Does migration to smaller size for localized lung adenocarcinomas predict improved lung cancer-specific survival?

Background: Clinical trials have demonstrated improved survival among patients diagnosed with non-small cell lung cancer detected using spiro-CT screening. We identified increasing proportions of localized lung adenocarcinomas that were less than 18 mm at diagnosis, with the reverse trend for 18-32 mm diameter malignancies in California from 2001-2012. Migration to smaller size at diagnosis was concomitant with increased utilization of CT-imaging, suggesting survival benefits attributable to improved imaging technology. The state-of-the-art, California Cancer Registry, captures information on cancer occurrence in the diverse statewide population (38 million).

Objectives: We sought to compare survivals for localized lung adenocarcinomas that were less than 18 versus 18-32 mm diameter at diagnosis.

Methods: All localized adenocarcinomas of the lung diagnosed among California residents (2001-2012) were identified and classified as 1-17 (small) versus 18-32 mm (large) diameter. Cox proportional hazards analysis was used to assess lung cancer-specific mortality more than 60 days after diagnosis of small versus large tumor size.

Results: Reduced lung cancer mortality hazard was evident for small versus large lung adenocarcinomas, independent of other covariates. Other predictors of reduced mortality hazards included female gender and Hispanic versus non-Hispanic white race/ethnicity. Single versus married status predicted higher mortality hazard, increasing age and SES showed increasing mortality trends, with the reverse trend measured for diagnosis year.

Conclusions: These findings reveal a significant reduction in mortality hazard for small versus large localized lung adenocarcinomas during a period of migration to smaller tumor size at diagnosis that is concomitant with increased utilization of CT-imaging.