The purpose of this study is to find out if giving oral HYCAMTIN to patients with relapsed small cell lung cancer benefits them. The study will compare how long patients live when they are given therapy to make them feel better (active symptom control) to the length of time patients live when they are also receiving oral HYCAMTIN.

Inclusion Criteria:

• Received one prior chemotherapy regimen only.
• Documented partial or complete response to first-line therapy.
• Documented relapse of limited or extensive SCLC at least 45 days after the cessation of first-line chemotherapy.
• Not considered suitable for further intravenous chemotherapy.
• Considered to have adequate bone marrow reserve.
• Performance Status of 0, 1 or 2.

Exclusion Criteria:

• Pregnant or lactating.
• Received more than one prior regimen of chemotherapy.
• Uncontrolled vomiting.
• Brain metastases.
• Active uncontrolled infection.
• Received previous treatment with HYCAMTIN.
• Received an investigational product within 30 days.