Pseudocapsule status combined with pathological parameters predicts prognosis in renal cell carcinoma

We evaluated whether pseudocapsule status, alone and in combination with pathological parameters, could serve as a prognostic marker in human renal cell carcinoma (RCC).

We retrospectively analyzed 1560 patients with RCC who underwent surgery at a single institution between 2007 and 2012. The patients were randomly assigned to training (n=780) and validation (n=780) cohorts. Pseudocapsule status was classified as grade 0 (intact pseudocapsule without breakthrough), grade 1 (pseudocapsule invasion), and grade 2 (pseudocapsule breakthrough or absence). A pseudocapsule-pathological parameter score (PPS) was constructed by integrating pseudocapsule status with pathological type, Fuhrman grade, nuclear necrosis, sarcomatoid transformation, microvascular infiltration, Eastern Cooperative Oncology Group performance status score, and tumor-node-metastasis stage. The scores were categorized as low, intermediate, and high. Overall survival and relapse-free survival were evaluated using Kaplan-Meier and Cox regression analyses.

Among the 1560 patients, 529 had grade 0 pseudocapsules, 701 had grade 1 pseudocapsules, and 330 had grade 2 pseudocapsules. The Kaplan-Meier curves revealed better overall survival in patients with grade 0 pseudocapsules than those with grades 1 and 2. Multivariate analyses identified grade 2 pseudocapsule status as an independent predictor of worse overall survival (hazard ratio 3.94, 95% confidence interval 2.09-7.43, p < 0.001) and relapse-free survival (hazard ratio 2.87, 95% confidence interval 1.72-4.81, p < 0.001) in the training cohort. The validation cohort showed similar findings (overall survival: hazard ratio 2.64, 95% confidence interval 1.55-4.49, p < 0.001; relapse-free survival: hazard ratio 2.92, 95% confidence interval 1.81-4.71, p < 0.001). In addition, the PPS was independently associated with overall survival. Compared with the low PPS group, the high PPS group showed significantly worse prognosis in both cohorts (training: hazard ratio 33.58, 95% confidence interval 15.52-72.67, p < 0.001; validation: hazard ratio 18.10, 95% confidence interval 9.35-35.03, p < 0.001).

Pseudocapsule status demonstrated good prognostic implications in RCC. Furthermore, the new PPS system, which combines pseudocapsule status with established pathological parameters, may better predict patient prognosis.