Chemotherapy plays a major role in the inhibition of catch-up growth during maintenance therapy for childhood acute lymphoblastic leukemia.

OBJECTIVE In children treated for acute lymphoblastic leukemia (ALL), catch-up growth occurs after cessation of therapy and not during maintenance therapy. In this study we investigated whether this inhibition of catch-up growth during maintenance treatment is attributable to the influence of chemotherapy or to the influence of corticosteroids. PATIENTS Forty-six children treated for ALL were included in the study. In 27 patients maintenance therapy comprised vincristine (VCR), prednisone (Pred), or dexamethasone (Dexa) alternated with 6-mercaptopurine (6-MP) and methotrexate (MTX) and 19 patients received maintenance therapy with 6-MP and MTX only. Treatment did not include cranial irradiation. RESULTS Statural growth during maintenance treatment was comparable in both groups over the study period of 1.5 years. CONCLUSION Chemotherapy with 6-MP and MTX, and not corticosteroids, is the main factor that prevents catch-up growth from occurring during maintenance therapy for ALL.