Trends in Cardiac Mortality in Patients With Locally Advanced Non-Small Cell Lung Cancer

To use the Surveillance, Epidemiology, and End Results (SEER) database to compare cardiac-specific mortality (CSM) between left- and right-sided locally advanced non-small cell lung cancer (LA-NSCLC) patients treated with definitive radiation therapy; and to stratify these patients over fixed time intervals to assess for differences in events by treatment era.

The SEER database was queried for patients with stage III NSCLC who received radiation therapy to compare CSM between left- and right-sided primary cases at 5 time intervals: 1988-1992, 1993-1997, 1998-2002, 2003-2007, and 2008-2012. Cumulative incidence of CSM was compared between left- and right-sided patients using Gray's test. The multivariate Fine and Gray competing risk model was used to compare CSM while accounting for other-cause mortality.

Of 884,610 lung cancer patients, 52,624 met inclusion criteria; of these, 31,549 (60%) were right-sided and 21,075 (40%) were left-sided. When evaluating CSM in each of the 5 time periods, the overall incidence of CSM decreased over time. There was a statistically significant (P<.05) difference based on laterality in all time periods except 1988-1992 (P=.14). The subdistribution hazard ratio for CSM based on disease laterality in all time periods was 1.30 (95% confidence interval 1.18-1.42) and did not discernibly differ by time interval. On multivariate analysis using the Fine and Gray competing risk model, left-sided laterality independently predicted for CSS from 1993 to 2007 (P<.05).

Cardiac-specific mortality has decreased over time, and left-sided disease independently predicted for CSS during 1993-2007 but not 2008-2012. The time course of cardiac mortality seems to be early, consistent with other studies. These findings underscore the importance of minimizing cardiac irradiation during radiation treatment planning.