Objective: To observe the effect of adaptive replanning on adverse reactions and clinical outcome of nasopharyngeal carcinoma treated by helical tomotherapy.
Methods: Fifty nasopharyngeal carcinoma patients treated by TomoTherapy system were retrospectively analyzed. Among these patients, 25 received repetitive CT simulation and replanning, and another 25 case-matched control patients without replanning were identified by matching age, gender, pathological type, UICC stage, weight loss, etc. Wilcoxon test was used to evaluate the effect of replanning on acute and chronic radiation reactions within individuals. Kaplan-Meier study was used to estimate the survival of patients with or without replanning.
Results: There was a significant difference in late salivary grand damage between the replanning and the control group (P=0.046), while no difference was observed in acute or other late side effects between the two groups. The median follow-up of the two groups was 32 months (7-42 months) and 26 months (8-46 months), respectively. The median local relapse-free survival time, 2-year local relapse-free survival and 2-year lymphnode relapse-free survival in the two groups were similar (36 months, 92% and 100%). No significant difference was found in the 2-year metastasis relapsefree survival (80% and 96%) and the 2-year overall survival between the two groups (88% and 92%, P>0.05).
Conclusion: Adaptive replanning may reduce the severity of late damage of salivary glands after helical tomotherapy in nasopharyngeal carcinoma patients without improvement of 2-year survival rate.