The application of QCT in the prognostic assessment of mCRC undergoing first-line treatment based on bevacizumab

Bevacizumab induces muscle atrophy by changing the gene expression level of muscle tissue. Quantitative computed tomography (QCT) enables precise measurement of various body compositions, including muscle area. A total of 102 patients with metastatic colorectal cancer (mCRC) undergoing first-line chemotherapy based on bevacizumab were enrolled at thirst Affiliated Hospital of the University of Science and Technology of China. Their body compositions were measured respectively 1 month before and 1 month after the treatment. Treatment-related decline in skeletal muscle index and visceral fat infiltration significantly affect patient prognosis. A predictive model constructed by integrating changes in body composition with patient clinical characteristics effectively predicts the 9-month progression-free survival (PFS) of patients with mCRC. Metastatic colorectal cancer (mCRC), which has spread to other organs (such as the liver or lungs), is commonly treated with a combination of targeted therapy and chemotherapy. Targeted therapy specifically acts on molecular targets on cells, aiming to inhibit or eliminate tumor growth. Bevacizumab is a key targeted drug in both first- and second-line treatments for mCRC (first-line treatment refers to the initial intervention strategy, while second-line treatment is considered when the tumor progresses due to chemotherapy resistance or after the failure of the initial treatment). However, after first-line treatment fails, the duration of tumor non-progression is often shorter than that achieved with first-line treatment. Therefore, distinguishing the differences in first-line treatment efficacy among patients is crucial for developing personalized treatment plans. Previous studies indicate that bevacizumab may cause muscle tissue atrophy. Quantitative Computed Tomography (QCT) can measure various body composition parameters, such as muscle area and visceral fat area. This study, which used QCT to track body composition changes in patients receiving bevacizumab with first-line chemotherapy, found that patients who lost over 6.6% of muscle mass during treatment had poorer outcomes. Thus, changes in body composition can effectively predict treatment efficacy. Currently, the dosage of bevacizumab is based on body surface area (BSA), calculated using height and weight. However, patients with the same BSA may have differing body composition parameters. By accurately measuring body composition changes, QCT could assist clinicians in adjusting bevacizumab dosages or implementing interventions, enabling patients to achieve a more prolonged state of disease stability. The changes in body compositions induced by first-line chemotherapy based on bevacizumab can serve as prognostic indicators for mCRC patients, with the potential to provide auxiliary evidence for personalized dosing selection of bevacizumab in future clinical endeavors.

贝伐珠单抗（Bevacizumab）可通过改变肌肉组织的基因表达水平诱导肌肉萎缩。定量计算机断层扫描（quantitative computed tomography, QCT）可精准测定包括肌肉面积在内的多种身体成分指标。本研究在中国科学技术大学附属第一医院招募了102例接受以贝伐珠单抗为基础的一线化疗的转移性结直肠癌（metastatic colorectal cancer, mCRC）患者，分别于治疗前1个月与治疗后1个月测量其身体成分。治疗相关的骨骼肌指数下降与内脏脂肪浸润显著影响患者预后。整合身体成分变化与患者临床特征构建的预测模型，可有效预测mCRC患者的9个月无进展生存期（progression-free survival, PFS）。转移性结直肠癌（mCRC）已扩散至肝脏、肺部等其他器官，临床通常采用靶向治疗联合化疗的方案进行治疗。靶向治疗可特异性作用于细胞表面的分子靶点，以抑制或清除肿瘤生长。贝伐珠单抗是mCRC一线与二线治疗中的关键靶向药物（一线治疗指初始干预策略，二线治疗则指因化疗耐药导致肿瘤进展或初始治疗失败后采用的治疗方案）。然而，一线治疗失败后，肿瘤无进展时长通常短于一线治疗阶段。因此，区分患者一线治疗疗效的差异对于制定个性化治疗方案至关重要。既往研究提示，贝伐珠单抗可能引发肌肉组织萎缩。定量计算机断层扫描（QCT）可测定多种身体成分参数，如肌肉面积与内脏脂肪面积。本研究通过QCT追踪接受贝伐珠单抗一线化疗患者的身体成分变化，发现治疗期间肌肉量流失超过6.6%的患者预后更差。由此可见，身体成分变化可有效预测治疗疗效。目前贝伐珠单抗的给药剂量基于体表面积（body surface area, BSA）计算，该参数通过身高与体重得出。但体表面积相同的患者，其身体成分参数可能存在差异。通过精准测量身体成分变化，QCT可帮助临床医生调整贝伐珠单抗的给药剂量或实施干预措施，帮助患者实现更持久的疾病稳定状态。接受贝伐珠单抗一线化疗诱导的身体成分变化，可作为mCRC患者的预后指标，有望为未来临床实践中贝伐珠单抗的个性化给药选择提供辅助依据。