Testicular relapse in childhood acute lymphoblastic leukemia: The challenges and lessons

Background : Relapse of disease is documented in 15-20% of children with acute lymphoblastic leukemia (ALL). Although testicular relapse is rare with modern risk-adapted treatment protocols, earlier, the testes were a frequently encountered site of relapse and were designated as "drug sanctuaries".
Purpose : This descriptive study was designed to assess the pattern of testicular relapse and to identify high-risk factors.
Materials and Methods : Data obtained from case records of 407 boys with ALL were analyzed. Fine needle aspiration cytology was carried out in children presenting with painless enlargement of testi(e)s. Bone marrow aspiration and cerebrospinal fluid examination were performed concomitantly to confirm or exclude disease at these sites.
Results : Testicular relapse was documented in 30 boys. It was isolated in 17 patients and associated with bone marrow and/or central nervous system relapse in 13. At relapse, nine boys were over the age of 10 years. The majority were very early and early relapsers. Hyperleucocytosis was documented in five of 30 and seven of 137 relapsers and nonrelapsers, respectively (P = 0.04). Twelve of the 30 boys with testicular relapse were treated with testicular irradiation, reinduction and maintenance therapy. The estimated median overall survival was 33 months.
Conclusion : Testicular relapse, which depends on the therapy administered, may manifest several months/years after completion of treatment. The high incidence of testicular relapse in our series implicates the need of revaluation of our protocol and incorporation of high/intermediate dose methotrexate therapy upfront.