Abstract
BACKGROUND: Patients with non-small cell lung cancer (NSCLC) and a prior or synchronous second malignancy are generally excluded from clinical trials. Therefore, little is known on prevalence and prognosis of these patients. METHODS: 1252 patients diagnosed with NSCLC in our center from 2006 to 2017 were studied. Overall survival (OS) of patients with a prior or synchronous malignancy was compared to controls including case-control analysis. RESULTS: 158 patients (12.6%) had a prior malignancy. The most common sites were prostate (17%), breast (16%), gastrointestinal tract (12%), head and neck (11%), bladder (10%), and lung (8%). Compared to controls, patients with prior malignancy were older (71.3 vs. 67.5 years), but had otherwise better prognostic characteristics (stage I-III 63 vs. 53%). Survival was identical compared to controls [hazard ratio (HR) 1.017, CI 0.776-1.333]. A further 3.5% of patients had a synchronous malignancy including 34% prior lung cancer. Patients with a synchronous malignancy had an earlier stage (I-III 84%), and had longer median OS in unselected patients (38.6 vs. 16.2 months, p = 0.021). However, the case-control analysis showed similar OS [hazard ratio (HR) 0.899, CI 0.497-1.621]. CONCLUSIONS: Prior or synchronous second malignancies are common at diagnosis of NSCLC. The sites reflect the high proportion of smokers in the population. The earlier stage of NSCLC with a second malignancy might be attributed to chance finding of NSCLC during follow-up. The second malignancy does not affect OS of NSCLC. Therefore, the exclusion of patients with second malignancies from NSCLC trials should be reconsidered.