[Clinicopathological features and prognostic analysis of papillary renal cell carcinoma]

To investigate the clinicopathological features and prognostic characteristics of papillary renal cell carcinoma (pRCC).

The clinical data of 114 patients with pRCC, including 91 males and 23 females, admitted to the Department of Urology, Peking University Third Hospital from May 2012 to May 2021 were retrospectively analyzed. All the cases were operated patients with clear pathological diagnosis and complete follow-up data. The log-rank test was used to analyze the relationship between the patients' clinicopathological characteristics and survival time, the Kaplan-Meier method to draw survival curves, and the Cox regression model for univariate and multifactorial analysis.

The mean age of the 114 patients was (57.3±12.6) years. The tumors were located in the left kidney in 49 cases and in the right kidney in 65 cases. In the study, 48 radical nephrectomies and 66 partial nephrectomies were performed, 42 cases were type 1 and 72 cases were type 2, and the mean maximum tumor diameter was (5.5±3.6) cm. pT1a stage 52 cases, pT1b stage 22 cases, pT2 stage 4 cases, pT3 stage 33 cases, and pT4 stage 3 cases were staged. According to the World Health Organization / International Society of Urological Pathology (WHO/ISUP), there were 13 cases of gradeⅠ, 44 cases of grade Ⅱ, 51 cases of grade Ⅲ, and 6 cases of grade Ⅳ. And 34 of the 114 patients had vascular cancer embolism, 30 cases had lymph node metastasis, and 3 cases had adrenal metastasis. The median follow-up time after surgery was 22 months, and the 3-year progression-free survival rate was 95.6%. The patients with type 1 and type 2 pRCC showed statistically significant differences in age (P=0.046), body mass index (P=0.008), surgical approach (P=0.001), maximum tumor diameter (P < 0.001), vascular cancer embolism (P < 0.001), lymph node metastasis (P < 0.001), pT stage (P < 0.001), and nuclear grade (P < 0.001). The 3-year progression-free survival rates for type 1 and type 2 pRCC were 100% and 69.4%, respectively, with type 1 having a significantly better prognosis than with type 2 (P=0.003). Univariate analysis of the patients with type 2 pRCC showed that pT stage (P < 0.001), vascular cancer embolism (P < 0.001) and lymph node metastasis (P < 0.001) were strongly associated with their prognosis. Multifactorial analysis showed that vascular cancer embolism was an independent prognostic factor for progression-free survival in type 2 pRCC (P=0.001). Univariate analysis of the pRCC patients undergoing radical nephrectomy showed that pT stage (P=0.006), vascular cancer embolism (P=0.001), and lymph node metastasis (P=0.008) were significant factors affecting their prognosis, and further multifactorial analysis showed that only vascular cancer embolism was an indepen-dent prognostic factor for their progression-free survival (P=0.006).

Type 2 pRCC has more morbidity, more lymph node metastases, more advanced pT stage, and higher pathologic grading than type 1 pRCC. The presence of vascular cancer embolism is an independent prognostic factor in patients with type 2 pRCC and pRCC undergoing radical nephrectomy.