Histologic coagulative tumor necrosis as a prognostic indicator of renal cell carcinoma aggressiveness

BACKGROUND: Prognostic markers for renal cell carcinoma (RCC), such as patient symptoms, tumor stage, tumor size, and tumor grade, are useful for determining appropriate follow-up and selecting patients for adjuvant therapy. Histologic coagulative tumor necrosis, also reported to be a prognostic marker for RCC, has not previously been extensively described or investigated. Hence, the objective of the current study was to characterize tumor necrosis as a prognostic feature of RCC. METHODS: The authors of the current study identified 3009 patients treated surgically for RCC between 1970 and 2002 from the Mayo Clinic Nephrectomy Registry (Rochester, MN). Associations of tumor necrosis with clinical, laboratory, and pathologic features were examined with chi-square, Fisher exact test, and Wilcoxon rank-sum tests. Cancer-specific survival was estimated with the Kaplan-Meier method, and associations with outcome were assessed with Cox proportional hazard models. RESULTS: Tumor necrosis was present in 690 of 2445 (28%) clear cell, 196 of 421 (47%) papillary, and 28 of 143 (20%) chromophobe RCCs. The risk ratio for death from RCC in patients with necrotic compared with non-necrotic tumors was 5.27 (95% confidence interval [CI]: 4.56-6.09; P < 0.001) for clear cell, 4.20 (CI: 1.65-10.68; P < 0.001) for chromophobe, and 1.49 (CI: 0.81-2.74; P = 0.199) for papillary RCC. The survival difference for clear cell RCC persisted even after multivariate adjustment for tumor stage, size, and grade (risk ratio 1.90; P < 0.001). CONCLUSIONS: Histologic coagulative tumor necrosis is an independent predictor of outcome for clear cell and chromophobe RCC, and it should be routinely reported and used in clinical assessment.