Prolonged administration of oral etoposide in patients with relapsed or refractory small-cell lung cancer: a phase II trial. Twenty-two patients with recurrent small-cell lung cancer (SCLC) were treated with single-agent etoposide 50 mg/m2/d by mouth for 21 consecutive days. Eleven patients had received previous chemotherapy with cyclophosphamide, doxorubicin, and vincristine (CAV) or etoposide (CAE) or both (CAVE). Four of the latter patients also received salvage treatment with cisplatin and etoposide (EP). Nine patients had been treated with EP as induction therapy, while two patients had received high-dose cyclophosphamide, etoposide and cisplatin (HDCEP). Altogether, 18 patients had received previous intravenous etoposide. The median time off chemotherapy was 4.5 months (range, 1 to 28.9 months). Ten patients (45.5%; 95% confidence interval [CI], 27% to 65%) achieved a complete or partial response. Responses were most common in patients who had responded to previous chemotherapy and who had not received any treatment in the 90 days before initiation of oral etoposide. Median response duration was 4 months (range, 1.5 to 9.5 months) and median survival was 3.5+ months (range, 1.0 to 15+ months). Leukocyte and platelet nadirs were 1,800/microL and 160,000/microL, respectively, during cycle 1 of treatment and occurred between days 21 and 28. Overall, total leukocyte count decreased to less than 1,000/microL during 10 of 56 cycles (18%). Five patients required six hospitalizations for neutropenia and fever. There were two toxic deaths due to sepsis. Platelet counts less than 50,000/microL occurred in 14 cycles (25%). Alopecia developed in all patients; gastrointestinal toxicity was uncommon. This schedule of etoposide administration warrants further study in combination with other active agents in previously untreated patients with SCLC. 