9%) presented with metastatic disease. A total of 92 (64.3%) patients underwent radical nephrectomy (RN), and 2 (1.3%) were treated with partial nephrectomy. Pathologic stage at nephrectomy was ≤pT2 in 30 patients (32.6%), pT3 in 43 (46.7%), pT4 in 7 (7.6%), and N+ in 50 (55.6%). Of the patients who underwent RN, 60 (65.2%) received multimodal therapy (MMT), including radiation (3; 3.3%), systemic therapy (49; 53.3%), and radiation + systemic therapy (8; 8.7%). Of the 59 patients who did not undergo surgical resection, the majority (46; 77.8%) presented with M1 disease. Median OS was 7.8 months for the entire RMC cohort, with 1- and 3-year OS of 34% and 11%, respectively. Notably, median OS for patients presenting with M1 and M0 disease was 5.2 months versus 11.2 months, respectively (p< 0.01). On multivariable analysis, treatment with RN (HR 0.40; p=0.003) or RN+MMT (HR 0.44; p<0.001) were associated with decreased ACM, whereas the presence of metastatic disease at diagnosis remained associated with an increased risk of ACM (HR 1.74; p=0.02). Conclusions: The prognosis for patients with RMC is dismal, with a median OS under 8 months. Further studies, including the development of novel therapies, are needed to establish the optimal multimodal management approach for these patients.