Purpose

Prognostic significance of volumetric ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computer tomography (PET/CT) parameters in carbon-ion radiotherapy (C-ion RT) treated stage I non-small cell lung cancer, and need of histology-wise separate cut-off values for risk stratification were assessed.

Methods

Thirty-nine patients (29 men and 10 women, 71.9 ± 8.3 years) who underwent FDG PET/CT examinations before C-ion RT were retrospectively evaluated. FDG-PET parameters: standardized uptake values (SUVmax, SUVpeak, and SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG), and clinicopathological variables were assessed for prognosis using Cox proportional hazards regression analysis. Mann-Whitney test compared medians of significant parameters between adenocarcinoma (AC) and squamous cell carcinoma (SCC), and Kaplan-Meier curves were plotted for median-based low- and high-risk groups.

Results

Median follow-up period was 44.8 months. 1/2/3-year overall survival (OS), progression-free survival (PFS) and local control (LC) rates were 94.9/84.3/70.8, 82.1/69.2/58.4 and 97.3/85.7/82.3%. Multivariate analysis revealed age (hazard ratio, HR: 1.09; 95% confidence interval, CI: 1.0–1.19, p < 0.05) and MTV (HR 4.83, 95% CI 1.21–19.27, p < 0.03) predicted OS, and only MTV predicted PFS (HR 5.3, CI 1.32–21.35, p < 0.02) independently. Compared with AC, SCC had higher MTV (median, 6.625cm³ vs 0.2 cm³, p < 0.01). Single MTV cut-off based on overall cohort was insignificant in SCC for PFS (p > 0.02); separate cut-offs of MTV, 0.2 cm³ for AC (p < 0.03) and 6.625 cm³ for SCC (p < 0.05) were relevant.

Conclusion

Among all FDG PET/CT parameters, only MTV beared prognostic ability for stage I NSCLC treated with C-ion RT, and its histological variation may need consideration for risk-adapted therapeutic management.

中文翻译：

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半定量FDG-PET参数在碳离子放射治疗I期非小细胞肺癌中的预后意义

目的

体积¹⁸ F-氟脱氧葡萄糖（FDG）正电子发射断层扫描/计算机断层扫描（PET / CT）参数在碳离子放射治疗（C-ion RT）治疗的I期非小细胞肺癌中的预后意义，并且需要进行组织学检查评估了风险分层的单独的临界值。

方法

回顾性评估了在C离子RT前接受FDG PET / CT检查的39例患者（29例男性和10例女性，71.9±8.3岁）。FDG-PET参数：使用Cox比例风险回归分析评估标准化摄取值（SUVmax，SUVpeak和SUVmean），代谢肿瘤体积（MTV）和总病变糖酵解（TLG）以及临床病理学变量以评估预后。Mann-Whitney测试比较了腺癌（AC）和鳞状细胞癌（SCC）之间重要参数的中位数，并绘制了中位数低危和高危人群的Kaplan-Meier曲线。

结果

中位随访期为44.8个月。1/2/3年总生存率（OS），无进展生存率（PFS）和局部控制（LC）率为94.9 / 84.3 / 70.8、82.1 / 69.2 / 58.4和97.3 / 85.7 / 82.3％。多因素分析显示年龄（危险比，HR：1.09； 95％置信区间，CI：1.0-1.19，p <0.05）和MTV（HR 4.83，95％CI 1.21-19.27，p <0.03）可预测OS，仅MTV独立预测PFS（HR 5.3，CI 1.32–21.35，p <0.02）。与AC相比，SCC的MTV更高（中位数为6.625cm ³ vs 0.2 cm ³，p <0.01）。对于PFS，SCC中基于总体队列的单个MTV临界值无统计学意义（p > 0.02）；MTV的单独临界值，0.2 cm ³AC（p <0.03）和SCC 6.625 cm ³（p <0.05）是相关的。

结论

在所有的FDG PET / CT参数中，只有MTV能够接受C离子RT治疗的I期NSCLC的预后能力，并且其组织学变化可能需要考虑风险适应性的治疗管理。