The risk of death from heart disease in patients with nonsmall cell lung cancer who receive postoperative radiotherapy: Analysis of the surveillance, epidemiology, and end results database

BACKGROUND. This study was designed to investigate whether the mortality from heart disease, a manifestation of intercurrent disease after postoperative radiotherapy (PORT), has decreased over time for patients with nonsmall cell lung cancer (NSCLC). METHODS. The 17-registry 1973 to 2003 dataset from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program was used to create a cohort of patients with NSCLC who had evidence of ipsilateral lymph node involvement diagnosed from 1983 to 1993 and who underwent pnuemonectomy/lobectomy (n = 6148 patients). Heart disease mortality was the primary endpoint: Deaths from other causes were censored, and surviving patients were censored at 10 years. The independent variable was PORT use, and adjustment variables included age at diagnosis, sex, race, year of diagnosis, laterality, location, histology, and the operation performed. RESULTS. Multivariate analysis revealed that PORT use was associated with an increase in heart disease mortality (hazards ratio [HR], 1.30; 95% confidence interval [95% CI], 1.04-1.61; P = .0193) along with older age, male sex, African-American race, and earlier year of diagnosis. The association was confirmed in the cohort that was diagnosed from 1983 to 1988 (HR, 1.49; 95% CI, 1.11-2.01 [P = .0090]) but not for the cohort that was diagnosed from 1989 to 1993 (HR, 1.08; 95% CI, 0.79-1.48 [P = .6394]). CONCLUSIONS. The results from this study demonstrated that the risk of heart disease mortality associated with PORT has declined in more recent years. This may be secondary to improvements in the treatment planning and delivery of thoracic radiotherapy. Properly designed, prospective, adjuvant trials will be needed to verify these findings.