Analysis of clinicopathological features and prognosis in 68 patients with chromophobe renal cell carcinoma

Objective: To investigate the clinicopathological features and prognosis of chromophobe renal cell carcinoma (ChRCC). Methods: The clinical data of 68 ChRCC cases treated in our department between January 2003 and September 2010 were collected and retrospectively analyzed. The prognostic factors were evaluated by Log-rank test. Kaplan-Meier survival curve was used to estimate the survival rate. Results: Fifty cases were treated with radical nephrectomy and 18 with partial nephrectomy. The mean tumor size was 5.7 cm(1.5-16.0 cm). The TNM stages were as follows: pT1aN0M0 in 25, pT1bN0M0 in 22, pT2aN0M0 in 9, pT2bN0M0 in 5, and pT3aN0M0 in 7. According to the Fuhrman grading system, 8 patients were classified as grade I, 42 cases were grade II, 14 cases were grade III, and 4 cases were grade IV. The 3-year and 5-year survival rates were 93.0% and 90.0%, respectively. The log-rank test showed that tumor size (>7 cm vs. ≤7 cm) (P = 0.004), TNM stage (T1-2 vs. T3-4) (P = 0.008) and urinary collecting system invasion (P = 0.024) were associated with survival time. The multivariable Cox regression model revealed that tumor size (>7 cm vs. ≤7 cm) was an independent predictor of aggressive ChRCC (P = 0.038). Conclusions: ChRCC is a distinct type of renal cell carcinoma exhibiting a low degree of malignancy. Most tumors are larger, but predominantly with a favorable prognosis. Fuhrman nuclear grading is not suitable for ChRCC. Tumor size (>7 cm vs. ≤7 cm) is an independent predictor of prognosis of ChRCC.