858 ABSENCE OF ISOLATED TESTICULAR RELAPSE (ITR) IN CHILDHOOD ACUTE LYMPHOBLASTIC LEUKEMIA (ALL) WITH A REPETITIVE REINDUCTION PROTOCOL

Abstract

ITR has emerged as a major new problem in children with ALL both on and off therapy. Post treatment overt ITR up to 40% and a 10-30% incidence of occult ITR (by testicular biopsy) has been reported. Our data is in sharp contrast to the published reports of ITR. We have not encountered ITR as the sole initial relapse in any of 107 boys with ALL treated at our institution over an 11 year period. 10 patients had mediastinal mass at presentation and 41 had WBC > 20,000/mm³ at diagnosis. All were treated for 5 yrs. with identical chemotherapy. In addition, the last 68 patients received Intermittent Intrathecal Methotrexate (MTX) and Fractional Irradiation (IMFRA) Central Nervous System (CNS) prophylaxis. Remission was induced with Vincristine (VCR) 2 mg/M² , 6-Mercaptopurine (6-MP) 2.5 mg/kg, and Prednisone (Pred) 60 mg/M² , and maintained with alternating cycles of biweekly oral MTX 30 mg/M² for 6 weeks, and VCR + 6-MP + Pred for 4 weeks. IMFRA CNS prophylaxis is given every 10 weeks. The median duration of complete remission was 18 mos. (range 1-120 mo.) for patients not receiving CNS prophylaxis, and it has not yet been reached (> 33 mos.; range 1-95 mos.) in those receiving CNS prophylaxis. Five of 26 patients off therapy had relapse, but none in the testes. This suggests that an effective maintenance program such as the repetitive reinduction protocol described above prevents ITR and that testis may not be a sanctuary site.

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