Prognostic value of nuclear grading in patients with intracapsular (pT1‐pT2) renal cell carcinoma

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Abstract
BACKGROUND: The TNM classification system considers tumor size and, in particular tumor, greatest dimension as the only prognostic indicator for intracapsular renal cell carcinoma (RCC). The objective of the current study was to evaluate the role of nuclear grading and its importance as a prognostic indicator in patients with intracapsular (T1‐T2) RCC.METHODS: A retrospective study was performed on 213 patients with RCC limited to the kidney who were free from distant metastases at the time of diagnosis and who underwent radical nephrectomy from January 1990 to November 1999. All patients were staged according to the 1997 TNM classification system. Nuclear grading was determined according to the criteria proposed by Fuhrman et al. The patients' status was evaluated last in November 2000. The mean follow‐up was 52 months (range, 12–130 months). The probability of survival was estimated by using the Kaplan‐Meier method, with the log‐rank test used to estimate differences among levels of the analyzed variables. A multivariate Cox proportional hazards model was performed to estimate the relative importance of the variables in predicting survival.RESULTS: The 5‐year disease specific survival rates for patients with pT1 and pT2 tumors were 93.5% and 61.1%, respectively. The 5‐year disease specific survival rates for patients with Grade 1, Grade 2, and Grade 3–4 tumors were 95.9%, 86.8%, and 60.1%, respectively. A comparison of the survival curves both by stage and grade showed a statistically significant difference. For patients with pT1 lesions, the 5‐year disease specific survival rate was 94.2% for patients with Grade 1–2 disease and 89.8% for patients with Grade 3–4 disease. For patients with pT2 lesions, the 5‐year disease specific survival rate was 72.2% for patients with Grade 1–2 disease and 20% for patients with Grade 3–4 disease.CONCLUSIONS: Within intracapsular tumors that measure > 7.0 cm in greatest dimension, nuclear grade is an important morphologic variable for predicting long‐term survival. Identification of patients with nuclear Grade 3–4 tumors is important prognostically to determine the metastatic potential of pT2 tumors, because this subgroup of patients may benefit from adjuvant immunotherapy. Cancer 2002;94:2590–5. © 2002 American Cancer Society.DOI 10.1002/cncr.10510