Development of the testis in pre-pubertal boys with cancer after biopsy for fertility preservation.

STUDY QUESTION: Is testicular growth affected by a testicular biopsy intended for fertility preservation in pre-pubertal boys with cancer?

SUMMARY ANSWER: Testicular growth of the biopsied testis is not impeded in comparison to the non-biopsied contralateral testis up until 1 year after surgery.

WHAT IS KNOWN ALREADY: Fertility preservation in pre-pubertal boys by means of testicular biopsy has been conducted for more than 15 years. Although immediate adverse effects of testicular biopsy are rare (1%), no data exist on the effect of biopsy on testicular growth.

STUDY DESIGN, SIZE, DURATION: In this prospective cohort study, between March 2011 and February 2017, 93 parents of pre-pubertal boys were offered cryopreservation of testicular tissue of their son, of whom 78 consented. Sixty-four boys were included in this follow-up study.

PARTICIPANTS/MATERIALS, SETTING, METHODS: All boys with cancer at the paediatric oncology department of the Academic Medical Center (AMC) who needed gonadotoxic therapy and were unable to ejaculate were offered cryopreservation of testicular tissue prior to treatment. By testicular ultrasound before and after biopsy (1, 6 and 12 months after biopsy), volume and parenchymal abnormalities were assessed. Data were analysed using mixed-effects modelling.

MAIN RESULTS AND THE ROLE OF CHANCE: Of the 64 included boys all were followed up at 1 month, 58 at 6 months and 55 at 12 months. Mean testicular volumes after 1, 6 and 12 months after biopsy were 1.7 ± 2.1, 1.7 ± 2.2 and 1.9 ± 2.4 for the biopsied testis and 1.8 ± 2.2, 1.8 ± 2.3 and 2.0 ± 2.2 for the non-biopsied testis, respectively. Biopsy of the testis did not have a significant impact on testicular growth. Immediate adverse effects of the biopsy, i.e. wound infections, were seen in 3/78 boys (3.8%).

LIMITATIONS, REASONS FOR CAUTION: Although it is the largest cohort available to date, the number of patients included in our follow-up is still relatively small. A larger cohort would be able to evaluate growth more precisely. Follow-up was discontinued in a significant portion of boys, 12/76 (15.8%), mainly because of death due to primary illness but also because they could not be reached or declined further follow-up.

WIDER IMPLICATIONS OF THE FINDINGS: These reassuring data may be used in counselling future boys who are eligible for fertility preservation and their parents.

STUDY FUNDING/COMPETING INTEREST(S): Study funded by KIKA Foundation (Kika 86), Grant from the Netherlands Organisation for Health Research and Development (ZonMW TAS-116003002). The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER: CCMO-register: NL27690.000.09.