Background
Vascular tumors associated with Kasabach-Merritt phenomenon could induce significant morbidity because of progressive thrombocytopenia and coagulation disorders. Corticosteroids are considered to be the primary choice for drug therapy. However, the recurrence rate is generally high after the treatment has stopped and there are many steroid-resistant cases. It’s really challenging to treat these steroid-resistant cases. In the present study, analyzed data are presented to support the application of rapamycin therapy in clinical practice for steroid-resistant vascular tumors with Kasabach-Merritt phenomenon in infants.
Methods
Clinical data of eight infants with steroid-resistant vascular tumors associated with KMP treated between June 2015 and April 2016 in a single hospital were retrospectively analyzed. All Patients received the therapy of rapamycin. Rapamycin was started at a dose of 0.8mg/m², administered twice daily at approximately 12-hour interveals to maintain through levels of 10~15ng/ml. The dose of rapamycin could be modulated according to the level of rapamycin, the count of platelet, the shrinkage of the lesion and the side effects, which were monitored regularly during the study. Results
There were significant improvements in clinical status, including platelet increasing, coagulation function improvement and tumor shrinkage. Steroids were withdrawn quickly. Time to initial response was (6.8±2.7) days. Average stabilization time of platelet was (19.1±8.5) days. Average duration of rapamycin treatment was (6.0±2.2) months and the average time for rapamycin treated as a single agent was（4.5±1.9）months. There was no symptomatic relapse. The side effects were tolerable, such as oral ulcer, fever, pain, skin rash, transient ascension of serum transaminase and cholesterin.
Conclusions
Rapamycin therapy for infants with steroid-resistant vascular tumors associated with Kasabach-Merritt phenomenon is a safe, useful and effective method. It might be worthy of clinical application widely.