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.