Room: AAPM ePoster Library
Purpose: Replanning of Head and Neck cancer (HNC) patients undergoing radiotherapy is prevalent due to anatomical changes during treatment. The threshold of the parameters that identify when to replan are not always clear. This work explores parameters that may influence when a patient has to be replanned.
Methods: The patient cohort examined consisted of 490 HNC patients treated with radiotherapy between 2012 and 2019. 60 Gy, 66 Gy and 70 Gy total prescribed dose each delivered in 2 Gy fractions were identified as the standard fractionation schemes and the patients were grouped accordingly. Weight data were extracted from weekly nutrition appointments and sampled in five fraction increments. Characteristics such as cancer type, adjuvant chemotherapy, and weight loss during radiotherapy were investigated as potential factors influencing replanning. Chemotherapy data were only available for 260 patients treated between 2016 and 2019. Statistics including mean, median and standard deviation were used to compare normalized weight loss trends between groups.
Results: Participants from all groups showed weight loss over the course of treatment, with the 70 Gy cohort decreasing the most on average. It was evident that weight loss could only serve as a predictor for the 66 Gy cohort. Cancer site location was also not predictive of replanning, but it did have some influence on weight loss since patients with oropharyngeal cancer lost more weight than the others. Adjuvant chemotherapy was associated with increased weight loss for all groups but not a higher incidence of replanning except in the 66 Gy patients.
Conclusion: Chemotherapy and site location are associated with weight loss. However, weight loss alone is not a predictor for HNC replanning. Further investigations including an examination of the anatomical changes of the patients during RT are required to predict when a patient has to be replanned.