Impact of histology on the treatment outcome of metastatic or recurrent renal cell carcinoma

Among 107 renal cell carcinoma (RCC) patients with histopathologic subtype diagnosis who were treated at Albert Einstein Cancer Center with cytokines over a 10-year period, seven patients had sarcomatoid histology, 63 had cle ar cell carcinoma, and 10 patients had mixed histology (sarcomatoid and cle ar cell). Regardless of their histology, patients with a disease free inter val of 2 years or more had significantly better survival. Hone of the patie nts with sarcomatoid histology responded to therapy. However, several patie nts with mixed and clear cell histology achieved partial or complete respon ses following high dose Interleukin-2 (IL-2) therapy. The median survival o f patients with sarcomatoid histology was the shortest (13.8 months), whils t that of patients with mixed and clear cell histology was much longer (34. 8 months and 39.1 months, respectively). This result was statistically sign ificant in both univariate and multivariate survival analysis (P < 0.001 an d P < 0.01, respectively). Patients with mixed and clear cell histology had no significant difference in survival, and their median survival combined was significantly longer than that of patients with sarcomatoid histology ( P < 0.0001 in univariate analysis, P < 0.01 in multivariate analysis). This study suggests that survival with a diagnosis of RCC is predicted by tumor histology and disease free interval, and this impacts on the ability to re spond to standard therapy. Patients with mixed and clear cell histology res pond to cytokine therapy. Other therapies should be sought for patients wit h sarcomatoid RCC.