The potential role of postoperative radiation therapy (PORT) for patients who have completely resected, stage III nonsmall cell lung cancer (NSCLC) with N2 disease remains controversial. By using population-based data, the authors of this report compared the survival of a concurrent cohort of elderly patients who had N2 disease treated with and without PORT.
By using the Surveillance, Epidemiology, and End Results (SEER) registry linked to Medicare records, 1307 patients were identified who had stage III NSCLC with N2 lymph node involvement diagnosed between 1992 and 2005. Propensity scoring methods and instrumental variable analysis were used to compare the survival of patients who did and did not receive PORT after controlling for selection bias.
Overall, 710 patients (54%) received PORT. Propensity score analysis indicated that PORT was not associated with improved survival in patients with N2 disease (hazard ratio [HR], 1.11; 95% confidence interval [CI], 0.97-1.27). Analyses that were limited to patients who did or did not receive chemotherapy, who received intermediate-complexity or high-complexity radiotherapy planning, or adjusted for time trends produced similar results. The instrumental variable estimator for the absolute improvement in 1-year and 3-year survival with PORT was −0.04 (95% CI, −0.15 to 0.08) and −0.08 (95% CI, −0.24 to 0.15), respectively.
The current data suggested that PORT is not associated with improved survival for elderly patients with N2 disease. These findings have important clinical implications, because SEER data indicate that a large percentage of elderly patients currently receive PORT despite the lack of definitive evidence about its effectiveness. The potential effectiveness of PORT should be evaluated further in randomized controlled trials. Cancer 2012. © 2012 American Cancer Society.