Treatment with oral or topical sirolimus in complex vascular anomalies in pediatrics. Experience in a third-level hospital.

Objective: The use of sirolimus in vascular anomalies is a special indication not authorized in its data sheet. The objective of this study was to increase the evidence of oral or topical use of sirolimus for this indication in the pediatric population.

Materials and methods: An observational, retrospective study of patients under 18 years of age treated with oral or topical sirolimus for vascular anomalies was carried out. Diagnosis and location of lesions, administration route and dosage of sirolimus, blood levels of sirolimus in patients who received oral treatment, treatment duration, response, and toxicity were collected.

Results: 18 patients - 7 with oral treatment and 11 with topical treatment - were included. With oral sirolimus, the overall response rate was 85.7%. Sirolimus was discontinued in 2 cases - as a result of full resolution and progression. 57.1% of patients had adverse effects, most of which were mild. Dyslipidemia was the most frequent adverse effect. Blood levels were monitored in all patients for dose adjustment purposes. With topical treatment, the overall response rate was 72.7%. Sirolimus was discontinued in 3 cases -due to progression in 2 cases and to stability in 1. 27.3% of patients had adverse effects, with itching standing out as the most frequent one.

Conclusions: The favorable results of sirolimus treatment in our patients seem to confirm its effectiveness and safety in vascular anomalies, which make it stand as a therapeutic option in pediatric patients. However, further research is required to establish the optimal treatment regimen, treatment duration, and potential long-term adverse effects.