The Effectiveness of 3% Citric Acid versus Sodium Bicarbonate (Baking Soda) Mouthwash for the Prevention of Radiation-Induced Xerostomia Among Patients Receiving Conventional Radiation Therapy for Head and Neck Malignancies

Abstract

Purpose/Objectives
Majority of head and neck malignancies require Radiation Therapy (RT). Conventional radiotherapy produces toxicities such as xerostomia, which leads to multiple complications if left untreated. In this study, we determined the effectiveness of using 3% citric acid versus NaHCO3 (baking soda) mouthwash in the prevention of xerostomia for patients undergoing conventional radiation therapy to the head and neck malignancies.

Materials/Methods
32 patients with head and neck malignancies were randomized to two groups (16 per group). The first group received 3% citric acid mouthwash whereas the 2nd group received sodium bicarbonate mouthwash. Salivary flow rate and RTOG Scoring for xerostomia were collected.

Results
Salivary flow rates were comparable at baseline but decreased steadily as treatment progressed. A significant difference in flow rates were observed (P=.010) on the 5th day which coincided with the incidence of xerostomia, wherein the proportion in the control arm was more than double of that in the experimental arm (69% vs. 31%). Also, majority in the citric acid group (75%) reported RTOG score of 0, while most in the control group (69%) had an RTOG score of 1 (P=.013). On the 10th day, all participants had varying degrees of mouth dryness. Mild xerostomia was more frequently noted in the citric acid group on day 15 (94% vs. 56%, P=.037). On the 20th day, 75% in the experimental arm had mild xerostomia, while most in the control arm (81%) had moderate signs and symptoms of mouth dryness (P=.001). From day 25 onwards, moderate xerostomia in the experimental and control groups were 81% and 94%, respectively. The average dose on either parotid gland is > 40 Gy. Profiles of mouth dryness were significantly better in the citric acid arm on days 5, 15, and 20.

Conclusion
The comparison of the experimental versus control group demonstrated the citric acid’s higher effectiveness as a sialagogue as evidenced by higher salivary flow rate, delayed onset, delayed progression and milder symptomatology. However, its effectiveness is dependent on the functionality of the viable salivary glands.