Testicular histology and function following long-term chemotherapy of acute leukemia in children and outcome of the patients who received testicular biopsy

Association of the minimal cyclophosphamide equivalent dose and outcome of microdissection testicular sperm extraction in patients with persistent azoospermia after chemotherapy

Objective

To investigate whether the minimal cyclophosphamide equivalent dose (mCED), a novel approach for estimating alkylating agent exposure, is associated with the sperm retrieval rates by microdissection testicular sperm extraction (mTESE) in azoospermic postchemotherapy cancer survivors.

Design

A retrospective cohort study conducted between 2002 and 2017.

Setting

An academic medical center.

Patients

A total of 28 azoospermic postchemotherapy cancer survivors who underwent mTESE.

Interventions

Chemotherapy exposure and mCED calculation.

Main Outcome Measures

The primary outcome was the association between the mCED and sperm retrieval rate using mTESE. The mCED value for each patient's regimen received was estimated using the lowest recommended dosing regimen from the range of recommended doses at the time of administration.

Results

Spermatozoa were successfully retrieved in 11 (39.3%) of the patients. Age at the time of receiving chemotherapy and mCED were significant factors associated with sperm retrieval. An mCED of <4,000 mg/m2 had a higher sperm retrieval rate (10/14, 71.4%) than an mCED of >4,000 mg/m2 (0/8, 0). The hormone levels were not significantly different when comparing patients with and without successful sperm retrieval. Seminoma, nonseminomatous germ cell tumor, and acute lymphoblastic leukemia had favorable sperm retrieval rates-100% (2/2), 66.7% (2/3), and 66.7% (2/3), respectively-although the numbers of patients in each group were small.

Conclusion

Among this cohort of patients with cancer who required chemotherapy regimens, successful sperm retrieval by mTESE was only noted among cancer survivors receiving an mCED of <4,000 mg/m2.

Impact of low- or moderate-risk gonadotoxic chemotherapy prior to testicular tissue freezing on spermatogonia quantity in human (pre)pubertal testicular tissue

STUDY QUESTION

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?

SUMMARY ANSWER

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.

WHAT IS KNOWN ALREADY

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.

STUDY DESIGN, SIZE, DURATION

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.

PARTICIPANTS/MATERIALS, SETTING, METHODS

(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.

MAIN RESULTS AND THE ROLE OF CHANCE

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).

LIMITATIONS, REASONS FOR CAUTION

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.

WIDER IMPLICATIONS OF THE FINDINGS

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.

STUDY FUNDING/COMPETING INTEREST(S)

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.

TRIAL REGISTRATION NUMBER

N/A.

How does chemotherapy treatment damage the prepubertal testis?

Chemotherapy treatment is a mainstay of anticancer regimens, significantly contributing to the recent increase in childhood cancer survival rates. Conventional cancer therapy targets not only malignant but also healthy cells resulting in side effects including infertility. For prepubertal boys, there are currently no fertility preservation strategies in use, although several potential methods are under investigation. Most of the current knowledge in relation to prepubertal gonadotoxicity has been deduced from adult studies; however, the prepubertal testis is relatively quiescent in comparison to the adult. This review provides an overview of research to date in humans and animals describing chemotherapy-induced prepubertal gonadotoxicity, focusing on direct gonadal damage. Testicular damage is dependent upon the agent, dosage, administration schedule and age/pubertal status at time of treatment. The chemotherapy agents investigated so far target the germ cell population activating apoptotic pathways and may also impair Sertoli cell function. Due to use of combined chemotherapy agents for patients, the impact of individual drugs is hard to define, however, use of in vivo and in vitro animal models can overcome this problem. Furthering our understanding of how chemotherapy agents target the prepubertal testis will provide clarity to patients on the gonadotoxicity of different drugs and aid in the development of cytoprotective agents.

Irinotecan metabolite SN38 results in germ cell loss in the testis but not in the ovary of prepubertal mice

STUDY QUESTION

Does the Irinotecan metabolite 7-ethyl-10-hydroxycamptothecan (SN38) damage the gonads of male and female prepubertal mice?

SUMMARY ANSWER

The Irinotecan metabolite SN38 reduces germ cell numbers within the seminiferous tubules of mouse testes at concentrations that are relevant to cancer patients, while in contrast it has little if any effect on the female germ cell population.

WHAT IS KNOWN ALREADY

Little is known about the role of the chemotherapeutic agent Irinotecan on female fertility, with only one article to date reporting menopausal symptoms in perimenopausal women treated with Irinotecan, while no data are available either on adult male fertility or on the impact of Irinotecan on the subsequent fertility of prepubertal cancer patients, female or male.

STUDY DESIGN SIZE, DURATION

Male and female gonads were obtained from postnatal day 5 C57BL/6 mice and exposed in vitro to a range of concentrations of the Irinotecan metabolite SN38: 0.002, 0.01, 0.05, 0.1 or 1 µg ml^–1 for the testis and 0.1, 1, 2.5 or 5 µg ml^–1 for the ovary, with treated gonads compared to control gonads not exposed to SN38. SN38 was dissolved in 0.5% dimethyl sulfoxide, with controls exposed to the same concentration of diluent. The number of testis fragments used for each analysis ranged between 3 and 9 per treatment group, while the number of ovaries used for each analysis ranged between 4 and 12 per treatment group.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Neonatal mouse gonads were developed in vitro, with tissue analysed at the end of the 4–6 day culture period, following immunofluorescence or hematoxylin and eosin staining. Statistical analyses were performed using one-way ANOVA followed by Bonferroni post-hoc test for normally distributed data and Kruskal-Wallis test followed by Dunns post-test for non-parametric data.

MAIN RESULTS AND THE ROLE OF CHANCE

Abnormal testis morphology was observed when tissues were exposed to SN38, with a smaller seminiferous tubule diameter at the highest concentration of SN38 (1 µg ml⁻¹, p < 0.001 versus control) and increased number of Sertoli cell-only tubules at the two highest concentrations of SN38 (0.1 µg ml⁻¹, p < 0.001; 1 µg ml⁻¹, p < 0.0001, both versus control). Within seminiferous tubules, a dose response decrease was observed in both germ cell number (mouse vasa homologue (MVH)-positive cells) and in proliferating cell number (bromodeoxyuridine (BrdU)-positive cells), with significance reached at the two highest concentrations of SN38 (0.1 µg ml⁻¹, p < 0.01 for both; 1 µg ml⁻¹, p < 0.001-MVH, p < 0.01-BrdU; all versus control). No change was seen in protein expression of the apoptotic marker cleaved caspase 3. Double immunofluorescence showed that occasional proliferating germ cells were present in treated testes, even after exposure to the highest drug concentration. When prepubertal ovaries were treated with SN38, no effect was seen on germ cell number, apoptosis or cell proliferation, even after exposure to the highest drug concentrations.

LIMITATIONS REASONS FOR CAUTION

As with any study using in vitro experiments with an experimental animal model, caution is required when extrapolating the present findings to humans. Differences between human and mouse spermatogonial development also need to be considered when assessing the effect of chemotherapeutic exposure. However, the prepubertal testes and ovaries used in the present studies contain germ cell populations that are representative of those found in prepubertal patients, and experimental tissues were exposed to drug concentrations within the range found in patient plasma.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings demonstrate that the prepubertal mouse ovary is relatively insensitive to exposure to the Irinotecan metabolite SN38, while it induces a marked dose-dependent sensitivity in the testicular germ cell population. The study identifies the importance of further investigation to identify the risk of infertility in young male cancer patients treated with Irinotecan.

LARGE SCALE DATA

None.

STUDY FUNDING AND COMPETING INTEREST(S)

Work supported by Medical Research Grant (MRC) grant G1002118 and Children with Cancer UK grant 15-198. The authors declare that there is no conflict of interest that could prejudice the impartiality of the present research.

Systemic cancer therapy: achievements and challenges that lie ahead

In the last half of the century, advances in the systemic therapy of cancer, including chemotherapy, hormonal therapy, targeted therapy, and immunotherapy have been responsible for improvements in cancer related mortality in developed countries even as the population continues to age. Although such advancements have yet to benefit all cancer types, systemic therapies have led to an improvement in overall survival in both the adjuvant and metastatic setting for many cancers. With the pressure to make therapies available as soon as possible, the side-effects of systemic therapies, in particular long-term side-effects are not very well characterized and understood. Increasingly, a number of cancer types are requiring long-term and even lifelong systemic therapy. This is true for both younger and older patients with cancer and has important implications for each subset. Younger patients have an overall greater expected life-span, and as a result may suffer a greater variety of treatment related complications in the long-term, whereas older patients may develop earlier side-effects as a result of their frailty. Because the incidence of cancer in the world will increase over the next several decades and there will be more people living with cancer, it is important to have an understanding of the potential side-effects of new systemic therapies. As an introductory article, in this review series, we begin by describing some of the major advances made in systemic cancer therapy along with some of their known side-effects and we also make an attempt to describe the future of systemic cancer therapy.

Adult survivors of children's cancer and their offspring

BACKGROUND

Although it is anticipated in Japan that the number of long-term survivors of children's cancer will rapidly increase and that they will have children, reports of studies concerning the offspring of such survivors have come mainly from western countries. For this reason, it seems that the results of this study will be important.

METHODS

Ninety-seven survivors of children's cancer, who were diagnosed between 1962 and 1989 and are now older than 20 years old, and their offspring were studied.

RESULTS

Of 97 survivors, 30 have married and 23 survivors or their spouses had been pregnant (33 total pregnancies). Twenty-five babies were born and seven pregnancies ended in spontaneous abortion. The abortion rate was not different from that of the Japanese general population. The birthweights of babies born to survivors tended to be lower than those of control subjects. The proportion of babies with birthweights under 2500 g was significantly greater for babies born to survivors than to the control subjects. None of the 25 babies born had congenital anomalies. Subsequent development of these children has been uneventful with no malignancies after a median follow-up period of 4 years 10 months (range: 10 months to 16 years, 3 months).

CONCLUSIONS

The reproductive activity of children's cancer survivors and the health status of their offspring seem to be satisfactory. However, the sample size of the present study is too small to draw any definite conclusions. Because it is anticipated that the number of long-term survivors of children's cancer will rapidly increase in Japan, it is important to establish an effective system of following up these survivors and their offspring in order to provide them with appropriate suggestions for a better quality of life.

An immunohistochemical study of testicular biopsies in childhood acute lymphoblastic leukemia: reactivity of normal testicular components and leukemic infiltrates

We performed an immunohistochemical analysis of frozen sections from testicular biopsies from 23 children with acute lymphoblastic leukemia. Eleven cases were infiltrated by leukemia. Tumor cells were immunostained by a panel of antibodies that identified CD10, CD43, CD19, CD3, CD7, and MHC class I and II. The immunoreactivity of normal testicular components was also studied. Normal testis showed no CD10 reactivity. Wide variation in the number of stromal macrophages identified by CD11c was found. Transferrin receptor (CD71) was expressed by some stromal macrophages, by seminiferous tubules, and by Leydig cells. B lymphocytes were absent from the testicular stroma but small numbers of T lymphocytes were consistently present. MHC class I and II were expressed by most stromal cells but not by seminiferous tubules.

Fine-needle aspiration biopsy (FNAB) diagnosis of testicular involvement in acute lymphoblastic leukemia in children

A series of 106 fine-needle aspiration biopsy specimens obtained from the testes of children with acute lymphoblastic leukemia was reviewed retrospectively. Involvement by leukemia was seen in 34, there was no evidence of disease in 52, and the cellular sample was inadequate in 20. All aspiration smears, except those with leukemic involvement, showed a variable number of Sertoli cells. Testicular leukemia was diagnosed by the presence of numerous leukemic cells and rare or no Sertoli cells. Fine-needle aspiration biopsy is a simple but effective technique for diagnosing leukemic involvement of the testis in children with acute lymphoblastic leukemia.

Needle biopsy in the diagnosis of testicular leukemia in children

Aggressive chemotherapy in patients with acute lymphoblastic leukemia has resulted in a marked upsurge in patient survival. In the course of their management, testicular biopsy and rebiopsy have an important role. We evaluated the histological findings in 50 sets of open wedge and simultaneous needle core biopsy specimens from 44 testes of children with acute lymphoblastic leukemia to determine the accuracy of the needle biopsy technique in the evaluation of testis involvement in acute lymphoblastic leukemia. We conclude that needle biopsy of the testis in acute lymphoblastic leukemia is highly accurate and correlates well with the conventional open wedge biopsy, and it may have a role in the management of children with acute lymphoblastic leukemia.