The changing landscape of small-cell lung cancer.

Abstract

e20634 Background: Small-cell lung cancer (SCLC) is an aggressive histologic subtype of lung cancer with distinct biology and clinical course. The aim of this study is to investigate the trends in demographics and outcomes. Methods: We queried the Surveillance, Epidemiology, and End Results (SEER) database to assess the incidence, demographics, and survival for SCLC using SEER 8 (8 registries), which include data from 1975 to 2019. The pattern of metastases was evaluated using SEER 17 from 2010 to 2019. Jointpoint analysis was used to calculate the trends in annual percentage change according to year of diagnosis. Results: There were 530,198 patients with lung cancer, including 73,362 (13.8%) patients with SCLC in the SEER 8. The percentage of SCLC among all lung tumors progressively increased from 13.3% in 1975 to a peak of 17.5% in 1986, followed by steadily decrease since 1990, reaching 11.1% in 2019. The incidence per 100,000 population increased from 9.5 in 1975 to 15.3 in 1986 followed by a gradual decline to 6.5 in 2019. Among patients with SCLC included in SEER 8, demographic changes from 1975-1979 to 2015-2019 included increased median age at diagnosis from 63 years to 69 and increased percentage of women from 31.4% to 51.2%. The percentage of patients with stage IV increased from 56.9% to 63.8% from 1995-1999 to 2000-2004, and to 69.5% in 2010-2014 without further increase. Among the 55,035 patients with SCLC in SEER 17 from 2010 to 2019, the most common sites of metastasis at diagnosis were mediastinal lymph nodes (69.9%) liver (30.5%), bone (22.8%), and brain (15.8%). The median, 1-year, and 5-year overall survival increased from 6 months, 23%, and 3.6% respectively in 1975-1979 to 7 months, 30.8%, and 6.8% respectively in 2010-2019 (P < 001). Conclusions: The incidence of SCLC in the United States reached a peak in 1985 to 1989 followed by a gradual decline. Demographic changes included an increased median age at diagnosis and the percentage of women, which surpassed men in the last study period. There was also an increase in the percentage of stage IV. The improvement in 5-year OS has been statistically significant but clinically modest.