Abstract
PURPOSE: The aim of this study was to investigate a first-site-metastasis pattern (FSMP) in unresectable stage III NSCLC after concurrent chemoradiotherapy (cCRT) with or without immune checkpoint inhibition (ICI). METHODS: We defined three patient subgroups according to the year of initial multimodal treatment: A (2011-2014), B (2015-2017) and C (2018-2020). Different treatment-related parameters were analyzed. Observed outcome parameters were brain metastasis-free survival (BMFS), extracranial distant metastasis-free survival (ecDMFS) and distant metastasis-free survival (DMFS). RESULTS: 136 patients treated between 2011 and 2020 were included with ≥ 60.0 Gy total dose and concurrent chemotherapy (cCRT); thirty-six (26%) received ICI. Median follow-up was 49.7 (range:0.7-126.1), median OS 31.2 (95% CI:16.4-30.3) months (23.4 for non-ICI vs not reached for ICI patients, p = 0.001). Median BMFS/ecDMFS/DMFS in subgroups A, B and C was 14.9/16.3/14.7 months, 20.6/12.9/12.7 months and not reached (NR)/NR/36.4 months (p = 0.004/0.001/0.016). For cCRT+ICI median BMFS was 53.1 vs. 19.1 months for cCRT alone (p = 0.005). Median ecDMFS achieved 55.2 vs. 17.9 (p = 0.003) and median DMFS 29.5 (95% CI: 1.4-57.6) vs 14.93 (95% CI:10.8-19.0) months (p = 0.031), respectively. Multivariate analysis showed that age over 65 (HR:1.629; p = 0.036), GTV ≥ 78 cc (HR: 2.100; p = 0.002) and V20 ≥ 30 (HR: 2.400; p = 0.002) were negative prognosticators for BMFS and GTV ≥ 78 cc for ecDMFS (HR: 1.739; p = 0.027). After onset of brain metastasis (BM), patients survived 13.3 (95% CI: 6.4-20.2) months and 8.6 months (95% CI: 1.6-15.5) after extracranial-distant-metastasis (ecDM). Patients with ecDM as FSMP reached significantly worse overall survival of 22.1 (range:14.4-29.8) vs. 40.1 (range:18.7-61.3) months (p = 0.034) in the rest of cohort. In contrast, BM as FSMP had no impact on OS. CONCLUSION: This retrospective analysis of inoperable stage III NSCLC patients revealed that age over 65, V20 ≥ 30 and GTV ≥ 78 cc were prognosticators for BMFS and GTV ≥ 78 cc for ecDMFS. ICI treatment led to a significant improvement of BMFS, ecDMFS and DMFS. ecDM as FSMP was associated with significant deterioration of OS, whereas BM as FSMP was not.