Efficacy of Initial Sirolimus Therapy for 27 Patients with Intractable Lymphatic Malformations.

OBJECTIVE/HYPOTHESIS To evaluate the efficacy of initial sirolimus therapy in the treatment of intractable head and neck lymphatic malformations (LMs) in children. STUDY DESIGN Prospective open-label study. METHODS In this study, Twenty-seven children diagnosed with LMs were given oral sirolimus as primary treatment over a minimum 6-month trial. The major parameter to evaluate therapeutic outcome was percentage of lesion volume change compared with baseline. Average serum sirolimus concentrations, and adverse side effects, were monitored throughout the study period. RESULTS Fifteen girls and twelve boys, average age 27 months (16 days-171 months), constitute the study group. Treatment was deemed effective for twenty-three participants, judged as fair in seven, good in nine, and excellent in seven. Two patients had minimal improvement, and two had increased volume to some degree. Effectiveness differed among LMs subtypes with responsiveness of macrocystic LMs exceeding that of microcystic LMs (P < .05). Adverse drug reactions totaled 27 events in ten patients, the majority being mild with upper respiratory infections being most common. CONCLUSIONS Sirolimus as initial therapy is effective in decreasing lesion volume in intractable LMs in head and neck region, especially in macrocystic subtypes. Although most cases cannot be completely cured, side effects are few and tolerable. LEVEL OF EVIDENCE IV Laryngoscope, 2021.