Changing Epidemiology of Elderly Small Cell Lung Cancer Patients over the Last 40 Years; a SEER Database Analysis

Background: Small cell lung cancer (SCLC) is a distinct clinical and pathological entity within the spectrum of lung cancer. It was observed that the relative age distribution of the disease changed over years.

Methods: Surveillance, epidemiology, and end results (SEER) database (1973-2013) was utilized to determine the incidence, presentation and treatment outcomes of elderly patients (>70 years) with SCLC. Join point regression analysis was then conducted to analyze age-adjusted trends in incidence for the elderly as well as the whole SCLC population. Survival analysis was conducted through Kaplan-Meier analysis. Clinicopathological characteristics and survival outcomes were compared between patients diagnosed at 70-79 years old and those older than 80 years old (octogenarian group).

Results: The proportion of elderly patients among all cases of SCLC increased from 23% in 1975 to 44% in 2010. Moreover, the proportion of elderly female patients among all cases of elderly SCLC increased from 25% in 1975 to 49% in 2010. When categorizing patients into four subgroups "70-74," "75-79," "80-84," and "85+", there was a trend toward a lower cancer-specific survival with increasing age (P < .0001). A limited improvement in 5 year survival was observed during the study period and it is less apparent as the age increases.

Conclusion: The proportion of elderly patients among all cases of SCLC has increased over the past 40 years. Further studies are needed to better select appropriate treatments for this subset of patients.