Abstract: Objective To investigate the value of plasma mSEPT9 detection in the diagnosis and prediction of radiosensitivity of esophageal carcinoma. Methods This study was conducted in 72 patients with esophageal cancer who received radical radiotherapy in the Department of Radiotherapy of First Affiliated Hospital of Bengbu Medical College between January, 2019 and December, 2020. Plasma mSEPT9 of the patients were examined with PCR before and after radiotherapy, with 20 healthy subjects from the physical examination center as the controls. The receiver operating characteristic curve (ROC) was used to assess the value of mSEPT9 in diagnosis of esophageal cancer, and the correlation between mSEPT9 and clinicopathological characteristics of the patients was analyzed. According to their response to radiotherapy, the patients were divided into radiosensitive group and insensitive group, and their plasma mSEPT9 levels were compared before radiotherapy. All the patients were observed for dynamic changes of mSEPT9 levels after radiotherapy to analyze the association of mSEPT9 variation with radiosensitivity of the tumors. Results The sensitivity and specificity of mSEPT9 for the diagnosis of esophageal carcinoma were 62.5% and 100%, respectively, with an area under the ROC curve of 0.813. Plasma mSEPT9 level was correlated with lymph node metastasis and clinical stages of esophageal carcinoma (P<0.05), but not with gender, age, invasion site, tumor length, degree of differentiation, or depth of invasion (P>0.05). The radiosensitive patients had a significantly lower positivity rate for mSEPT9 than the insensitive patients before radiotherapy (53.06% vs 82.61%, P=0.016). In the 72 patients, the positivity rate for mSEPT9 decreased significantly after radiotherapy (30.56% vs 62.5% , P<0.001); the positivity rate was significantly lowered after radiotherapy in the radiosensitive group (14.29% vs 53.06% , P<0.001), but the reduction was not significant in the insensitive group (65.22% vs 82.61%, P=0.125). Conclusion Detection of plasma mSEPT9 level is helpful for diagnosis and prediction of radiosensitivity of esophageal carcinoma.

Key words: mSEPT9; esophageal carcinoma; diagnosis; radiosensitivity