The objective of this study was to describe the patterns of failure (POF), frequency of low volume relapse (LVR), and candidacy for further ablative therapy at time of disease progression (PD) after chemoradiation and consolidative immunotherapy (CRT+ICI) in patients with stage III non-small cell lung cancer (NSCLC).
We identified 229 consecutive patients with stage III NSCLC treated with CRT+ICI between October 2017 and December 2021 at a single institution. PD was classified as isolated locoregional failure (LRF), isolated distant failure (DF), or synchronous LRF+DF. Any LRF was subclassified as in-field failure (IFF), marginal failure (MF), or out-of-field failure (OOF). LVR was considered ≤3 sites of PD in any number of organs. Ablative candidates were defined as having ≤5 sites of PD radiographically amenable to high-dose radiation or surgery. Time-to-event data were calculated via cumulative incidence and Kaplan Meier methods. Multivariable Cox modeling was used to correlate characteristics of relapse with post-progression survival (PPS).
Overall, 119/229 (52%) patients had PD; 20/119 (21%) patients had isolated LRF, 28/119 (24%) had synchronous LRF+DF, and 71/119 (60%) patients had isolated DF. Of patients with any LRF, 28/48 (58%) had IFF, 10/48 (21%) had MF, and 10/48 (21%) had OOF. The cumulative incidence of LRF and DF was 13% (95%CI 9.2-18) and 32% (95%CI 26-38) at 1-year and 19% (95%CI 14-24) and 39% (95%CI 33-46) at 2-years, respectively. Overall, 64 (54%) patients were considered to have LVR. At time of PD, 60 (50%) patients were eligible for ablative therapy. Patients with LVR had longer median survival versus with high volume relapse (37.4 vs 15.2 months, p<0.001). On multivariable analysis, LVR (HR 0.32, 95% CI 0.18-0.56, p<0.001) was associated with improved PPS.
After CRT+ICI, approximately half of patients experience LVR at time of PD and are candidates for ablative therapies. Prospective trials are needed to validate the optimal treatment strategy of LVR.
Copyright © 2023. Published by Elsevier Inc.
