Sequential Versus Concurrent Chemoradiation Therapy by Surgical Margin Status in Resected Non-Small Cell Lung Cancer

Background: Postoperative chemoradiotherapy (CRT) for non-small cell lung cancer (NSCLC) can be delivered sequentially (sCRT) or concurrently (cCRT). Without high-volume data, current guidelines recommend either option for patients with negative margins (M-) and cCRT for those with positive margins (M+). In this study, survival was compared between sCRT versus cCRT for M- and M+ disease; survival in patients who underwent sCRT was also assessed with chemotherapy-first versus radiotherapy (RT)-first. Methods: The National Cancer Database was queried for patients with primary NSCLC undergoing surgery followed by CRT. Patients were excluded if they received neoadjuvant chemotherapy or RT. Both M- and M+ (including R1 and R2) subcohorts were evaluated. Multivariable logistic regression ascertained factors associated with cCRT delivery. Kaplan-Meier analysis evaluated overall survival (OS); Cox proportional hazards modeling determined variables associated with OS. Propensity score matching aimed to address group imbalances and indication biases. Results: Of 4,921 total patients, 3,475 (71%) were M-, 1,446 (29%) were M+, 2,271 (46%) received sCRT, and 2,650 (54%) underwent cCRT. Median OS among the sCRT and cCRT groups in patients who were M- was 54.6 versus 39.5 months, respectively (P<.001); differences persisted following propensity score matching (P<.001). In the overall M+ cohort, outcomes for sCRT and cCRT were 36.3 versus 30.5 months (P=.011), but showed equipoise following matching (P=.745). In the R1 and R2 subsets, no differences in OS were seen between cohorts (P=.368 and .553, respectively). When evaluating the sCRT population, there were no OS differences between chemotherapy-first and RT-first after matching (P=.229). Conclusions: Postoperative sCRT was associated with improved survival compared with cCRT in patients with M- disease, with statistical equipoise in those with M+ disease. Differential sequencing of sCRT does not appear to affect survival.