A Study On The Relationship Between Different Radiation Therapy Doses And The Incidence Of Pneumonia After Partial Laryngectomy For Laryngeal Cancer

Purpose: This study investigated the effect of different radiotherapy doses on the incidence of pneumonia after laryngeal cancer surgery,aiming to provide reference for clinicians to choose a reasonable radiotherapy dose to reduce the incidence of pneumonia while taking into account the treatment effect.Methods: Patients diagnosed with laryngeal cancer and treated with surgery and postoperative radiotherapy at the same institution between 2010 and 2020 were retrospectively analyzed.A total of 108 patients were included in this study,and the grouping was based mainly on the magnitude of the radiotherapy dose.Using 50 Gy as the cut-off value,this study was divided into two groups,including the high radiotherapy dose group(radiotherapy dose > 50 Gy)and the low radiotherapy dose group(radiotherapy dose ≤ 50Gy).There were 51 cases in the low radiotherapy dose group;57 cases in the high radiotherapy dose group.Data from this study were collected by an otolaryngologist using the in-hospital BSWHIS electronic medical record system.The primary outcome indicator(pneumonia)in this study was primarily diagnosed and documented by reviewing the imaging data(lung CT)provided by the patients at the time of review.Additional ancillary diagnostic criteria included:(I)body temperature;(II)purulent airway secretions;and(Ⅲ)inflammatory test indicators.If the patient was diagnosed with the presence of pneumonia before radiotherapy,then the pre-and post-imaging data were compared between the two visits,and we also considered the outcome indicators to be positive if there were signs of progressive exacerbation.The swallowing performance score at the last follow-up visit will be used to evaluate the overall clinical outcome of this study(≤1 =normal swallowing;>1 = swallowing dysfunction).In addition,we collected demographic and clinical data characteristics such as age,gender,site of laryngeal cancer,degree of dysphagia,and presence of lymph node metastasis,respectively,and data were collected and imported into statistical software(spss25.0)for data processing to compare the incidence of postoperative pneumonia in the two groups.Results: A total of 108 patients were included in this study,including 103males(95.4%)and 5 females(4.6%).Their mean age at admission was63.61±8.56(range 44-85).The minimum follow-up period was 2 years,with an average of 6.3±3.38(range 2.0-12.8).There were no statistically significant differences in demographic and clinical characteristics between the high and low radiotherapy dose groups,including age,sex,BMI,history of smoking and drinking,and history of previous diseases(hypertension,diabetes mellitus)(p>0.05).Baselines were comparable between groups.In addition,the disease characteristics(location of laryngeal cancer,whether there is lymph node metastasis,tumor size and extent)and treatment characteristics(surgical method,whether concurrent chemotherapy)were not statistically significant in the two groups.The incidence of postoperative pneumonia was 59.3%,and there was a significant difference between the two groups(71.9% in the high-dose group VS 45.1% in the low-dose group),with statistically significant difference(p=0.005).There were 55.6%(60/108)patients with dysphagia(dysphagia score>1)during the follow-up period.The probability of dysphagia in the high-dose group was significantly higher than that in the low-dose group(64.9% VS 45.1%,p=0.039).In addition,9.3%(10/108)of the patients were readmitted due to severe pneumonia,and the proportion of patients who were readmitted due to pneumonia was significantly different between the two groups(15.8% in the high-dose group and 2.0% in the low-dose group,p=0.032).Multivariate logistic regression showed that high-dose radiotherapy was a risk factor for pneumonia(OR=4.224,95%CI =1.603-11.131,p=0.004).Conclusions: In the radiotherapy of laryngeal cancer,the radiation dose >50Gy will increase the incidence of pneumonia.Pneumonia not only affects the quality of life of patients,but also the toxicity and mortality of pneumonia caused by radiotherapy in the long term cannot be ignored.Therefore,we suggest that doctors pay close attention to the lung condition of patients when the radiotherapy dose is more than 50 Gy,evaluate in time,and actively intervene to improve the quality of life of patients.