Factors affecting laryngeal cancer relapse after postoperative radiotherapy and relationship between relapse with radiotherapy dose / 中国医学物理学杂志

ABSTRACT

Objective To explore the factors associated with laryngeal cancer relapse after postoperative radiotherapy,discuss the relationship between radiotherapy dose under various surgical procedures and relapse,and analyze their effects on survival rate.Methods The clinical data of 134 patients with laryngeal cancer treated with postoperative radiotherapy in Shijiazhuang People's Hospital were retrospectively analyzed.The risk factors of postoperative relapse were analyzed with univariate analysis,followed by multivariate Logistic regression analysis.The relationships between radiotherapy doses under various surgical procedures and the relapse were discussed.Kaplan-meler method and Log rank test were used to analyze the 2-year survival rate of laryngeal cancer patients.Results Thirty out of the 134 patients relapsed after treatment,and there was no recurrence in the remaining 104 patients.Multivariate Logistic regression analysis identified clinical stage(Ⅲ-Ⅳ),T stage(T3-T4),N stage(N1-N3),radiotherapy dose(low-dose),thyroid cartilage invasion(yes)and surgical margin(positive)as independent risk factors for postoperative laryngeal cancer relapse(OR>1,P<0.05).The relapse rates of patients receiving high-dose radiotherapy after laser vocal cord mass resection/partial laryngectomy and total laryngectomy under self-retaining laryngoscope were lower than those of patients receiving low-dose radiotherapy,with a statistically significant difference in overall relapse rate(P<0.05).As of June 2023,the median follow-up time of 134 patients undergoing postoperative radiotherapy for laryngeal cancer was 14.23 months(1-24 months),and there were 8 deaths in low-dose group and 2 deaths in high-dose group.The estimated median survival times in low-and high-dose groups were 19.13 months and 22.13 months.The survival curves in two groups were different(Log rank P=0.20),with high-dose group outperforming low-dose group.Conclusion The overall therapeutic effect of surgery combined with postoperative radiotherapy for laryngeal cancer is favorable.However,clinical stage,T stage,N stage,low-dose radiotherapy,tumor invasion into thyroid cartilage,positive surgical margin,and>11 weeks from postoperation to radiotherapy completion were risk factors for disease relapse.In clinical practice,the radiotherapy dose should be appropriately increased based on the patient's condition to improve prognosis and extend survival duration.