Adding Radiotherapy to Adjuvant Chemotherapy Does Not Improve Survival of Patients With N2 Lung Cancer

The management of N2 non-small cell lung cancer (NSCLC) found at operation is controversial. Current guidelines recommend adjuvant chemotherapy or adjuvant chemoradiotherapy. We evaluated whether adjuvant chemoradiotherapy was associated with improved survival compared with adjuvant chemotherapy in patients with N2 NSCLC after complete resection.

We queried the National Cancer Database for all patients with clinical N0, pathologic N2 NSCLC who did not receive preoperative therapy and underwent complete (R0) surgical resection, followed by adjuvant chemotherapy or chemoradiotherapy. We performed propensity matching to create a well-balanced cohort of patients with respect to age, sex, race, comorbidities, treating facility, tumor size, year of diagnosis, and number of positive nodes. Survival was examined using the Kaplan-Meier method with log-rank analysis.

We identified 2,031 eligible patients; 1,149 (56.6%) received adjuvant chemotherapy and 882 (43.4%) received chemoradiotherapy. Patients in the unmatched cohort who received chemoradiotherapy tended to be younger (64.2 vs 65.4 years) and to have a comorbidity score of 0 (57.5% vs 52.1%). Median survival was similar (3.9 years with chemoradiotherapy vs 3.8 years with adjuvant chemotherapy, p = 0.518). We then identified 848 well-matched pairs and again did not detect differences in median survival (3.9 years with chemoradiotherapy vs 3.8 years with adjuvant chemotherapy, p = 0.705).

In a large database study, the addition of radiotherapy to adjuvant chemotherapy after resection of N2 NSCLC was not associated with improved survival. Until more definitive data are available, consideration should be given to treating patients with N2 disease detected at resection with adjuvant chemotherapy only.