Purpose: To evaluate the efficacy and toxicity of the novel chemotherapy combination that includes gemcitabine, carboplatin, and paclitaxel in the treatment of patients with carcinoma of unknown primary site.
Patients and methods: One hundred twenty patients were treated with the following regimen, administered every 21 days for a planned four courses: gemcitabine 1,000 mg/m(2) intravenously (i.v.) on days 1 and 8, carboplatin at an estimated area under the concentration-time curve of 5 mg min/mL i.v. on day 1, and paclitaxel 200 mg/m(2) i.v. on day 1. After four courses, stable and responding patients were given weekly paclitaxel 70 mg/m(2) i.v. for 6 weeks for three 8-week courses. All patients had relatively poor prognostic features. Sixty-three patients had well-differentiated adenocarcinoma, 56 patients had poorly differentiated carcinoma, and 104 patients had performance status of 0 or 1.
Results: Twenty-eight (25%) of 113 assessable patients (95% confidence interval, 22% to 30%) had major objective responses to treatment. Response rates were similar in the two major histologic types. Response rate did not seem to be improved by continued therapy with weekly paclitaxel. The median progression-free survival time was 6 months. Median survival for the entire group was 9 months, and the actuarial survival at 1 and 2 years was 42% and 23%, respectively.
Conclusion: Combination chemotherapy with gemcitabine, carboplatin, and paclitaxel followed by weekly paclitaxel is an active and tolerable treatment for patients with carcinoma of unknown primary site. The survival seen in this poor-prognosis group of patients in this multicenter community-based trial is notable and similar to other taxane-based regimens for these patients. Study of additional combinations or sequences of newer drugs, as well as the exploration of targeted biologic agents for patients with an identified target in their tumors, is warranted.