Treatment outcomes of metastatic nonclear cell renal cell carcinoma: A single institution retrospective analysis

INTRODUCTION: Nonclear cell (NCC) metastatic renal cell carcinoma (mRCC) is a biologically heterogeneous entity. We report the outcomes of NCC mRCC treated with first-line vascular endothelial growth factor (VEGF) inhibitors or mammalian target of rapamycin (mTOR) inhibitors at our institute. This is first such report from India. METHODS: This is a retrospective analysis of the 40 consecutive patients of NCC mRCC treated between January 2013 and June 2015 in routine clinical practice at our institute. The primary endpoint analyzed was overall survival (OS) with respect to the type of first-line treatment and tumor histology. RESULTS: The most common histological subtype was papillary in 25 patients (62.5%) followed by sarcomatoid in six (15%), chromophobe in 5 (12.5%), translocation-associated in one patient, and other nonspecified in three patients. First-line treatment was sorafenib in 14 (35%), sunitinib in 9 (22.5%), pazopanib in 8 (20%), everolimus in seven (17.5%), and best-supportive care (BSC) in two (5%) patients. Partial response, stable disease, and progression was observed in six (15%), 13 (32.5%), and nine (22.5%) cases, respectively, as the best response to first-line treatment. The median OS was 11.7 months and median event-free survival was 6.1 months in the whole cohort. The median OS in months for different first-line treatments were as follows: sorafenib (16.2), sunitinib (11.7), pazopanib (not reached, mean-23.9 ± 6.0), everolimus (4.1) and BSC (0.6) and for different histological subtypes were as follows: papillary (9.8), chromophobe (not reached, mean-30.3 ± 8.4), sarcomatoid (4.1), and others (7.9). CONCLUSIONS: Chromophobe histology has a better outcome compared to other histological subtypes, and anti-VEGF tyrosine kinase inhibitors are preferable first-line agents compared to mTOR inhibitors.