精子保存对癌症患者的意义

　　Hodgkin’s disease, testicular cancer, leukemia, and non-Hodgkin’s lymphoma are the most common malignancies seen in men of reproductive age (1). Sperm quality in men diagnosed with testicular tumors is suboptimal, even prior to the initiation of chemo/radiotherapy, due to in part the local negative effects exerted by the tumors. In one study, sperm concentration was significantly lower in patients with a testicular malignancy than in those with systemic malignancy and healthy donors with proven fertility. Motility was found to be significantly lower in patients with testicular and systemic malignancy than in healthy proven fertile donors (2).

　　霍齐金病，睾丸癌，白血病和非霍齐金淋巴瘤是育龄男性中最常见的恶性肿瘤(1)。睾丸肿瘤患者的精子质量并不理想，即使在开始化疗/放射治疗之前也不乐观，导致这种情况的部分原因是肿瘤产生的局部负面影响。一项研究发现，恶性睾丸肿瘤患者的精子浓度显著低于系统性恶性肿瘤患者和已经有过生育史的健康捐赠者。此外，睾丸肿瘤患者和全身恶性肿瘤患者的精子活动率显著低于已经有过生育史的健康捐赠者(2)。

　　Anti-neoplastic therapy is associated with significant morbidity, and testicular dysfunction is among the most common long-term side effects of cytotoxic chemotherapy in men. Cancer patients receiving radiotherapy are at high-risk for developing infertility and cancer surgery can reduce sperm concentration, causing erectile dysfunction (3). Between 15 and 30 percent of male patients undergoing gonadotoxic treatments do not regain fertility (4). Most patients undergoing chemotherapy develop azoospermia by 12 weeks.

　　抗肿瘤治疗与严重的并发症有关，其中睾丸功能障碍是男性接受细胞毒性化疗最常见的长期副作用之一。接受放疗的癌症患者发生不孕症的风险很高。癌症手术会降低精子浓度，导致勃起功能障碍(3)。接受性腺毒性治疗的患者中有15%至30%的人无法恢复生育功能(4)。大多数接受化疗的患者在治疗12周时会出现无精症。

　　The degree to which testicular function is affected depends on the dose and agent (5). Alkylating agents (e.g. cyclophosphamide and busulfan) and ionizing radiation frequently induce azoospermia, rendering the patient infertile. A major reason to freeze sperm before treatment is the concern for potential chromosomal aberrations in sperm that are exposed to chemotherapy (6). Although no increase in malformation rates have been reported in children born to patients who have had chemotherapy or radiotherapy, the available data and follow-up are still limited.

　　睾丸功能的受损程度取决于使用的药剂和剂量(5)。烷化剂(例如环磷酰胺和白消安)和电离辐射经常容易引起无精症，导致患者不育。在治疗前冷冻精子的一个主要原因是担心暴露于化学疗法的精子有潜在的染色体畸变(6)。尽管没有研究发现接受化疗或放疗的患者所生儿童在畸形率上有增加，但是可用的数据和随访仍然有限。

　　Chemotherapy targets cells outside the G0 phase, destroying proliferating spermatogonias (7). The majority of chemotherapy patients develop azoospermia during treatment, and it is difficult to predict if and when spermatogenesis will recover. Recovery tends to be dose dependent. Patients receiving low doses of these agents may recover spermatogenesis with 12 weeks after completing chemotherapy. However more than 50 percent of patients will receive high dose chemotherapy and may contribute to the 15-30 percent of all patients who remain sterile in the long term It is estimated that up to 15 percent of male patients will already be azoospermic before undergoing any type of treatment. Semen should be cryopreserved before cancer treatment begins. It is optimal to have multiple samples cryopreserved (8). Patients who are most at risk are those who undergo a treatment that includes successive and multiple toxicities, such as bone marrow transplantation (9).

　　化疗针对G0期以外的细胞，会破坏增殖期的精原细胞(7)。大多数化疗患者在治疗期间会出现无精症，很难预测是否以及何时会恢复精子生成，这跟治疗剂量有关。接受低剂量治疗的患者可能会在完成化疗12周后恢复精子生成。但是超过50%的患者需要接受高剂量化疗，可能导致15-30%的患者长期处于不育状态。据估计，高达15%的男性患者在接受任何类型的化疗之前已经有无精症。精液应在癌症治疗开始前进行冷冻保存，且冷冻保存多个样本是最佳选择(8)。接受诸如连续或多重毒性治疗如骨髓移植的患者面临无精症的风险最高。

　　References

　　参考文献

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　　2. Williams DH, Karpman E, Sander JC, Spiess PE, Pisters LL, Lipshultz LI. Pretreatment semen paraments in men with cancer. J Urol 2009; 181(2):736-40.

　　3. Nijs M, Vanderzwalmen P, Vandamme B, Segal-Bertin G, Lejeune B, Segal L, et al. Fertilizing ability of immotile spermatozoa after intracytoplasmic sperm injection. Hum Reprod 1996; 11(10):2180-5.

　　4. Menon S, Rives N, Mousset-Simeon N, Sibert L, Vannier JP, Mazurier S, et al. Fertility preservation in adolescent males: experience over 22 years at Rouen University Hospital. Hum Reprod 2009;24(1):37-44.

　　5. Palermo G, Joris H, Devroey P, Van Steirteghem AC. Pregnancies after intracytoplasmic injection of single spermatozoon into an oocyte. Lancet 1992;340(8810):17-8.

　　6. Lass A, Akagbosu F, Brinsden P. Sperm banking and assisted reproduction treatment for couples following cancer treatment of the male partner. Hum Reprod Update 2001; 7(4):370-7.

　　7. Bonetti TCS, Pasqualotto FF, Queiroz P, Iaconelli A Jr, Borges E J. Sperm banking for male cancer patients: social and semen profiles. Int Braz J Urol 2009;35(2):190-7.

　　8. Bonetti TCS, Pasqualotto FF, Queiroz P, Iaconelli A Jr, Borges E J. Sperm banking for male cancer patients: social and semen profiles. Int Braz J Urol 2009;35(2):190-7; discussion 7-8.

　　9. de Vries MC, Bresters D, Engberts DP, Wit JM, van Leeuwen E. Attitudes of physicians and parents towards discussing infertility risks and semen cryopreservation with male adolescents diagnosed with cancer. Pediatr Blood Cancer 2009;53(3):385-91.