Survival changes in patients with small cell lung cancer and disparities between different sexes, socioeconomic statuses and ages

Abstract

Small cell lung cancer (SCLC), as a proportion, makes up only 15-17% of lung cancer cases. The development of treatments for SCLC has remained stagnant for decades, and SCLC is expected to persist as a threat to human health. To date, no publications based on large populations have been reported. We calculated survival changes in patients with SCLC during each decade between 1983 and 2012 to determine the roles of race, sex, age, and socioeconomic status (SES) on survival rates based on the Surveillance, Epidemiology, and End Results (SEER) registries. In total, 106,296 patients with SCLC were identified, with the overall incidence per 100,000 decreasing each decade from 9.6 to 7.8 to 5.8. The median survival for SCLC remained 7 months, and the 12-month relative survival rates (RSRs) remained relatively stable at 32.9%, 33.2% and 33.2% during each decade. The 5-year RSRs significantly improved from 4.9% to 5.9% to 6.4% during each decade, but remained extremely low. In addition, a narrowing of the survival gaps among SES groups and stable survival gaps between sexes were observed. Although the incidence of SCLC decreased during each decade, the overall survival remained relatively stable, highlighting the urgency of developing novel treatments and the importance of prevention and early detection.

Figure 1

Summary incidences of patients diagnosed as having SCLC between 1983 and 2012 at the original nine SEER sites. Incidence (a) and number (b) of SCLC cases are shown by age group (total and ages 0–34, 35–49, 50–64, 65–79, and 80+ years) and calendar period. Incidence and number of SCLC cases are grouped by sex (c,d), SES (e,f), and race (g,h), respectively.

Figure 2

Trends in five-year relative survival rates (a) and Kaplan-Meier survival analyses (b) for patients with SCLC at 18 SEER sites between 1983 and 2012 according to age group (total and ages 0–34, 35–49, 50–64, 65–79, and 80+ years) and calendar period.

Figure 3

12-month (a), 60-month (b) relative survival rates and Kaplan-Meier survival analyses from 1983 to 2012 (c) for patients with SCLC at 18 SEER sites according to sex by age group (total and ages 0–34, 35–49, 50–64, 65–79, and 80+ years).

Figure 4

12-month, 36-month and 60-month relative survival rates by race (a) and SES/county-level poverty rates (b) and Kaplan-Meier survival analyses according to race (c) and SES/county-level poverty rates (d) for patients with SCLC at 18 SEER sites from 1983 to 2012.