Autologous Testicular Tissue Transplantation

Freezing testicular tissue of prepubertal boys is a method for preserving spermatogonial stem cells in case of imminent gonadotoxic treatment during childhood. In case of total azoospermia or absence of spermatozoa that can be used for intra-cytoplasmic injection (ICSI) in adulthood, the investigators intend to perform the first in men autologous testicular tissue transplantation to restore fertility.

Freezing testicular tissue of prepubertal boys is a method for preserving spermatogonial stem cells. In 2002, the University hospital in Brussels (UZB) was the first hospital worldwide to offer testicular tissue cryobanking for fertility preservation in boys and ado-lescents. Since then, several other centers in Europe and USA have implemented similar fertility preservation programs. However, up till now, autologous transplantations of cryopreserved testicular tissue have not been performed yet. As soon as a patient returns to the Centre for Reproductive Medicine at UZB with the request to transplant the preserved testicular tissue, the investigators will first analyse semen and blood. If spermatozoa are found in their semen, men can immediately enroll in standard care for natural conception, intra-uterine insemination (IUI), in-vitro fertilization (IVF) or intra-cytoplasmic injection (ICSI). However, if no spermatozoa suitable for ICSI are detected in the ejaculate, the investigators intend to propose and eventually perform autologous testicular tissue transplantation with the primary objective being to restore spermatogenesis and fertility.

The eligible patients opted as a prepubertal boy to enroll in the fertility preservation program and on the moment of cancer diagnosis or hematological disorder, their parents have agreed to cryopreserve testicular tissue for later autologous transplantation. Inclusion Criteria: * At least 18 years old * In case of female partner, age \< 43 year * Absence of spermatozoa that can be used for ICSI on 2 semen analyses * Normal standardised preliminary and preoperative bloodsampling results * Complete remission of the oncological or hematological disease * Approval of the treating oncologist or other specialist in case of non-oncological disease as reason for the testicular tissue preservation as a child * Risk for presence of malignant cells in testicular tissue is negligible (according to multidisciplinary assessment) * Presence of spermatogonial stem cells (positive MAGE staining) in one or two of the thawed fragments (If absence of spermatogonial stem cells in two of the thawed fragments, the case will be discussed multidisciplinary) * Written informed consent for the transplantation of cryopreserved testicular tissue and follow-up after the procedure and of children born eventually after this procedure Exclusion criteria: * Risk for presence of malignant cells in the testicular tissue * Contra-indication for surgery * Contra-indication for pregnancy in the female partner * BMI \> 32 * Heavy smoking (≥10 cigarettes/day) * Instable psychological condition