Recent survival trends in high-grade neuroendocrine neoplasms and lung cancer

BACKGROUND: Poorly differentiated neuroendocrine neoplasms (pdNEN) are a rare cancer entity, treatment of which is to a great part informed by studies on the much more common small-cell lung cancer (SCLC). OBJECTIVE: To reveal and compare recent survival trends for pdNEN and SCLC in an authorative, population-based database. METHODS: Using the Surveillance, Epidemiology, and End Results 18 database, 3,482 digestive tract pdNEN and 30,383 SCLC diagnosed from 2000 through 2015 were analyzed in detail. RESULTS: Whereas changes in one- and 2-year relative survival in pdNEN were small, improvements in median survival appeared consistent and relevant. For example, median survival (95% CI) for distant disease pdNEN diagnosed in 2000-2004, 2005-2009, and 2010-2015 was 4.6 (3.8-5.4), 5.6 (4.5-6.7), and 6.4 (5.4-7.5) months. Changes in SCLC survival during the study period overall were even more limited, which - in the case of distant disease - meant that survival disadvantages of patients with pdNEN as compared to SCLC disappeared during the study period. Unfortunately, relevant improvements in year-wise conditional survival after the first year since diagnosis essentially were restricted to localized pdNEN and localized SCLC. CONCLUSIONS: Our results should stipulate further research, in particular, of the pdNEN-SCLC relationship. They will also be helpful in patient care and communication, providing the first conditional survival details in this context, a highly patient-relevant outcome.