Clinical application of MR-guided radiotherapy based on MR-linac in esophageal cancer patients / 国际肿瘤学杂志

ABSTRACT

Objective:To explore the application process, efficacy and safety of MR-guided radiotherapy based on MR-linac in esophageal cancer.Methods:The clinical data of patients with esophageal cancer treated with MR-linac at Shandong Cancer Hospital and Institute from September 2021 to July 2022 were retrospectively analyzed, to investigate the treatment process of esophageal cancer with MR-linac, and to analyze the efficacy and safety of patients. All patients received MR-guided radiotherapy, underwent CT and MR localization, target area delineation, and design of the Monaco treatment planning system plan. Adaptation-to-position adjustment was conducted during the pre-treatment evaluation. The median number of fractions was 25, the median single dose of planning target volume was 1.8 Gy, and the median total dose was 50.2 Gy. Median follow-up was 16 months.Results:Among the 12 patients in the whole group, there were 1 case of cervical esophageal cancer, 3 cases of upper thoracic esophageal cancer, 4 cases of middle thoracic esophageal cancer and 4 cases of lower thoracic esophageal cancer, including 3 cases of neoadjuvant radiotherapy and 9 cases of radical radiotherapy. All patients had a smooth treatment process. The median treatment time was 33 min, and the patients had good compliance. For patients with radical radiotherapy, one month after radiotherapy, the number of objective remission cases was 3, and the number of disease-control cases was 9; six months after radiotherapy, the number of objective remission cases was 3, and the number of disease-control cases was 6. All patients treated with neoadjuvant radiotherapy underwent surgery within 2 months, and one patient achieved pathological complete remission. The most common acute adverse reactions were radiation esophagitis (7 cases) and leukopenia in bone marrow suppression (8 cases), with late-stage adverse reactions being radiation pneumonia (1 case). The adverse reactions to radiotherapy were slight, and no grade 4 or above adverse reactions were observed.Conclusion:The clinical treatment process for esophageal cancer under MR-guided radiotherapy based on MR-linac is feasible, with good curative effects and mild adverse reactions.