Long-term survival in childhood acute leukemia: "late" relapses.

The "late" relapse patterns of childhood acute leukemia were studied in 83 children in their first continuous complete remission for more than three years prior to randomization for stopping therapy (40 patients) or continuing therapy (43 patients) for a total of six years. Twenty of 83 (22.9%) have relapsed: Ten in the bone marrow, one in the central nervous system, and nine in the testes. The testes relapse rate of 41.1% (7/17) in males discontinuing therapy at three years was much higher than that of 8.7% (2/23) in males continuing therapy. This difference is significant at P = 0.01 (Wilcoxon test).