Significance of macroscopic tumor necrosis as a prognostic indicator for renal cell carcinoma

We investigated the prognostic significance of macroscopic tumor necrosis in renal cell carcinoma.

We retrospectively analyzed the records of 485 patients who underwent surgical treatment for organ confined or metastatic renal cell carcinoma. The presence or absence of tumor necrosis was evaluated based on macroscopic description of the tumor, and tumors were considered necrotic only if they exhibited more than 10% macroscopic necrosis.

Macroscopic tumor necrosis was identified in 27% of total patients. Patients with macroscopic necrotic renal cell carcinoma were more likely to have larger tumor, metastatic disease, higher local stage and higher tumor grade (all p < 0.001). Pathological features of microvascular invasion (p = 0.026) and sarcomatoid differentiation (p = 0.002) along with several laboratory findings were also observed to be associated with macroscopic tumor necrosis. Among the total subjects those without macroscopic tumor necrosis had significantly higher progression-free (p < 0.0001) and disease specific survival (p < 0.0001). When survival analysis was limited to nonmetastatic tumors only, the same logic applied, which was not the case for the patients with metastatic disease (p > 0.05). Among the different histological subtypes of renal cell carcinoma, macroscopic tumor necrosis was observed to have a significant impact only for the clear cell subtype. In patients with nonmetastatic RCC multivariate analysis revealed that macroscopic tumor necrosis (p = 0.004) was an independent prognostic predictor of disease specific survival along with pathological T stage, tumor grade and tumor size.

Our results suggest that macroscopic tumor necrosis may be a reliable prognostic indicator for nonmetastatic clear cell renal cell carcinoma which should routinely be examined for during pathological analysis.