Papillary Renal Cell Carcinoma: Current Evidence and Future Directions.

Papillary renal cell carcinoma (pRCC) comprises 15-20% of all patients with renal cell carcinoma (RCC). Although in the localized setting where pRCC appears to have better outcomes than clear cell RCC (ccRCC), patients with metastatic pRCC have significantly worse outcomes than patients with metastatic ccRCC. Because of the overall rarity of pRCC, there have been less research and clinical trials devoted to this subtype. Therefore, treatment of pRCC has generally been extrapolated from approved therapies for ccRCC. Recent data shows promise with newer tyrosine kinase inhibitors, and there is emerging evidence on their combination with immune checkpoint inhibitors. However, more dedicated clinical trials to pRCC are urgently needed, as response rates and outcomes still lag behind ccRCC. This review summarizes the pathophysiology, genetic features, the evolution of treatment approaches since the systemic cytokine era, and current challenges of managing pRCC.