Back to Fall Congress

BACKGROUND:
Gonadal damage is an unfortunate treatment related consequence for pediatric malignancies and some other non-malignant conditions treated with stem cell transplant. Prepubertal males pose a challenge for fertility preservation as these boys cannot produce semen for cryopreservation. Testicular tissue cryopreservation is a potential option for this cohort. Although successful in animal models, translational use in humans remains experimental. We report on a single institution’s 5-year experience to date with a pilot protocol aimed at offering testicular biopsy and cryopreservation to families of prepubertal boys at highest risk for long term gonadotoxicity and infertility. During this time, remarkable basic science progress has been made to isolate and increase the number of spermatogonial stem cells (SSCs) available to be transplanted, a key component in ultimately translating this fertility science to achieve live human births with this cryopreserved tissue.
METHODS:
Parents of prepubertal boys with high-risk diagnoses were offered testicular cryopreservation (diagnoses including: high risk neuroblastoma, rhabdomyosarcoma, osteosarcoma, Ewing sarcoma, histological variants of these sarcomas treated with sarcoma-like therapy, unknown final pathology with small round blue cells on frozen section, patients preparing for stem cell transplant for treatment of hematological disorders or certain immunodeficiencies). Patients with a coagulopathy, cryptorchidism, or testicular involvement of their tumor were excluded. Half of the biopsy was frozen for the subject’s potential future use. The remainder was used for histologic evaluation of the germ cells and to refine the laboratory science required for successful expansion of human SSCs. Post-biopsy, patients were followed for acute side effects.
RESULTS:
Since January 2008, 63 prepubertal boys and their families were approached regarding entry into the study. Fifty-one families (81%) consented to the testicular biopsy; 43 of 51 underwent the procedure (8 patients had non-malignant diagnoses). No patients had serious morbidity with the biopsy. There was one post-operative scrotal cellulitis successfully treated with antibiotics in a 17 month old boy who was being transplanted for an immunodeficiency. There were no other post-operative infections, no bleeding issues, and no reports of excessive pain documented. Although the time at diagnosis is stressful, families are able to give thoughtful consideration to this option for potential fertility preservation. Basic science advances for restoring fertility with SCCs in cryopreserved testicular tissue has shown significant progress in a variety of animal models, and there is initial progress in culturing these cells from the testes of prepubertal boys.
CONCLUSIONS:
With the proper infrastructure and interdisciplinary team, cryopreservation of testicular tissue from prepubertal boys diagnosed with cancer can be done successfully. Testicular biopsy for this purpose can be performed safely in this cohort without any significant acute toxicity. Given the encouraging results of SSC preservation in animal models and the advances in the basic and translational science of testicular tissue cryopreservation over the past 5 years, it is reasonable to continue to offer this option to families within the context of a formal research protocol for potential fertility preservation.