Fifty-seven children with acute lymphoblastic leukemia (ALL) receiving therapy who experienced overt isolated testicular relapse while in bone marrow remission were entered into a study that featured an intensive retreatment regimen.

The objective was to determine whether a change in chemotherapy and local irradiation would prevent subsequent marrow relapse and increase the survival rate. The regimens used (modified Berlin-Frankfurt-Munster or modified New York) delivered acceptable therapy based on analyses of toxicity data.

Overall survival at 5 years from the time of testicular relapse was 47%, with an event-free survival of 43%. Events have been documented in 28 of 55 evaluable children. Analysis of these patients revealed that 23 children had bone marrow relapse, 4 children had central nervous system relapse, and 1 child had testicular relapse. In addition, two patients were removed from the study for toxicity, one child for infection (mucormycosis), and five children had a bone marrow transplantation while in remission and became ineligible to continue in the study. Two children were removed at the request of their parents, and nine children were lost to follow-up.

Because of their high risk of developing systemic relapse, boys with ALL who experience isolated overt testicular relapse during active therapy should be retreated with intensive treatment.