Patients and methods
We performed a retrospective analysis of case records of children less than 18 years of age, diagnosed to have IMFT in the department of pediatric hemato-oncology, from January 2014 till May 2020. The diagnosis was confirmed through morphology and immunohistochemistry (IHC) of an image-guided trucut biopsy of the lesion or review of the excised tissue in those who underwent surgery. The extent of disease required imaging with either computed tomography (CT) or Positron emission tomography-computed tomography (PET-CT) as indicated. All cases were discussed in a multidisciplinary tumor board before initiating treatment. Written informed consent was obtained from all families, and the institutional review board has approved the study.
The oral combination chemotherapy regimen included prednisolone at 1 milligram/kilogram/day (mg/kg) in two to three divided doses, 6-mercaptopurine (6-MP) started at 25 mg once a day in all children and dosage titrated based upon serial absolute neutrophil counts (ANC) such as to maintain an ANC of 750 – 1500/cu.mm, methotrexate at 20 mg/square meter once a week and celecoxib at 50 mg once a day in those between 10-25 kgs, and 100 mg once a day in those weighing >25kg. All children were monitored for adverse effects with regular assessment for complete blood counts, liver enzymes, and serum creatinine. Response assessment was performed for all children at four weeks of initiating the above chemotherapy. When required, crizotinib was administered at a dose of 280 mg/square meter/day (5).