長期精子凍結保存の現状と問題点 : 日本のプライベートホスピタルでの5年間の経験

Abstract

Private hospitals in Japan appear to play an important role in the fertility preservation in cancer patients. However, only a few university-related institutions have published their data about sperm banking. Here we report our experience in a private hospital. The database of 5 years of experience with sperm cryopreservation for male cancer patients was reviewed. We assessed the type of cancer, timing of collection, sperm quality, and utilization for reproductive purposes. There were a total of 88 oncology patients who underwent sperm banking at our institution during the study period. Types of cancer were various, with testicular cancer and hematological malignancies comprising the largest groups. Nearly 90% of the testicular cancer patients had their sperm preserved prior to the therapy, while only 53% of those with hematological disease did so. Evaluation of semen parameters for these groups revealed that oligozoospermia in testicular cancer patients, even prior to initiation of cancer therapy, was common. Five patients utilized their specimens for reproductive purposes. Of these, 3 patients successfully fathered a child. Our results suggest that sperm cryopreservation before initiation of cancer therapy in male oncology patients is under-utilized. Additionally, there is minimal use of cryopreserved specimens for reproductive purposes. This under-utilization is supposed to be due to physicians', especially hematologists', insufficient awareness toward chemotherapy-related infertility and the paucity of reports regarding reproductive outcome after freezing. More data should be compiled to help both physicians and patients who are considering sperm cryopreservation.

京都市内で生殖医療を専門とした診療を行っている個人病院における長期精子凍結保存の実施状況を調査・検討した。解析対象は過去5年間に長期凍結保存を行った88症例とした。患者は全て他院からの紹介であり、紹介元の地域分類では京都府内が76%と最も多かったが、滋賀県や奈良県、さらには愛知県からの紹介もみられた。紹介患者の平均年齢は28.4歳で、未婚者が7割以上を占めていた。原疾患では精巣腫瘍が37.5%、血液疾患が44.3%を占めていた。紹介を受けたタイミングは、化学療法前の紹介が精巣腫瘍で9割近くに達していたが、血液疾患では約5割にとどまっていた。精液所見は乏精子症を34% に、精子無力症を57%に認めた。観察期間内に5例(4例は化学療法施行前に保存)で凍結精子を使用し、3例が妊娠・出産に至った。化学療法が生殖機能に及ぼす影響を詳細に検討するためにも、患者の定期フォローを可能にする体制が必要であると考えた。