Objective:To investigate the clinicopathological characteristics and prognosis of pT 3a stage non-clear cell renal cell carcinoma (nccRCC). Methods:The clinical data of 438 patients with pT 3a stage renal cell carcinoma treated by surgery at Peking University Third Hospital from March 2013 to March 2023 were retrospectively analyzed. Among them, there were 58 cases in the nccRCC group and 380 cases in the clear cell RCC (ccRCC) group. There were statistically significant differences in age, American Society of Anesthesiologists (ASA) classification, and comorbidities between the two groups (all P<0.05). Therefore, propensity score matching was used to adjust the baseline data of the two groups. After matching, there were 58 cases in the nccRCC group and 232 cases in the ccRCC group. There were no statistically significant differences in gender (male/female: 34/24 cases and 165/67 cases), age (53.3±16.8 years and 56.6±11.6 years), ASA classification (1/2/3/4: 19/34/5/0 cases and 60/163/8/1 cases), comorbidities (present/absent: 16/42 cases and 76/156 cases), tumor maximum diameter [6.7 (5.3, 8.4) cm and 5.8 (4.6, 7.8) cm], and nephron sparing surgery(yes/no: 4/54 cases and 15/217 cases) (all P > 0.05). The overall survival (OS) and progression-free survival (PFS) of two groups were compared, the Kaplan-Meier method was employed to plot survival curves. Cox proportional hazards regression model was used to analyze the relationship between different pT 3a characteristics in the nccRCC group and progression-free survival. Results:In the matched cohort, the median follow-up time for the nccRCC group and ccRCC group were 28.0 (16.3, 45.3) months and 31.0 (18.0, 57.0) months, respectively. The pathological types in the nccRCC group included chromophobe renal cell carcinoma (20 cases, 34.5%), papillary renal cell carcinoma (20 cases, 34.5%), Xp11.2 translocation renal cell carcinoma (8 cases, 13.8%), mucinous tubular and spindle cell carcinoma (3 cases, 5.2%), and other or unclassified renal cell carcinoma (7 cases, 12.1%). There was no statistical significance between the nccRCC and ccRCC groups in terms of invasion of the renal vein without involvement of the vein wall (yes/no: 5/53 cases and 41/191 cases), vascular invasion (yes/no: 18/40 cases and 52/180 cases), invasion of the perirenal fat (yes/no: 15/43 cases and 39/193 cases), invasion of the renal pelvis and sinus (yes/no: 51/7 cases and 200/32 cases), or sarcomatoid differentiation (yes/no: 2/56 cases and 4/228 cases)(all P > 0.05). However, there was a statistically significant difference in lymph node involvement (yes/no: 3/229 cases and 9/49 cases, P < 0.01). The 5-year PFS and OS of nccRCC group were 67% (95% CI 52%-86%) and 70% (95% CI 55%-89%) respectively. While the 5-year PFS and OS of ccRCC group were 78% (95% CI 70%-86%) and 87% (95% CI 81%-93%) respectively. There was no statistically significant difference in PFS between the two groups ( P>0.05), but there was a statistically significant difference in OS ( P<0.01). Furthermore, within specific pathological types, the 5-year PFS and OS rates of chromophobe renal cell carcinoma were 88% (95% CI 67%-100%) and 86% (95% CI 63%-100%) respectively, followed by papillary renal cell carcinoma with 5-year PFS of 55% (95% CI 33%-91%) and 5-year OS of 65% (95% CI 44%-97%), and Xp11.2 translocation renal cell carcinoma with 5-year PFS of 38% (95% CI 9%-100%) and 5-year OS of 43% (95% CI 10%-100%). The difference in PFS and OS between ccRCC, chromophobe renal cell carcinoma, papillary renal cell carcinoma, and Xp11.2 translocation renal cell carcinoma was statistically significant ( P<0.01). In addition, the multivariate Cox regression analysis revealed that the independent risk factor for PFS in nccRCC patients is the invasion of the renal vein without venous wall involvement ( HR = 8.0, 95% CI 1.8-36.2, P<0.01). Conculsions:Compared to ccRCC, pT 3a nccRCC is more prone to lymph node metastasis. Among them, papillary renal cell carcinoma and Xp11.2 translocation renal cell carcinoma have a poorer prognosis, resulting in an overall lower survival period for pT 3a nccRCC patients. Among different pT 3a characteristics, invasion of the renal vein without invading the vein wall is an independent risk factor for PFS in nccRCC patients.