Predictors of pathological upstaging to pT3a after nephrectomy for cT1 renal tumors: a systematic review and meta-analysis

Background: The potential predictors and clinical implications of postoperative pathological upstaging in patients with clinical stage T1 (cT1) renal cell carcinoma (RCC) remain insufficiently characterized. Methods: This systematic review was performed in accordance with the PRISMA guidelines. Databases including PubMed, Web of Science and Embase databases were searched. A total of 17 studies (involving 24957 patients) were included, and relevant factors were analyzed from the perspectives of patients' baseline characteristics, pathology, and imaging findings. Result: A total of 17 studies involving 24,957 patients were included. The overall incidence of pathological upstaging was 7.46%. Through combined qualitative and quantitative analysis, we identified the following independent risk associated factors for pathological upstaging to pT3a: male gender (OR: 1.067; 95% CI: 1.029-1.107;p=0.001), age (OR = 1.029; 95% CI: 1.02-1.038;p = 0.0001), BMI (OR:1.016;95% CI: 1.004-1.027;p=0.0001),cT1b (OR: 5.865; 95% CI: 3.711- 9.267; p = 0.0001),presence of clinical symptoms(OR:1.987; 95% CI: 1.439- 2.744; p = 0.0001), RENAL score= 7-9 (OR = 2.480; 95% CI: 1.516-4.058;p = 0.0001),necrosis on imaging(OR = 2.347;95% CI: 1.570-3.509;p = 0.0001), irregular margins (OR = 2.874; 95% CI: 1.760-4.693;p = 0.0001)and Hilus involvement (OR = 2.134;95%CI: 1.367-3.333;p = 0.001).Furthermore, the unadjusted meta-analysis results indicated an increased risk of recurrence in patients who upstaged to pT3a (HR = 3.50,95% CI = 2.00-6.13). After multivariable adjustment, the association remained consistent and in the same direction (HR = 2.60,95% CI = 1.86-3.64). Conclusion: Current evidence suggests that 9 variables, including advanced age, gender, and irregular margins may be predictors of postoperative pathological upstaging of cT1 RCC. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD420250640397.