OUTLINE: This is a dose escalation study of nitrocamptothecin. Patients receive oral nitrocamptothecin on days 1-3 and oral etoposide on days 4-5 each week. Treatment continues in the absence of disease progression or unacceptable toxicity. Cohorts of 3-6 patients receive escalating doses of nitrocamptothecin until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 6 patients experience dose limiting toxicities. Patients are followed every 4 weeks until toxicities resolve.