High-Dose Oral Vitamin D for Toxic Effects of the Skin Associated With Chemotherapy and Radiation.

Abstract

Importance: Severe cutaneous toxic effects from chemotherapy and radiation often require treatment interruptions. High-dose oral vitamin D (hdVD) has shown potential as a rapid immunomodulator in experimental models and small human studies, but robust clinical data in oncology populations remain limited.

Objective: To evaluate the clinical response, safety profile, and time to improvement for hdVD in patients with toxic erythema of chemotherapy (TEC) and acute radiation dermatitis (ARD).

Design, setting, and participants: This retrospective multicenter case series included 33 patients treated across 3 academic medical centers between December 2021 and January 2024. Eligible participants were those receiving hdVD (100 000 international units) for TEC or ARD with at least 10 days of follow-up.

Exposures: One or 2 oral doses of 100 000 international units of cholecalciferol or ergocalciferol.

Main outcomes and measures: The primary outcomes were time to patient-reported symptomatic relief and clinician-assessed objective improvement in erythema (using a 5-point Likert scale). Secondary outcomes included changes in serum calcium and the ability to continue anticancer therapy.

Results: Among 33 patients (mean [SD] age, 60.9 [14.6] years; 19 [58%] female), 28 (85%) had TEC and 5 (15%) had ARD. Subjective symptom relief was reported by 26 of 30 patients (87%) within 10 days of treatment. The median (range) time to improvement was 5 (1-28) days overall and 3 (1-16) days for the inpatient subgroup. The mean (SD) Likert erythema score decreased from 4.36 (0.60) at baseline to 2.21 (1.36) by day 10. Patients with neutrophilic eccrine hidradenitis and Stevens-Johnson syndrome/toxic epidermal necrolysis-like subtypes showed the most rapid responses. No meaningful changes in serum calcium levels were observed, and 24 of the 33 patients (73%) continued anticancer therapy without interruption. No treatment-related adverse events were reported during the study.

Conclusions and relevance: In this case series, hdVD was associated with rapid symptomatic and objective improvement in chemotherapy- and radiation-induced toxic effects of the skin without treatment-related adverse events. These findings support further study of hdVD as a supportive care approach in oncodermatology.