Background The clinicopathologic-radiologic and prognostic characteristics of intratumoral fat in hepatocellular carcinoma (HCC) are critical for personalized treatment but remain understudied. Purpose To investigate the clinicopathologic-radiologic associations and prognostic implications of MRI-assessed intratumoral fat in HCCs. Materials and Methods This retrospective cohort study included consecutive adult patients who underwent resection for solitary HCCs and preoperative contrast-enhanced MRI from two tertiary-care hospitals in East Asia (March 2011 to December 2021) and Western Europe (September 2012 to December 2019). MRI scans were independently evaluated by three radiologists at each hospital. Based on Liver Imaging Reporting and Data System (LI-RADS) version 2018, intratumoral fat was defined as "fat in mass more than adjacent liver," and the homogeneous subtype was defined as intratumoral fat "in absence of mosaic and nodule-in-nodule architecture." Recurrence-free survival (RFS) and overall survival (OS) were estimated using the Kaplan-Meier method and compared using the log-rank test. Cox regression analyses were conducted to identify factors associated with RFS and OS. Results A total of 933 patients were included in the Asian (n = 736; median age, 53 years [IQR, 45-62 years]; 626 male) and European (n = 207; median age, 64 years [IQR, 55-70 years]; 161 male) cohorts. MRI-assessed intratumoral fat was detected in 30% (215 of 726) and 31% (64 of 207) of patients in the Asian and European cohorts, respectively (P = .72). In both cohorts, the steatohepatitic subtype, nonperipheral washout, enhancing capsule, and mosaic architecture were more frequent in tumors with intratumoral fat (P value range, <.001 to .04). Intratumoral fat in general was not associated with RFS or OS in either cohort (P value range, .48-.97). However, in the Asian cohort, homogeneous intratumoral fat was associated with longer RFS (hazard ratio [HR], 0.60; P = .009) and OS (HR, 0.33; P = .008) in multivariable Cox regression analyses. Conclusion MRI-assessed intratumoral fat was more frequent in steatohepatitic HCCs and associated with nonperipheral washout, enhancing capsule, and mosaic architecture. Although intratumoral fat was generally nonprognostic, homogeneous intratumoral fat was associated with longer RFS and OS in the Asian cohort. Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Harmath in this issue.

中文翻译：

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MRI 评估的肝细胞癌瘤内脂肪的预后意义：一项亚洲和欧洲队列研究。


背景 肝细胞癌 （HCC） 瘤内脂肪的临床病理学放射学和预后特征对于个性化治疗至关重要，但仍未得到充分研究。目的 探讨 MRI 评估 HCC 瘤内脂肪的临床病理-放射学关联和预后意义。材料和方法 本回顾性队列研究包括来自东亚（2011 年 3 月至 2021 年 12 月）和西欧（2012 年 9 月至 2019 年 12 月）两家三级医院接受孤立性 HCCs 切除术和术前对比增强 MRI 的连续成年患者。MRI 扫描由每家医院的 3 名放射科医生独立评估。根据肝脏影像学报告和数据系统 （LI-RADS） 2018 版，瘤内脂肪被定义为“脂肪质量超过相邻肝脏”，均质亚型被定义为“在没有马赛克和结节结构”的瘤内脂肪。使用 Kaplan-Meier 方法估计无复发生存期 （RFS） 和总生存期 （OS），并使用对数秩检验进行比较。进行 Cox 回归分析以确定与 RFS 和 OS 相关的因素。结果 共有 933 例患者纳入亚洲 （n = 736;中位年龄，53 岁 [IQR，45-62 岁];626 名男性）和欧洲 （n = 207;中位年龄，64 岁 [IQR，55-70 岁];161 名男性）队列。在亚洲和欧洲队列中，分别在 30% （726 例中的 215 例） 和 31% （207 例中的 64 例） 中检测到 MRI 评估的瘤内脂肪 （P = .72）。在这两个队列中，脂肪肽亚型、非外周洗脱、增强包膜和马赛克结构在瘤内脂肪的肿瘤中更常见 （P 值范围，<.001 至 .04）。 在两个队列中，瘤内脂肪通常与 RFS 或 OS 无关 （P 值范围，.48-.97）。然而，在亚洲队列中，均匀的瘤内脂肪与较长的 RFS 相关（风险比 [HR]，0.60;P = .009） 和 OS （HR， 0.33;P = .008） 进行分析。结论 MRI 评估的瘤内脂肪在脂肪上腺 HCCs 中更常见，并且与非外周洗脱、增强包膜和马赛克结构相关。尽管瘤内脂肪通常没有预后，但在亚洲队列中，均匀的瘤内脂肪与较长的 RFS 和 OS 相关。在 CC BY 4.0 许可证下发布。本文提供了补充材料。另请参阅本期 Harmath 的社论。