The impact of head and neck radiotherapy on salivary flow and quality of life: Results of the ORARAD study

Abstract

Objectives: Salivary hypofunction and xerostomia, are common side effects of radiotherapy, negatively impacting quality of life. The OraRad study presents results on the longitudinal impact of radiotherapy on salivary flow and patient-reported outcomes.

Patients and methods: Prospective, multicenter cohort study of 572 patients receiving curative-intent head and neck radiotherapy (RT). Stimulated salivary flow (SSF) rate and patient-reported outcomes were measured prior to RT and at 6- and 18-months post-RT. Linear mixed effects models examined the relationship between RT dose and change in salivary flow, and change in patient-reported outcomes.

Results: 544 patients had baseline salivary flow measurement, with median (IQR) stimulated flow rate of 0.975 (0.648, 1.417) g/min. Average RT dose to parotid glands was associated with change in salivary flow post-RT (p < 0.001). Diminished flow to 37% of pre-RT level was observed at 6 months (median: 0.358, IQR: 0.188 to 0.640 g/min, n = 481) with partial recovery to 59% of pre-RT at 18 months (median: 0.575, IQR: 0.338 to 0.884 g/min, n = 422). Significant improvement in patient-reported swallowing, senses (taste and smell), mouth opening, dry mouth, and sticky saliva (p-values < 0.03) were observed between 6 and 18 months post-RT. Changes in swallowing, mouth opening, dry mouth, and sticky saliva were significantly associated with changes in salivary flow from baseline (p-values < 0.04).

Conclusion: Salivary flow and patient-reported outcomes decreased as a result of RT, but demonstrated partial recovery during follow-up. Continued efforts are needed to improve post-RT salivary function to support quality of life.

Keywords: Head and Neck Neoplasms; Quality of Life; Radiotherapy; Xerostomia.

Conflict of interest statement

Conflicts of Interest: None declared

Copyright © 2022 Elsevier Ltd. All rights reserved.

Figures

Figure 1:

Distribution of salivary flow at baseline (n=544), 6 months post-RT (n=481), and 18 months post-RT (n=422). The dot and line represent mean ± SD at each visit.

Figure 2:

Loess curve for salivary flow rate (g/min) by primary site of RT (N=564)

Figure 3:

Loess curve for salivary flow rate (g/min) by quartiles of average RT dose to the parotid glands (N=563). Dose to the parotids is categorized based on quartiles: quartile 1≤;2018 (cGy), quartile 2>2018 and ≤2586 (cGy), quartile 3 >2586 and ≤ 3358 (cGy), and quartile 4 > 3358(cGy). Visit month has been jittered for visualization purposes. Statistical comparisons between quartiles are provided in Supplementary Table S4.

Figure 4

(a-e): Selected EORTC QLQ-H&N35 scales at baseline, 6 months post-RT, and 18 months post-RT for a) swallowing b) senses problems c) opening mouth and d) dry mouth, and e) sticky saliva. A score ≥ 50 corresponds to responses of “quite a bit” or “very much” for the opening mouth, dry mouth, and sticky saliva scale.