Post-Operative Radiation Therapy Improves Overall Survival in NSCLC Patients

Author(s):

Patients with NSCLC who received postoperative radiation therapy lived 4 months longer on average than patients who did not receive radiation but who had the same disease site, tumor histology, and treatment criteria, according to a large retrospective study.

John L. Mikell, MD

Patients with non—small cell lung cancer (NSCLC) who received postoperative radiation therapy (PORT) lived 4 months longer on average than patients who did not receive radiation but who had the same disease site, tumor histology, and treatment criteria, according to a large retrospective study. Limited data indicate that PORT may be beneficial for patients with involved N2 nodes.

“These results reinforce the value of PORT for NSCLC patients with involved mediastinal lymph nodes. Our data indicate that with modern radiotherapy equipment and treatment techniques, PORT can improve survival for these patients,” said John L. Mikell, MD, the study’s lead author. Mikell, chief resident in the Department of Radiation Oncology at Emory University Winship Cancer Institute in Atlanta, presented the research in a poster session at the 2014 Chicago Multidisciplinary Symposium in Thoracic Oncology.

For the study, researchers reviewed records from the National Cancer Data Base (NCDB) of patients diagnosed with NSCLC who had undergone surgery, had pathologically involved N2 nodes, and had received adjuvant chemotherapy. The NCDB is a joint endeavor of the Commission on Cancer of the American College of Surgeons and the American Cancer Society, and the records reviewed here cover the period 2004-2006.

Patients were excluded from the review if they had positive margins, incomplete survival data, a histology report other than NSCLC, and were naïve to adjuvant chemotherapy. Patients were also excluded if they had been treated with Cobalt-60, non-beam radiotherapy, and neoadjuvant therapy.

Overall, 2115 patients were eligible for analysis. Investigators identified 918 (43.4%) who received PORT and 1197 (56.6%) who did not. Patients who received PORT had a higher median survival time (42 months) compared with 38 months in patients who did not. This effect was significant in multivariable and Cox models (HR = 0.87, 95% CI 0.78-0.98, P =.026, and HR = 0.89, 95% CI 0.79-1.00, P = .046, respectively). Inverse probability of treatment weighting using the propensity score was also implemented to reduce biased treatment selection.

On multivariable analysis, female gender, adenocarcinoma histology, higher income, urban/rural setting versus metro area, lower T stage, 1-2 involved lymph nodes versus ≥3, higher number of examined lymph nodes, and younger age were associated with improved overall survival (P = .05). Investigators found no direct relation between the effects of PORT and the number of involved lymph nodes.

“The data in this study, the largest, most recent cohort of patients with involved mediastinal nodes treated with chemotherapy, reinforce that PORT should be considered in addition to chemotherapy following resection of NSCLC,” said Mikell.

Mikell JL, Gillespie TW, Hall WA, Nickleach DC, Liu Y, Lipscomb J, et al. Post-operative radiotherapy (PORT) is associated with better survival in non-small cell lung cancer with involved N2 lymph nodes. Presented at: 2014 Multidisciplinary Symposium in Thoracic Oncology; October 30-November 1, 2014; Chicago, IL. Abstract 128.

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