Xerostomia quality of life and resource requirements following parotid sparing adaptive radiotherapy in head and neck cancers: Results of a prospective cohort study (Study ID CTRI/2017/11/010683).

Background And Purpose: Parotid sparing adaptive radiotherapy (PSART) is resource intensive to implement. Selection criteria for using ART and its impact on quality of life (QoL) is poorly reported. This has been addressed in our study.

Materials And Methods: Patients planned for curative radiotherapy for Head Neck Cancers were recruited following informed consent in a prospective cohort study. PSART was planned if the mean dose to index parotid(s) increased by 2% from the baseline approved plan. To assess the resource requirements of PSART manpower and time required for treatment planning both for initial as well as PSART was documented. Patient reported QoL using QualiXeQLS and EORTC QLQ C30 and HN35 were obtained pre radiotherapy, and at 3 and 9 months post radiotherapy.

Results: Of the ninety patients accrued, 87 were evaluable. 45 (51%) received PSART based on the prespecified criteria. The average time spent in contouring (276 min versus 133 min) and treatment planning (293 min versus 108 min) were almost doubled when PSART was implemented. XeQoL scores at 3 months were significantly worse in those receiving PSART (mean 2.3 vs 1.2, p 0.002). Despite this, xerostomia related QoL recovered to near baseline scores by 9 months after receiving PSART.

Conclusion: Implementation of PSART is resource intensive. The proposed cutoff for implementing PSART identifies a higher risk population that have worse xerostomia related quality of life. This study lays the foundation for a randomized trial to determine the efficacy of PSART on xerostomia related QoL.