Survival Trends of Metastatic Lung Cancer in California by Age at Diagnosis, Gender, Race/Ethnicity, and Histology, 1990-2014

Background: We analyzed the survival trends for patients with metastatic lung cancer in California. Materials and Methods: We identified patients first diagnosed with primary lung cancer at distant (metastatic) stage in the California Cancer Registry between 1990 and 2014, with follow-up through end of 2015. Race/ethnicity was categorized into non-Hispanic white, non-Hispanic black, Hispanic, and Asian/Pacific Islander. One-year and 5-year relative survival rates were calculated overall and by age at diagnosis, gender, race/ethnicity, and histology during the study period. Joinpoint regression was used to evaluate the trends and to calculate the annual percentage changes (APCs). Results: A total of 186,156 adults were identified for analysis. Between 1990 and 2014, 1-year relative survival significantly improved from 18.4% to 29.4%, with most improvement observed between 1993 and 2012 (APC, 2.60%; 95% confidence interval, 2.41-2.79; P < .01). Five-year relative survival significantly improved from 2.2% to 5.0%, with an APC of 4.05% (95% confidence interval, 3.47-4.64; P < .01). All age groups experienced an improvement in survival rates. The greatest increases in relative survival were observed among females, Asian/Pacific Islanders, and patients with adenocarcinoma. Yearly survival rates increased for all histologic types over the study period, with adenocarcinoma having the most improvement after 2000. Conclusions: Survival for patients with metastatic lung cancer in California steadily improved during the 1990 to 2014 period, before the era of lung cancer screening and cancer immunotherapy. The greatest increase in relative survival was observed in those patients who have the most clinical benefit from the history- and biomarker-based precision oncology drugs during the study period.