Methotrexate and citrovorum factor rescue in the management of childhood lymphosarcoma and reticulum cell sarcoma (non-Hodgkin's lymphomas): parolonged unmaintained remissions.

High doses of methotrexate (HDMTX), given in pulse infusions of 3 to 30 mg/kg body weight, were studied in 22 children with non-Hodgkin's lymphoma. Sixteen complete and five partial remissions were observed in 21 patients evaluable for remission induction. The dose of MTX was increased stepwise on consecutive treatments until objective tumor response occured. Citrovorum factor rescue (CFR) was used "on demand" when toxicity started to develop, and routinely after 30 mg/kg of MTX. Twelve patients who had no previous chemotherapy were entered in a Phase II study consisting of remission induction with HDMTX and remission maintenance with monthly HDMTX supplemented with one monthly injection of vincristine and Cytoxan and five days of oral 6-mercaptopurine and prednisone. Eleven patients achieved remissions (eight complete and three partial) with HDMTX and one with surgery and radiation followed by HDMTX. The three partial remissions improved to complete remission during remission maintenance. All 12 were given the maintenance cyclic combination chemotherapy. Seven of the 12 patients entered the unmaintained phase of the study. One patient relapsed 6 months after cessation of therapy and died 4 years after diagnosis. Six patients are alive and free of disease 2 1/2 to 5 1/2 years after discountinuing treatment and 4 1/2 to 8 1/3 years after diagnosis. Five of these six patients had advanced (Stage IV) disease.