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

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.

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).

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.

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

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.

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.

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.