Clinicopathological features and prognostic factors of clear cell papillary renal cell tumor: a retrospective population-based analysis.

Background: Clear cell papillary renal cell tumor (ccpRCT) is a novel tumor entity which shares morphologic features with clear cell renal cell carcinoma (ccRCC) and papillary RCC (pRCC). The aim of this study was to comprehensively explore the clinicopathological features and prognostic factors of ccpRCT in the real-world setting with the largest cohort to date. Methods: A total of 59,076 eligible RCC patients diagnosed between 2016 and 2021 in the Surveillance, Epidemiology, and End Results database were included in this retrospective analysis. The demographic and clinicopathological variables of ccpRCT patients were compared to those of ccRCC or pRCC patients. The survival curves were generated via the Kaplan-Meier method. The Cox proportional hazards model was used to compare the differences in overall survival (OS) and disease-specific survival (DSS). Results: Compared with ccRCC and pRCC patients, those with ccpRCT were more frequently diagnosed with lower grade (G1/2) and lower stage (I/II), and exhibited prolonged OS and DSS. Univariate Cox regression analysis revealed that age at diagnosis; histological grade; tumor (T), node (N), metastasis (M) and overall stage; treatment type; and history of cancer were significantly associated with both OS and DSS. In addition, age at diagnosis and treatment type were crucial prognostic factors in terms of both OS and DSS according to multivariate Cox regression analysis. Conclusions: Our study demonstrated the highly favorable outcomes in ccpRCT patients with low potential of lymph node invasion, metastasis, or disease specific death, and surgery is associated with improved outcomes.