One-hour paclitaxel, carboplatin, and extended-schedule etoposide in the treatment of carcinoma of unknown primary site.

This phase II study was conducted to evaluate the efficacy and toxicity of a novel chemotherapy combination that included paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), carboplatin, and extended-schedule etoposide for the treatment of patients with carcinoma of unknown primary site. Fifty-five patients were treated with the following regimen, administered every 21 days: paclitaxel 200 mg/m2 by 1-hour intravenous infusion, day 1; carboplatin at an estimated area under the concentration-time curve of 6.0, day 1; and etoposide 50 mg alternating with 100 mg orally, days 1 through 10. The following histologies were included: well-differentiated adenocarcinoma, 30 patients; poorly differentiated carcinoma or poorly differentiated adenocarcinoma, 21 patients; poorly differentiated neuroendocrine carcinoma, three patients; and squamous carcinoma, one patient. All patients had advanced tumor, and two thirds had two or more organ systems involved with cancer. Twenty-five of 53 evaluable patients (47%) had major objective responses to treatment. Seven patients (13%) had complete responses. Response rates were similar in patients with well-differentiated adenocarcinoma versus poorly differentiated carcinoma (45% and 48%, respectively). Median survival for the entire group was 13.4 months. The regimen was well tolerated, with only seven hospitalizations for treatment of fever associated with neutropenia and no treatment-related deaths. This combination regimen is very active and well tolerated in patients with carcinoma of unknown primary site. Response rates and survival in this multicenter community-based trial appear superior to all previously studied empiric regimens. This regimen is substantially less toxic and easier to administer than the cisplatin-based regimens. Should this efficacy be confirmed in other trials, this treatment should be considered standard initial therapy for patients with carcinoma of unknown primary site.