Clinical characteristics and survival of lung cancer patients associated with multiple primary malignancies.

To investigate the characteristics and survival of lung cancer patients with additional malignant primary cancers.Records of lung cancer patients newly diagnosed in Shanghai Pulmonary Hospital between January 2000 and January 2010 were retrospectively reviewed. Patients with second primary lung cancer and those with lung cancer only were included for detailed analysis.Of 27642 newly diagnosed lung cancer patients, 283 patients (1.02%) suffered previous additional primary cancers. Compared with single primary lung cancer, patients with secondary lung cancer associated other primary cancers were more often women (female to male ratio 1:1.72 vs 1:2.58, P = 0.018), older (64.2 vs 60.5 years old, P<0.001), more squamous cell type (30.7% vs 20.5%, P = 0.004), less small cell (3.9% vs 15.5%, P