Metastatic renal carcinoma long-term survivors treated with s.c. interferon-alpha and s.c. interleukin-2

The aim of this retrospective analysis was to identify common features of long-term survivors among 218 advanced renal cell carcinoma patients sequentially entered on subcutaneous-recombinant-cytokine- based therapies between 1988 and 1993.

All patients were treated with subcutaneous (s.c.) interferon-alpha2a (IFN-alpha2a) and s.c. interleukin-2 (IL-2) alone (n = 98 pts) or in combination with intravenous (i.v.) 5-fluorouracil (5-FU) (Atzpodien regimen; n = 120 pts); those patients who survived more than 10 years were classified as long-term survivors.

Thirteen patients (6.3%) were identified as long-term survivors with a median follow-up of 141 months (range, 122-174 months). According to a validated model of known clinical predictors, the long-term survivor group consisted of 6 low-risk, 5 intermediate-risk, and 2 high-risk patients, respectively. Within their clinical course, 9 longterm survivors achieved a complete response with a median duration of 141 months (range, 91-161 months), 1 patient yielded a partial remission, and 3 patients achieved stable disease. Maximum response was observed between 2 and 40 months after treatment initiation (median, 4 months), while treatment time to maximum response ranged from 2 to 14 months (median, 4 months). There was no correlation between treatment time and maximum response. Overall, long-term survivors underwent treatment for 4 and up to 80 months (median, 8 months).

Our data suggest that long-term survival of metastatic renal carcinoma patients beyond 10 years is independent of known clinical risk factors and treatment time. However, long-term survival of cytokine-treated, advanced renal cell carcinoma (RCC) patients remains a rare event and, thus, emphasizes the need for further investigations toward more effective therapies.