Crizotinib is being tested to see if it helps people with stage IB-IIIA non-small cell lung cancer (NSCLC) with ALK fusion mutations after surgery. ALK is a protein that can help cancer cells grow. Crizotinib works by blocking this protein. In this study, patients will be randomly assigned to receive Crizotinib or be under observation. Crizotinib is taken by mouth twice daily for up to two years, unless the disease worsens or side effects are too severe.

Key Points:

• Participation in the study can last up to two years with follow-ups every 6-12 months.
• Participants may receive Crizotinib or be under observation, based on random assignment.
• The study collects blood and tumor samples for future research.

Eligibility includes having had surgery for lung cancer and testing positive for ALK mutations. Women cannot be pregnant or breastfeeding, and both men and women must use effective birth control. Patients must also be free of serious health issues and not currently taking certain medications. They must have recovered from previous treatments and meet specific blood test criteria.