Interferon-α-based immunotherapy in metastatic renal cell carcinoma patients with the primary tumor in situ.

OBJECTIVE: We reviewed the outcomes of metastatic renal cell carcinoma patients with the primary tumor in situ who initially underwent interferon-α-based immunotherapy to evaluate the effect of this therapy on metastatic sites as well as primary kidney tumor and survival.

METHODS: Thirty-one patients, for whom upfront cytoreductive nephrectomy was considered to be inappropriate because of poor performance status and far-advanced disease, were the subject of the present study. Tumor response and reduction in the size of metastatic sites and primary kidney tumor were assessed. Overall survival distributions were estimated using the Kaplan-Meier method with the significance determined using the log-rank test.

RESULTS: Partial response was observed in 11 patients, yielding an overall response rate of 35%. Seventeen patients had regression or stabilization of metastatic sites, while progression of metastatic sites was observed in the remaining 14 patients. Regarding the maximum response of primary kidney tumor, a reduction in kidney primary tumor size was observed in 42% of the patients and the mean reduction rate in these patients was 18.2% (range: 3-36%). Furthermore, the reduction in the size of metastatic sites was significantly associated with that in the size of primary kidney tumor (R(2)= 0.432, P< 0.0001). The median survival for the 31 patients was 17 months. The median survival was 42 months in patients with regression or stabilization of metastatic sites and 7 months in those without (P< 0.001).

CONCLUSIONS: The present study suggests that metastatic sites as well as primary kidney tumor respond to interferon-α-based immunotherapy in metastatic renal cell carcinoma patients with primary tumor in situ.