Determining carboplatin/etoposide dosage in extensive stage small-cell lung cancer (SCLC)

In order to define the maximum tolerance level of combined carboplatin/etoposide dosage, patients with extensive stage small-cell lung cancer (SCLC) were treated with a fixed dose of carboplatin (300 mg/m2 iv on day 1) and escalating doses of etoposide starting with 80 mg/m2 iv on days 1-3. Five patients were given this starting and every following dose level. The daily dose of etoposide was increased in increments of 20 mg/m2 iv until severe myelosuppression occurred in 3 of 5 patients. Leuko- or thrombocytopenia WHO grade 3 or 4 occurred in 0/5 of the patients at the dose levels of 80 and 100 mg/m2, in 1/4 of the patients at the level of 120 mg/m2, in 2/5 of the patients at a level of 140 mg/m2, and 3/5 patients at a level of 160 mg/m2. Thus, increase in dosage was stopped at an etoposide dose of 160 mg/m2. Other side effects were mild and consisted predominantly of nausea and vomiting in 14/25 of the patients. The overall response rate was 40% with a 12% complete remission rate, median survival was 9.3 months and median progression-free survival totalled 4.3 months. These results indicate that combined carboplatin/etoposide is a well tolerated regimen in extensive-stage SCLC, with response rates comparable to those of other standard protocols. Using treatment intervals of 4 weeks the recommended dose of etoposide in combination with 300 mg/m2 carboplatin was identified as 140 mg/m2 iv for 3 consecutive days.