Effect of bilateral superficial parotid gland sparing IMRT on xerostomia and QOL: A prospective study.

Background: Superficial lobe constitutes 80% of the parotid and is situated lateral to mandible and can be better spared during intensity modulated radiation therapy (IMRT) for head and neck cancer (HNC). This study aimed to see the impact of bilateral superficial parotid gland (PG) sparing IMRT on xerostomia and quality of life (QOL) in patients with HNC receiving radiation.

Study design: Prospective, questionnaire-based study.

Materials and methods: Thirty-four patients with histopathologically proven non-nasopharyngeal non-oral cavity HNC were included in this study. IMRT technique was used and a constraint of 24 Gy was given to combined superficial PG. Physician- and patient-rated xerostomia and QOL scores were recorded at baseline and two weeks, three months, and six months post-radiation therapy (RT). The combined superficial PG dose correlated with xerostomia and QOL scores.

Results: The combined superficial PG and combined whole PG mean dose was 18.71 Gy and 30 Gy, respectively, and the difference was statistically significant (P-< 0.001). At two weeks, three months, and six months post-RT, the odds of xerostomia scores were 0.11, 0.071, 0.042, respectively for a median dose of <18 Gy compared to >18 Gy and was statistically significant P=(0.001).

Conclusion: Bilateral superficial PG sparing IMRT is beneficial in reducing xerostomia and translates to a better QOL.