Failure to confirm major objective antitumor activity for streptozocin and doxorubicin in the treatment of patients with advanced islet cell carcinoma

Abstract

The combination regimen of streptozocin plus doxorubicin is the current standard chemotherapeutic treatment of symptomatic or progressing metastatic islet cell carcinoma. This regimen previously has been reported to have a major objective response rate of 69% in a randomized cooperative group trial. However, the authors believed that this favorable response rate was not consistent with their institutional experience at Memorial Sloan-Kettering Cancer Center (MSKCC). The authors retrospectively reviewed the records of all islet cell carcinoma patients under care at MSKCC who were treated with streptozocin plus doxorubicin since the publication of the study mentioned earlier. Sixteen such patients treated between February 1992 and February 1998 were identified. Their clinical characteristics, sites of measurable disease, response to treatment, time to treatment failure, and survival status were reviewed. All patients were treated with the starting doses as outlined by the published cooperative group report. All had bidimensionally measurable disease on computed tomography (CT) scans. Only 1 of 16 patients (6%; 95% confidence interval, 0-30%) achieved a major objective response by standard CT response criteria, with response ongoing during treatment at 18 months. Nine patients (56%) had stable disease while receiving treatment (range of treatment, 2-17+ months). Six patients (38%) had progression of disease as their best response while receiving treatment. The median overall survival of this patient group had not yet been reached at last follow-up, with > 60% of patients alive with follow-up ranging from 10-67+ months. A retrospective analysis of the authors' 6-year experience with the combination of streptozocin plus doxorubicin in patients with islet cell carcinoma failed to confirm the high objective response rate previously reported for this regimen. There remains an urgent need for improved chemotherapeutic alternatives for patients with this disease.