Objectives: To analyze pathobiology and prognosis of chromophobe renal cell carcinoma (CRCC).
Patients and methods: We studied 124 patients with CRCC who underwent nephrectomy from 1989 to 2006 at two institutions. Clinicopathological characteristics and survival were compared with 1,693 consecutive patients with clear-cell RCC.
Results: Compared with clear cell RCC, patients with CRCC presented with less advanced tumors, but had a higher prevalence of concomitant sarcomatoid features (15% vs. 6%, P < 0.001). Metastatic CRCC showed a high incidence of sarcomatoid features (50%) and a predilection for liver metastases. The 5-year DSS rate for all patients with CRCC was 78% compared with 60% for patients with clear-cell RCC (P = 0.008). When adjusted for metastatic status, this survival difference disappeared. Nonmetastatic RCCs had similar prognosis (P = 0.157), whereas survival of metastatic CRCC was inferior to that of patients with metastatic clear-cell tumors (median: 6 vs. 19 months, P = 0.0095). In multivariate analysis, ECOG PS, symptomatic presentation, T stage, N stage, M stage, nuclear grade, and presence of sarcomatoid features, but not histological sub-type, were independent prognostic factors of DSS. Ten patients received immunotherapy, none of whom were responders.
Conclusions: Compared with clear-cell RCC, patients with CRCC present with less advanced tumors, which lead to better survival rates on the whole. However, adjustment for metastatic status negates this difference. Patients with metastatic CRCC show a high prevalence of sarcomatoid features, predilection for liver metastases, no response to immunotherapy, and exhibit poor prognosis.