Long-term outcomes of elective human sperm cryostorage

BACKGROUND: Sperm cryopreservation allows men with threatened fertility to preserve their progenitive potential, but there is little data on long-term outcomes of elective sperm cryostorage programmes. METHODS AND RESULTS: Over 22 years, 930 men sought semen cryostorage in a single academic hospital, of which 833 (90%) had spermatozoa cryostored. Among 692 (74%) men surviving their illness, sperm samples were discarded for 193 (21% of all applicants, 28% of survivors) and cryostored spermatozoa were used for 64 men (7% of all applicants, 9% of survivors) in 85 treatment cycles commencing at a median of 36 months post-storage (range 12-180 months) with nearly 90% of usage started within 10 years of storage and none after 15 years. Pregnancy was most efficiently produced by intracytoplasmic sperm injection (median three cycles) compared with conventional IVF (median eight cycles) or artificial insemination (median more than six cycles; P < 0.05). A total of 141 (15%) of men had died and of these, 120 (85% of those dying) had their spermatozoa discarded; requests to prolong cryostorage were received from relatives of 21 men (2% of all applicants, 15% of deceased) of which three cases had spermatozoa transferred for use with no pregnancies reported. Sperm concentration was lower for all cryostorage groups compared with healthy sperm donor controls (P < 0.05). Following orchidectomy, men with testicular cancer had sperm density approximately half that of all other groups of men seeking cryostorage (P < 0.05), the lowering attributable to removal of one testis rather than in defects in spermatogenesis. CONCLUSION: Elective sperm cryopreservation is an effective, if sparsely used, form of fertility insurance for men whose fertility is threatened by medical treatment and is an essential part of any comprehensive cancer care programme.