Alleviation of dry mouth by saliva substitutes improved swallowing ability and clinical nutritional status of post-radiotherapy head and neck cancer patients: a randomized controlled trial

Abstract

Purpose: The aim of this study is to investigate the effect of an edible saliva substitute, oral moisturizing jelly (OMJ), and a topical saliva gel (GC) on dry mouth, swallowing ability, and nutritional status in post-radiotherapy head and neck cancer patients.

Methods: Sixty-two post-radiation head and neck cancer patients with xerostomia completed a blinded randomized controlled trial. They were advised to swallow OMJ (n = 31) or apply GC orally (n = 31) for 2 months. Outcome measures were assessed at baseline, 1, and 2 months, including subjective and objective dry mouth (Challcombe) scores, subjective swallowing problem scores (EAT-10), water swallowing time, clinical nutritional status (PG-SGA), body weight, and dietary intake.

Results: After 1 and 2 months of interventions, subjective and objective dry mouth scores, subjective swallowing problem scores, swallowing times, and clinical nutritional status in both groups were significantly improved (p < 0.0001). Compared to GC, OMJ group had higher percent improvement in all outcome measures (p < 0.001) except swallowing time and clinical nutritional status. Interestingly, subjective dry mouth scores were significantly correlated with subjective swallowing problem scores (r = 0.5321, p < 0.0001).

Conclusions: Continuous uses of saliva substitutes (OMJ or GC) for at least a month improved signs and symptoms of dry mouth and enhanced swallowing ability. An edible saliva substitute was superior to a topical saliva gel for alleviating dry mouth and swallow problems. These lead to improved clinical nutritional status. Thus, palliation of dry mouth may be critical to support nutrition of post-radiotherapy head and neck cancer patients.

Clinical trial registry: Clinicaltrials.gov NCT03035825.

Keywords: Dysphagia; Head and neck cancer; Nutritional status; Radiation therapy; Saliva substitute; Xerostomia.

Fig. 1

Participants’ flow chart. The diagram depicts the number of recruited volunteer and actual number of participants included in data analysis

Fig. 2

Effect of saliva substitutes on dry mouth. a Changes in subjective dry mouth scores (symptoms) in study group (OMJ; black bar) and control group (GC; gray bar) at baseline, after 1 and 2 months of interventions. Each bar represented mean ± SD of subjective dry mouth scores. (****) indicated p value < 0.0001; repeated measure ANOVA followed by Tukey’s multiple comparison test. b Comparison of changes in subjective dry mouth scores between study group (OMJ) and control group (GC) after 1 and 2 months of interventions. Each bar represented mean ± SD of percent baseline of subjective dry mouth scores. (*) indicated p value < 0.05; unpaired t test. c Changes in objective dry mouth scores (signs) in study group (OMJ; black bar) and control group (GC; gray bar) at baseline, after 1 and 2 months of interventions. Each bar represented mean ± SD of objective dry mouth scores. (*) indicated p value < 0.05; repeated measure ANOVA followed by Tukey’s multiple comparison test. d, e Comparison of changes in objective dry mouth scores between study group (OMJ) and control group (GC) after 1 month (d) or 2 months (e) of interventions. Stacked bar represented percent of participants with better, same or worse outcome, compared to their own baseline values. (***) indicated p value < 0.001, (****) indicated p value < 0.0001; Chi-square test. f Correlation between subjective dry mouth scores and subjective swallow problem scores. Each dot in the dot plot represented co-ordinates of subjective dry mouth scores and subjective swallow problem scores in the same participants. (r = 0.532, p < 0.0001; Pearson correlation analysis)

Fig. 3

Effect of saliva substitutes on swallowing ability. a Changes in subjective swallowing problem scores (symptoms) in study group (OMJ; black bar) and control group (GC; gray bar) at baseline, after 1 and 2 months of interventions. Each bar represented mean ± SD of subjective swallowing problem scores. (****) indicated p value < 0.0001, (*) indicated p value < 0.05; repeated measure ANOVA followed by Tukey’s multiple comparison test. b, C Comparison of changes in subjective swallowing problem scores between study group (OMJ) and control group (GC) after 1 month (b) or 2 months (c) of interventions. Stacked bar represented percent of participants with better (white bar), same/worse (black bar) outcomes, compared to their own baseline values. (*) indicated p value < 0.05, (***) indicated p value < 0.001; Chi-square test. d Changes in swallowing time (objective swallowing ability) in study group (OMJ; black bar) and control group (GC; gray bar) at baseline, after 1 and 2 months of interventions. Each bar represented mean ± SD of swallowing times. (***) indicated p value < 0.001, (****) indicated p value < 0.0001; repeated measure ANOVA followed by Tukey’s multiple comparison test. e, f Comparison of changes in subjective swallowing problem scores between study group (OMJ) and control group (GC) after 1 month (e) or 2 months (f) of interventions. Stacked bar represented percent of participants with better (white bar), same/worse (black bar) outcomes, compared to their own baseline values. The indicated p values were from Chi-square tests

Fig. 4

Effect of saliva substitutes on nutritional status. a Changes in PG-SGA categories of mild, moderate, and severe malnutrition in study group (OMJ; left panel) and control group (GC; right panel) after 1 and 2 months of interventions. Stacked bar represented percent of participants with severe (white bar), moderate (gray bar), and mild (black) malnutrition categories. (*), (**), (****) indicated p value < 0.05, 0.01, and 0.0001; Chi-square tests. b Comparison of changes in PG-SGA scores between study group (OMJ) and control group (GC) after 1 month (left panel) or 2 months (right panel) of interventions. Stacked bar represented percent of participants with better, same, or worse outcome, compared to their own baseline values. The indicated p values were from Chi-square tests. c Changes in energy intakes (% baseline) in study group (OMJ; black bar) and control group (GC; gray bar) at baseline, after 1 and 2 months of interventions. Each bar represented mean ± SD of percent baseline of energy intakes. The indicated p values were from repeated measure ANOVA. d Changes in body weights (% baseline)in study group (OMJ; black bar) and control group (GC; gray bar) at baseline, after 1 and 2 months of interventions. Each bar represented mean ± SD of percent baseline of body weights. The indicated p values were from repeated measure ANOVA