BACKGROUND The PET-derived metabolic tumor volume (MTV) is an independent prognosticator in non-small cell lung cancer (NSCLC) patients. We analyzed the prognostic value of residual MTV (rMTV) after completion of chemoradiotherapy (CRT) in inoperable stage III NSCLC patients with and without immune checkpoint inhibition (ICI). METHODS Fifty-six inoperable stage III NSCLC patients (16 female, median 65.0 years) underwent 18F-FDG PET/CT after completion of standard CRT. rMTV was delineated on 18F-FDG PET/CT using a standard threshold (liver SUVmean + 2 × standard deviation). 21/56 patients underwent additional ICI (CRT-IO, 21/56 patients) thereafter. Patients were divided in volumetric subgroups using median split dichotomization (MTV ≤ 4.3 ml vs. > 4.3 ml). rMTV, clinical features, and ICI-application were correlated with clinical outcome parameters (progression-free survival (PFS), local PFS (LPFS), and overall survival (OS). RESULTS Overall, median follow-up was 52.0 months. Smaller rMTV was associated with longer median PFS (29.3 vs. 10.5 months, p = 0.015), LPFS (49.9 vs. 13.5 months, p = 0.001), and OS (63.0 vs. 23.0 months, p = 0.003). CRT-IO patients compared to CRT patients showed significantly longer median PFS (29.3 vs. 11.2 months, p = 0.034), LPFS (median not reached vs. 14.0 months, p = 0.016), and OS (median not reached vs. 25.2 months, p = 0.007). In the CRT subgroup, smaller rMTV was associated with longer median PFS (33.5 vs. 8.6 months, p = 0.001), LPFS (49.9 vs. 10.1 months, p = 0.001), and OS (63.0 vs. 16.3 months, p = 0.004). In the CRT-IO subgroup, neither PFS, LPFS, nor OS were associated with MTV (p > 0.05 each). The findings were confirmed in subsequent multivariate analyses. CONCLUSION In stage III NSCLC, smaller rMTV is highly associated with superior clinical outcome, especially in patients undergoing CRT without ICI. Patients with CRT-IO show significantly improved outcome compared to CRT patients. Of note, clinical outcome in CRT-IO patients is independent of residual MTV. Hence, even patients with large rMTV might profit from ICI despite extensive tumor load.

中文翻译：

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残留代谢肿瘤体积在放化疗后不能手术的 III 期 NSCLC 中的不同作用±免疫检查点抑制。

背景 PET 衍生的代谢性肿瘤体积 (MTV) 是非小细胞肺癌 (NSCLC) 患者的独立预后指标。我们分析了在有和没有免疫检查点抑制 (ICI) 的不可手术 III 期 NSCLC 患者中，完成放化疗 (CRT) 后残留 MTV (rMTV) 的预后价值。方法 56 名不能手术的 III 期 NSCLC 患者（16 名女性，中位年龄 65.0 岁）在完成标准 CRT 后接受了 18F-FDG PET/CT。使用标准阈值（肝脏 SUVmean + 2 × 标准差）在 18F-FDG PET/CT 上描绘 rMTV。此后，21/56 名患者接受了额外的 ICI（CRT-IO，21/56 名患者）。使用中位数分割二分法（MTV ≤ 4.3 ml vs. > 4.3 ml）将患者分为体积亚组。rMTV，临床特征，OS 也与 MTV 无关（每个 p > 0.05）。这些发现在随后的多变量分析中得到证实。结论 在 III 期 NSCLC 中，较小的 rMTV 与优异的临床结果高度相关，尤其是在没有 ICI 的情况下接受 CRT 的患者。与 CRT 患者相比，CRT-IO 患者的结果显着改善。值得注意的是，CRT-IO 患者的临床结果与残留 MTV 无关。因此，即使肿瘤负荷较大，即使是 rMTV 较大的患者也可能从 ICI 中获益。CRT-IO 患者的临床结果与残留 MTV 无关。因此，即使肿瘤负荷较大，即使是 rMTV 较大的患者也可能从 ICI 中获益。CRT-IO 患者的临床结果与残留 MTV 无关。因此，即使肿瘤负荷较大，即使是 rMTV 较大的患者也可能从 ICI 中获益。