Large cell neuroendocrine carcinoma of the lung: A population-based study.

e13122 Background: In 2015, the World Health Organization dissolved the category of non-small cell lung cancer (NSCLC) that was previously known as “large cell carcinoma” into adeno- or squamous cell carcinomas, with the exception of large cell neuroendocrine carcinoma (LCNEC), which is now grouped with other neuroendocrine carcinomas of the lung. There is limited data on the epidemiology and best treatment practices for this malignancy, and studies comparing prognosis with SCLC and NSCLC have been conflicting. Methods: We reviewed the epidemiology of LCNEC using data from the Surveillance, Epidemiology and End Results Program from 2010 – 2015. Demographical features and overall survival were compared with SCLC and NSCLC. Trends in incidence and mortality rates were observed from 2004 – 2015. Results: We analyzed 195,148 cases of lung cancer, including 1,681 (0.9%) cases of LCNEC. Age-adjusted incidence of LCNEC was 0.31 per 100,000 people and had increased by 50% over the period studied. This increased incidence was primarily the result of increased incidence of stage IV disease. LCNEC was more likely to present with brain metastasis at diagnosis (19.2%) than either SCLC (16.7%, p = .01) or NSCLC (13.0%, p < .001). Survival patterns for LCNEC mirrored NSCLC in stage I – III disease and SCLC in stage IV disease. After adjusting for other clinical and demographic variables, survival for LCNEC was not different than SCLC but worse than NSCLC (HR = 0.88 for NSCLC vs. LCNEC, p < .001). Survival rates for LCNEC and SCLC did not significantly change over the time period studied, whereas survival rates for NSCLC significantly improved. Consistent with our findings of increased incidence of LCNEC with no change in survival patterns, age-adjusted incidence-based mortality increased by two-fold over the time period studied. Conclusions: LCNEC generally has a worse prognosis than NSCLC and better than SCLC. LCNEC presents with brain metastases more frequently than SCLC. Incidence of LCNEC is consistently increasing in the U.S. Despite this, it remains poorly studied and prognosis for LCNEC has not improved with time. LCNEC has, therefore, become an increasing cause of lung cancer mortality in the American population.