Fractionated cylophosphamide and back to back high dose methotrexate and cytosine arabinoside improves outcome in patients with stage III high grade small non-cleaved cell lymphomas (SNCCL): a randomized trial of the Pediatric Oncology Group.

BACKGROUND: The Pediatric Oncology Group (POG) conducted a two-arm, randomized study for the treatment of children and adolescents with stage III small, non-cleaved cell lymphoma (SNCCL). Regimen A, based on the group's previous best treatment for this group of patients, included cyclophosphamide (CTX) and high-dose methotrexate (MTX), as well as vincristine (VCR), prednisone (PRED), and intrathecal (IT) chemoprophylaxis. Regimen B, based on a single institution pilot study (Total B therapy), consisted of two rapidly alternating chemotherapy combinations (CTX, VCR, doxorubicin; MTX, and cytarabine (Ara-C) plus coordinated IT chemotherapy. PROCEDURE: One hundred thirty-four consecutive patients were entered on this study. Seventy patients were randomized to Regimen A, and 64 patients to Regimen B. One hundred and twenty-two patients are eligible for response. RESULTS: Complete remission (CR) was achieved by 81% (52/64) of patients on Regimen A, and 95% (55/58) of patients on Regimen B (p=0.014 one-sided). The two-year event-free survival (EFS) is 64% (SE=6%) on Regimen A, and 79% (SE=6%) on Regimen B (p=0.027 by one-sided logrank test). No patient has relapsed on either regimen after a year from diagnosis, although one patient had a second malignancy at day 371. Severe, but manageable, hematologic toxicity was seen in the majority of patients on both regimens, but was more frequent on Regimen B. CONCLUSIONS: We conclude that the cure rate in stage III SNCCL is significantly improved with the use of a short, six-month chemotherapy regimen of fractionated CTX alternated with coordinated MTX and Ara-C. Results suggest that drug schedule, not simple drug selection, influences outcome.