Menichelli Claudia, Casamassima Franco, Aristei Cynthia, Ingrosso Gianluca, Borghesi Simona, Arcidiacono Fabio, Lancellotta Valentina, Franzese Ciro, Arcangeli Stefano
Ecomedica Radiotherapy, Empoli, Italy.
Radiation Oncology Section, University of Perugia and Perugia General Hospital, Italy.
Rep Pract Oncol Radiother. 2022 Mar 22;27(1):32-39. doi: 10.5603/RPOR.a2021.0130. eCollection 2022.
The liver is the first metastatic site in 15-25% of colorectal cancer patients and one of the first metastatic sites for lung and breast cancer patients. A computed tomography (CT ) scan with contrast medium is a standard procedure for assessing liver lesions but magnetic resonance imaging (MRI) characterizes small lesions better thanks to its high soft-tissue contrast. Positron emission tomography with computed tomography (PET-CT ) plays a complementary role in the diagnosis of liver metastases. Triphasic (arterial, venous and time-delayed) acquisition of contrast-medium CT images is the first step in treatment planning. Since the liver exhibits a relatively wide mobility due to respiratory movements and bowel filling, appropriate techniques are needed for target identification and motion management. Contouring requires precise recognition of target lesion edges. Information from contrast MRI and/or PET-CT is crucial as they best visualize metastatic disease in the parenchyma. Even though different fractionation schedules were reported, doses and fractionation schedules for liver stereotactic radiotherapy (SRT ) have not yet been established. The best local control rates were obtained with BED values over 100 Gy. Local control rates from most retrospective studies, which were limited by short follow-ups and included different primary tumors with intrinsic heterogeneity, ranged from 60% to 90% at 1 and 2 years. The most common SRT-related toxicities are increases in liver enzymes, hyperbilirubinemia and hypoalbuminemia. Overall, late toxicity is mild even in long-term follow-ups.
在15%-25%的结直肠癌患者中，肝脏是首个转移部位，也是肺癌和乳腺癌患者的首个转移部位之一。增强计算机断层扫描（CT）是评估肝脏病变的标准程序，但磁共振成像（MRI）因其高软组织对比度，对小病变的特征显示更佳。正电子发射断层扫描联合计算机断层扫描（PET-CT）在肝转移瘤的诊断中起辅助作用。增强CT图像的三相（动脉期、静脉期和延迟期）采集是治疗计划的第一步。由于肝脏因呼吸运动和肠腔充盈而具有相对较大的移动性，因此需要适当的技术来进行靶区识别和运动管理。靶区勾画需要精确识别靶病变边缘。对比增强MRI和/或PET-CT的信息至关重要，因为它们能最佳地显示实质内的转移病灶。尽管有不同的分割方案报道，但肝脏立体定向放射治疗（SRT）的剂量和分割方案尚未确定。生物等效剂量（BED）值超过100 Gy时可获得最佳的局部控制率。大多数回顾性研究的局部控制率在1年和2年时为60%至90%，这些研究受随访时间短的限制，且纳入了具有内在异质性的不同原发性肿瘤。最常见的与SRT相关的毒性反应是肝酶升高、高胆红素血症和低白蛋白血症。总体而言，即使在长期随访中，晚期毒性也较轻。
