Identification of prognostic factors for postoperative recurrence-free survival in T2-stage renal cell carcinoma: a retrospective cohort study

Background: T2-stage renal cell carcinoma (RCC) is associated with high postoperative recurrence risk and heterogeneous outcomes, but stage-specific prognostic factors remain insufficiently explored. This study aimed to systematically analyze the clinicopathological factors influencing postoperative recurrence-free survival (RFS) (defined as the time from surgical resection to the first occurrence of local recurrence, distant metastasis, or death from any cause) in patients with T2-stage RCC and explore reliable independent prognostic indicators for this specific subgroup. Methods: We retrospectively collected clinicopathological data and follow-up records of T2-stage RCC patients who underwent surgery at the Second Hospital of Lanzhou University from January 2018 to December 2023. Postoperative RFS was the primary endpoint. The Kaplan-Meier method was used for survival analysis and survival curve plotting; univariate and multivariate Cox proportional hazards regression models were applied to identify independent prognostic factors. Internal stability of the identified prognostic factors was evaluated using bootstrap resampling (1,000 iterations) and Harrell's concordance index (C-index). Results: A total of 182 patients were included (mean age: 55±13 years; median follow-up: 40 months). After rigorous variable screening (including collinearity elimination and biological independence assessment), five independent prognostic factors for postoperative RFS were identified: the aspartate transaminase to alanine transaminase ratio (AST/ALT ratio) [hazard ratio (HR) =3.295, 95% confidence interval (CI): 1.899-5.719, P