Study of dosimetry and clinical factors for assessment of xerostomia in head and neck squamous cell carcinoma treated by intensity-modulated radiotherapy: A prospective study.

AIM: Clinical and dosimetric factors related to toxicity in terms of xerostomia in patients with head and neck squamous cell cancer (HNSCC) treated with intensity-modulated radiotherapy (IMRT).

MATERIALS AND METHODS: Patients older than 18 years, with the WHO Performance Status Score <2 with primary diagnosis of HNSCC Stage II, III, and IV who had undergone primary or postoperative radiotherapy (RT) treated by IMRT at the center, from November 2015 to November 2016 were included in the study. Patients were assessed by physical examination and questioned to score their quality of life for dryness (HNDR) and stickiness (HNSS) by EORTC-HN-35 (Hindi or English version) at baseline (before treatment), at 3, 6, and 12 months following treatment. The validation of EORTC-HN-35 for HNDR and HNSS in patients was handed.

RESULTS: Thirty patients were included in the study. The mean symptom score values for HNSS at baseline, 3, 6, and 12 months' post-RT treatment were 17.8, 62.2, 64.4, and 20.8, respectively. Dryness and stickiness also increased over 3-6 months in follow-up but slightly relieved at 12 months, but it could not reach to baseline. In subgroup analysis, at baseline mean score of dryness of mouth in elderly patients (≥60 years) ( P = 0.248), poor performance status (Eastern Cooperative Oncology Group 2) ( P = 0.80) and patients with advanced stage (Stage III and IVA) ( P = 0.185) was higher. Correlation of normal tissue complication probability for xerostomia with contralateral mean parotid gland showed insignificant linearity with shallow curve.

CONCLUSION: Patients remained symptomatic for xerostomia chiefly till 6 months' postirradiation, but it was slightly relieved in 12 months but could not reach the baseline. Dosimetric sparing ofcontralateral parotid resulted in decreased probability of developing xerostomia.