Xerostomia: an immunotherapy-related adverse effect in cancer patients.

Purpose: Xerostomia is an underrecognized adverse effect of immunotherapy (IO) that can significantly impact patients' quality of life by leading to poor nutritional status, dental caries, and oral candidiasis. The purpose of this case series was to describe the onset, severity, clinical course, and management of IO-induced xerostomia.

Methods: This was a retrospective case series conducted at an outpatient cancer center. Data collection was conducted via chart review. The severity of dry mouth symptoms was graded using the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.

Results: Six patients with advanced solid tumors who received a PD-1 inhibitor or PD-1/CTLA-4 inhibitor combination therapy were evaluated. The median time to onset of xerostomia was 4.5 months overall, though symptoms developed sooner in patients who received IO as subsequent-line therapy (median = 1.9 months). All patients developed other immune-related adverse events (IRAEs) such as hypothyroidism. Five patients (83%) had grade 2 dry mouth symptoms, and similarly, 5 patients eventually required prescription medications such as sialogogues and topical or systemic corticosteroids to alleviate symptoms. Two patients (33%) required interruptions in IO. All 3 patients who received cevimeline noticed improvement in symptoms, and one patient who received prednisone dosed at 1 mg/kg/day tapered over 5 weeks also experienced significant relief.

Conclusion: While the optimal management of IO-induced xerostomia has not yet been established by national guidelines, increased awareness can prompt faster initiation of supportive care measures that can prevent significant discomfort and poor oral intake. Thoughtful use of over-the-counter topical agents, sialogogues, corticosteroids, and treatment interruptions can help improve tolerability of this adverse effect.