Supplementary Material for: 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.