Sperm cryopreservation prior to gonadotoxic treatment: experience of a single academic centre over 4 decades

STUDY QUESTION: What is the natural history of outcomes of sperm cryostorage at an Australian tertiary academic centre? SUMMARY ANSWER: Cryostorage is feasible in virtually all men facing gonadotoxic therapy but the timing of sperm disposal varies according to the reason for it. WHAT IS KNOWN ALREADY: Gonadotoxic treatment for cancer or non-cancer diseases damages spermatogenesis and impairs male fertility. Sperm cryopreservation is an established technique to preserve male fertility prior to gonadotoxic treatment. STUDY DESIGN, SIZE, DURATION: A retrospective review of clinical, anthropometric, semen analysis and hormonal data from 1978 to 2017 involving 2717 men comprising 2085 men with cancer, 234 non-cancer disease and 398 healthy controls, in a single tertiary academic centre with the same clinic and laboratory staff. PARTICIPANTS/MATERIALS, SETTING AND METHODS: Sperm output was analysed according to diseases, the feasibility of sperm cryostorage notably for adolescents, regional access to an urban cryostorage facility, the determinants of sperm output and time-dependent disposal of cryostored sperm. Semen samples were assessed by contemporaneous WHO methods. MAIN RESULTS AND THE ROLE OF CHANCE: Of 2085 men with cancer, 904 (43%) had haematological malignancies, 680 (33%) testicular cancers and 136 (6.5%) were adolescents. Most men (89%) and adolescents (80%) could collect sperm. Sperm output for all cancers and non-cancer diseases was lower than controls. Sperm output correlated positively with total testicular volume (r = 0.44, P < 0.0001) and negatively with serum FSH and LH (r = -0.24, -0.12, respectively, both P < 0.0001) but not testosterone. For all stored samples, the median time in cryostorage was 8.5 years, 7% were transferred for use to induce pregnancy (median time 2.5 years) and 62.2% were discarded as no longer needed (return of fertility, 35.9% median 3.5 years; death, 26.3%, median 6.5 years), the high disposal rate reflecting regular annual follow-up to establish ongoing need for continued cryostorage. Cryostorage facilities are not available in remote and rural areas of the State and the proportion of outer regional and remote area residents cryostoring sperm was only about half that compared with urban residents. LIMITATIONS, REASONS FOR CAUTION: This study does not report the pregnancy outcomes of the patients who used the cryostored sperm, due to recent limitations on health data privacy. WIDER IMPLICATIONS OF THE FINDINGS: Sperm cryostorage is feasible for virtually all men, including sufficiently mature adolescents, who can collect semen to insure future paternity as well as making positive psychological preparation for the patient's survival. Disposal of cryostored material when no longer required is efficient with regular follow-up. Sperm cryopreservation should be an integral part of comprehensive treatment plan in men receiving gonadotoxic treatment but remains underutilized. STUDY FUNDING/COMPETING INTEREST(S): There was no external funding for this study and there were no relevant conflicts of interest.