Carboplatin plus paclitaxel in unknown primary carcinoma: a phase II Hellenic Cooperative Oncology Group Study

To evaluate the efficacy of the carboplatin/paclitaxel combination in patients with carcinoma of unknown primary site (CUP).

Seventy-seven consecutive CUP patients (45 women and 32 men; median age, 60 years) were treated with carboplatin at target area under the curve 6 mg/mL/min followed by paclitaxel 200 mg/m(2) as a 3-hour infusion and granulocyte colony-stimulating factor from days 5 to 12. Treatment courses were repeated every 3 weeks to a maximum of eight cycles. Forty-seven patients had adenocarcinomas, 27 had undifferentiated carcinomas, and three had squamous cell carcinomas. Thirty-three patients presented with liver, bone, or multiple organ metastases, 23 with predominantly nodal/pleural disease, and 19 (16 women) with peritoneal carcinomatosis.

The overall response rate by intent-to-treat analysis was 38.7% (95% confidence interval, 27.5% to 49.9%). There were no differences in response between adenocarcinomas and undifferentiated carcinomas, but efficacy varied among clinical subsets. The response rates and median survival times in the three clinically defined subsets were 47.8% and 13 months, respectively, for patients with predominantly nodal/pleural disease, 68.4% and 15 months, respectively, in women with peritoneal carcinomatosis, and 15.1% and 10 months, respectively, in patients with visceral or disseminated metastases. Chemotherapy was well-tolerated.

Carboplatin plus paclitaxel combination chemotherapy is effective in patients with predominantly nodal/pleural metastases of unknown primary carcinoma and in women with peritoneal carcinomatosis. However, in patients with liver, bone, or multiple organ involvement, the combination offers limited benefit. The investigation of novel treatment approaches is highly warranted for this group of patients.