低风险或中度风险的性腺毒性化疗对（青春前）睾丸组织冷冻（TTF）前接受的精原细胞数量以及癌症本身对（青春前）男孩睾丸组织精原细胞数量的影响是什么？当与烷化剂结合时，长春新碱对精原细胞数量有额外的不良影响，而卡铂对精原细胞数量无独立贡献，与接受非烷化剂化疗的患者相比，它对（青春前）男孩睾丸组织的精原细胞数量没有影响。癌症治疗后改善的生存率需要将生育保护程序纳入综合护理的一部分，考虑到患者的年龄。精子冷冻保存是青春期后男性已确立的程序，而对于（青春前）男孩，TTF仍然是试验性的。几项研究探索了TTF后（青春前）男孩睾丸组织的管状生育指数（TFI，包含精原细胞的精索小管截面百分比）和每个精索小管截面的精原细胞数量（S/T）。所有研究均显示，TFI和S/T在引入化疗药物后总是下降，特别是那些具有高性腺毒性风险的化疗药物，如烷化剂。从2009年5月至2014年6月，从6个月到16岁的79名（青春前）男孩的癌症诊断的睾丸组织样本进行了冷冻保存。记录了他们的医学诊断和先前的化疗暴露。我们对（青春前）睾丸组织的组织学切片进行了检查，以阐明化疗或原发诊断对TFI和S/T的影响。将癌症诊断患有TTF之前为HSC移植进行调理治疗的（青春前）男孩纳入研究。所有患者之前曾接受对未来生育低或中风险的化疗。我们选择了化疗信息完整的患者。通过形态和免疫组织化学分析评估了精原细胞的数量和睾丸组织的质量。观察到接受烷化剂治疗的男孩精原细胞数量明显减少。接受烷化剂治疗的男孩的平均S/T值明显低于接受非烷化剂治疗的男孩（P = 0.018）。相反，接受卡铂作为唯一烷化剂治疗的患者与接受非烷化剂治疗的患者组之间没有差异。我们观察到，未接受任何烷化剂治疗的患者的S/T随年龄增加而增加，而使用于环磷酰胺等剂量相当的烷化剂治疗的患者的S/T随年龄减少（分别为r = 0.6166，P = 0.0434；r = -0.3759，P = 0.0036）。在接受长春新碱联合烷化剂治疗的患者组中，TFI和S/T进一步下降（22.4％的降低，P = 0.0049和P <0.0001，分别），但在该组中，CED显著增加（P <0.0001）。多元分析在CED调整后显示，长春新碱的使用与TFI的减少相关（P = 0.02）。本研究是对可能导致不育风险的（青春前）男孩的睾丸组织的描述性研究。研究人群相当异质，每个子组中的患者数量较少。我们的结果是基于接受烷化剂治疗的患者与接受非烷化剂治疗的患者之间的比较，而不是与化疗未接触的患者之间的比较。法国国家癌症预防指南建议在高度性腺毒性治疗之前进行TTF。因此，所有患者在TTF之前都接受了低或中风险的性腺毒性化疗。无法获得来自化疗未接触的具有可比较的癌症组织类型的患者的睾丸组织样本。由于样本数量有限，无法通过移植或体外成熟测试精原细胞和体细胞的功能。本研究总结了（青春前）男孩在进行TTF之前的精原细胞数量。我们确认了累积烷化剂暴露与精原细胞数量之间的负相关。此外，长春新碱与烷化剂的协同使用对TFI具有累积的有害效果。对于需要生育保护的患者，应为预测的CED超过4000 mg/m2的化疗提出TTF。然而，需要在随后的研究中包括更多患者来确认长春新碱和卡铂的数据。本研究得到了法国国家癌症研究基金PHRC No. 2008/071/HP的资助，该基金由法国癌症研究所和法国医疗组织领取。赞助商在研究中没有任何角色。作者声明无利益冲突。N/A.© The Author(s) 2023. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

What is the impact of low- or moderate-risk gonadotoxic chemotherapy received prior to testicular tissue freezing (TTF), and of the cancer itself, on spermatogonia quantity in testicular tissue from (pre)pubertal boys?Vincristine, when associated with alkylating agents, has an additional adverse effect on spermatogonia quantity, while carboplatin has no individual contribution to spermatogonia quantity, in testicular tissue of (pre)pubertal boys, when compared to patients who have received non-alkylating chemotherapy.The improved survival rates after cancer treatment necessitate the inclusion of fertility preservation procedures as part of the comprehensive care for patients, taking into consideration their age. Sperm cryopreservation is an established procedure in post-pubertal males while the TTF proposed for (pre)pubertal boys remains experimental. Several studies exploring testicular tissue of (pre)pubertal boys after TTF have examined the tubular fertility index (TFI, percentage of seminiferous tubule cross-sections containing spermatogonia) and the number of spermatogonia per seminiferous tubule cross-section (S/T). All studies have demonstrated that TFI and S/T always decrease after the introduction of chemotherapeutic agents, especially those which carry high gonadotoxic risks such as alkylating agents.Testicular tissue samples from 79 (pre)pubertal boys diagnosed with cancer (from 6 months to 16 years of age) were cryopreserved between May 2009 and June 2014. Their medical diagnoses and previous chemotherapy exposures were recorded. We examined histological sections of (pre)pubertal testicular tissue to elucidate whether the chemotherapy or the primary diagnosis affects mainly TFI and S/T.(Pre)pubertal boys with cancer diagnosis who had been offered TTF prior to conditioning treatment for hematopoietic stem cell transplantation were included in the study. All the patients had previously received chemotherapy with low- or moderate-risk for future fertility. We have selected patients for whom the information on the chemotherapy received was complete. The quantity of spermatogonia and quality of testicular tissue were assessed by both morphological and immunohistochemical analyses.A significant reduction in the number of spermatogonia was observed in boys treated with alkylating agents. The mean S/T values in boys exposed to alkylating agents were significantly lower compared to boys exposed to non-alkylating agents (P = 0.018). In contrast, no difference was observed for patients treated with carboplatin as the sole administered alkylating agent compared to the group of patients exposed to non-alkylating agents. We observed an increase of S/T with age in the group of patients who did not receive any alkylating agent and a decrease of S/T with age when patients received alkylating agents included in the cyclophosphamide equivalent dose (CED) formula (r = 0.6166, P = 0.0434; r = -0.3759, P = 0.0036, respectively). The TFI and S/T decreased further in the group of patients who received vincristine in combination with alkylating agents (decrease of 22.4%, P = 0.0049 and P < 0.0001, respectively), but in this group the CED was also increased significantly (P < 0.0001). Multivariate analysis, after CED adjustment, showed the persistence of a decrease in TFI correlated with vincristine administration (P = 0.02).This is a descriptive study of testicular tissues obtained from (pre)pubertal boys who were at risk of infertility. The study population is quite heterogeneous, with a small number of patients in each sub-group. Our results are based on comparisons between patients receiving alkylating agents compared to patients receiving non-alkylating agents rather than chemotherapy-naive patients. The French national guidelines for fertility preservation in cancer patients recommend TTF before highly gonadotoxic treatment. Therefore, all the patients had received low- or moderate-risk gonadotoxic chemotherapy before TTF. Access to testicular tissue samples from chemotherapy-naive patients with comparable histological types of cancer was not possible. The functionality of spermatogonia and somatic cells could not be tested by transplantation or in vitro maturation due to limited sample sizes.This study summarizes the spermatogonial quantity of (pre)pubertal boys prior to TTF. We confirmed a negative correlation between the cumulative exposure to alkylating agents and spermatogonial quantity. In addition, the synergistic use of vincristine in combination with alkylating agents showed a cumulative deleterious effect on the TFI. For patients for whom fertility preservation is indicated, TTF should be proposed for chemotherapy with a predicted CED above 4000 mg/m2. However, the data obtained from vincristine and carboplatin use should be confirmed in a subsequent study including more patients.This study had financial support from a French national research grant PHRC No. 2008/071/HP obtained by the French Institute of Cancer and the French Healthcare Organization. The sponsors played no role in the study. The authors declare no conflicts of interest.N/A.© The Author(s) 2023. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.