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

Objectives To investigate the characteristics and survival of lung cancer patients with additional malignant primary cancers. Methods 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. Results 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<0.001) type, at earlier stages (17.7% vs 11.0% for stage I, P = 0.014), and more frequently with family history of cancers (7.8% vs 3.9%, P = 0.038). The most common previous primary cancers observed were colorectal (22.0%), breast (18.4%), gastric (14.4%) and larynx cancers (11.9%). Approximately 42.9% of patients were diagnosed with lung cancer 2 to 6 years after diagnosis of initial primary cancers. The survival of patients with secondary lung cancer associated other malignancies was not significantly different from those with single lung cancer (P = 0.491), while synchronous multiple primary malignancies showed worse prognosis compared with those with metachronous ones or single lung cancer (p = 0.012). Conclusion The possibility of second primary lung cancer should always be considered during the follow-up of related cancer types, especially those with family history of cancers. Patients with secondary lung cancer associated other primary malignancies have non-inferior survival than those with single lung cancer.