3. Patients with multiple primary lung tumors (defined below) are eligible: a) synchronous tumors (diagnosed within 6 months [mo]), *different histology, *same histology, *second tumor in different lobed or lung; b) metachronous tumors (diagnosed >6 mo apart), *different histology, *same histology, **second tumor in different lobe or lung, **tumor-free interval of at least 4 years (y).