Taxane-based chemotherapy for patients with carcinoma of unknown primary site

The purpose of this study was to determine the long-term follow-up on survival of patients with carcinoma of unknown primary site treated with taxane-based chemotherapy in a multicenter community-based setting.

Patients were treated with three sequential phase II trials between 1995 and 1998 as follows: Study I: paclitaxel 200 mg/m2 intravenously (i.v.) Day 1, carboplatin AUC = 6 i.v. Day 1, and oral etoposide 50 mg daily alternating with 100 mg daily days 1-10 every 3 weeks; Study II: docetaxel 75 mg/m2 i.v. Day 1, cisplatin 75 mg/m2 i.v. Day 1, repeated every 3 weeks; Study III: docetaxel 65 mg/m2 i.v. Day 1, carboplatin AUC 6 i.v. Day 1, repeated every 3 weeks. A total of 144 patients (71 on Study I, 26 on Study II, 47 on Study III) were treated (45% had well differentiated carcinoma, 48% had poorly differentiated carcinomas, and 6% poorly differentiated neuroendocrine tumors). The majority of the patients had multiple sites of metastatic disease.

Thirty-six percent of all evaluable patients responded to therapy (27% partial and 9% complete responses). The median survival was 10 months with 1-, 2-, 3-, and 4-year survivals of 42%, 22%, 17%, and 17%, respectively. Follow-up ranges from 11 to 50 months. Women survived significantly longer than men. Thirty-one patients remain alive and 14 are progression-free. The primary toxicity was leukopenia with the carboplatin regimens and nausea and vomiting with the cisplatin regimen. A review of the survival of several large previously reported series of patients was compared to results after taxane-based chemotherapy. A compelling argument is made that chemotherapy is superior to best supportive care alone and that taxane-based chemotherapy is superior to other forms of chemotherapy. However, prospective randomized trials will be necessary to definitively demonstrate the superiority of this treatment compared to other therapies for these patients.

Taxane-based chemotherapy for patients with carcinoma of unknown primary site appears to be clinically beneficial and is associated with long-term survival for a minority of patients at 2-, 3-, and 4-year follow-up.