Sparing Parotid Ducts Via MRI Sialography for Reduced Patient-Reported Xerostomia

Radiation-induced dry mouth (xerostomia) is the most commonly reported long-term side effect in patients receiving radiation therapy (RT) for head and neck cancer. It occurs when saliva production decreases and the saliva becomes thicker. Patients with xerostomia often have trouble chewing, swallowing, and speaking, and are more likely to develop tooth decay. These problems can significantly lower a patient's quality of life-and the impact tends to get worse over time.

The most common way to reduce radiation-related dry mouth is by limiting the average radiation dose to the parotid glands (which produce saliva). However, this is often not possible because of the patient's anatomy, and many patients still report moderate to severe symptoms long after treatment.

To reduce side effects, some studies have tested giving a lower radiation dose (60Gy instead of the usual 70Gy) in patients with low-risk, HPV-associated tumors. While this has helped improve overall symptoms, xerostomia still remains the most severe and persistent problem reported by patients.

New strategies are needed to better protect patients from radiation-related dry mouth and help maintain their quality of life after treatment. Recent research shows that the parotid gland does not respond evenly to radiation; certain areas, especially large salivary ducts where stem/progenitor cells live, may be key for recovery after damage. If these ducts can be located during treatment planning, the radiation dose to them could be reduced.

A pilot study showed that using MRI sialography to identify the parotid ducts and plan radiation therapy around them is both possible and promising. Patients who received this type of duct-sparing RT had fewer moderate-to-severe dry mouth symptoms compared to patients treated with standard RT (46% vs. 71% at 6 months, and 36% vs. 50% at 12 months post-treatment).

A larger, randomized study is still needed to confirm whether reducing radiation dose to the parotid ducts can meaningfully lower the risk of xerostomia and improve recovery after radiation treatment.

Inclusion criteria

To participate in this study a subject must meet all of the eligibility criteria outlined below. Eligibility must be maintained for the subject to be considered eligible for ongoing trial participation.

• Provide written informed consent to participate in the study and HIPAA authorization for release of personal health information.
• Able to comply with study procedures based on the judgment of the clinical investigator.
• Male or female, aged ≥ 18 years at the time of consent.
• Eastern Cooperative Oncology Group performance status 0-2 at the time of consent.
• Women of reproductive potential must use highly effective contraception.
• T0-4, N0-3, M0 stage cancer of the oropharynx (American Joint Committee on Cancer Staging System 8th edition) planned for definitive radiotherapy +/- chemotherapy.
• No contraindications for magnetic resonance imaging (MRI).

Exclusion criteria

An individual who meets any of the following criteria will be excluded from participation

In this study:

• Patients with Sjogren's disease or baseline xerostomia.
• Patients with lesions involving the salivary glands on diagnostic imaging
• Patients with an allergy to lemon juice
• Prior lifetime history of radiation therapy to the head and neck
• Current pregnancy or lactation.