Lack of gonadal protection by medroxyprogesterone acetate-induced transient medical castration during chemotherapy for testicular cancer

Advancements in fertility preservation strategies for pediatric male cancer patients: a review of cryopreservation and transplantation of immature testicular tissue

Recently, there has been increasing emphasis on the gonadotoxic effects of cancer therapy in prepubertal boys. As advances in oncology treatments continue to enhance survival rates for prepubertal boys, the need for preserving their functional testicular tissue for future reproduction becomes increasingly vital. Therefore, we explore cutting-edge strategies in fertility preservation, focusing on the cryopreservation and transplantation of immature testicular tissue as a promising avenue. The evolution of cryopreservation techniques, from controlled slow freezing to more recent advancements in vitrification, with an assessment of their strengths and limitations was exhibited. Detailed analysis of cryoprotectants, exposure times, and protocols underscores their impact on immature testicular tissue viability. In transplantation strategy, studies have revealed that the scrotal site may be the preferred location for immature testicular tissue grafting in both autotransplantation and xenotransplantation scenarios. Moreover, the use of biomaterial scaffolds during graft transplantation has shown promise in enhancing graft survival and stimulating spermatogenesis in immature testicular tissue over time. This comprehensive review provides a holistic approach to optimize the preservation strategy of human immature testicular tissue in the future.

Fertility Preservation and Restoration Options for Pre-Pubertal Male Cancer Patients: Current Approaches

Fertility preservation for prepubertal male patients undergoing gonadotoxic therapies, potentially depleting spermatogonial cells, is an expanding necessity, yet most of the feasible options are still in the experimental phase. We present our experience and a summary of current and novel possibilities regarding the different strategies to protect or restore fertility in young male patients, before proceeding with chemotherapy or radiotherapy for malignances or other diseases. Adult oncological patients should always be counselled to cryopreserve the semen before starting treatment, however this approach is not suitable for prepubertal boys, who aren't capable to produce sperm yet. Fortunately, since the survival rate of pediatric cancer patients has skyrocketed in the last decade and it's over 84%, safeguarding their future fertility is becoming a major concern for reproductive medicine. Surgical and medical approaches to personalize treatment or protect the gonads could be a valid first step to take. Testicular tissue autologous grafting or xenografting, and spermatogonial stem cells (SSCs) transplantation, are the main experimental options available, but spermatogenesis in vitro is becoming an intriguing alternative. All of these methods feature both strong and weak prospects. There is also relevant controversy regarding the type of testicular material to preserve and the cryopreservation methods. Since transplanted cells are bound to survive based on SSCs number, many ways to enrich their population in cultures have been proposed, as well as different sites of injection inside the testis. Testicular tissue graft has been experimented on mice, rabbits, rhesus macaques and porcine, allowing the birth of live offspring after performing intracytoplasmic sperm injection (ICSI), however it has never been performed on human males yet. In vitro spermatogenesis remains a mirage, although many steps in the right direction have been performed. The manufacturing of 3D scaffolds and artificial spermatogenetic niche, providing support to stem cells in cultures, seems like the best way to further advance in this field.

Fertility preservation in men: a contemporary overview and a look toward emerging technologies

Cancer and oncologic therapies can have significant adverse effects on male reproductive potential, leaving many men permanently infertile. Fertility preservation has emerged as a key survivorship issue over the past 20 years, and numerous professional societies have published guidelines calling for fertility preservation to become a routine component of oncologic care. Most males with cancer are able to produce a semen specimen for fertility preservation, but numerous other methods of sperm procurement are available for patients who cannot provide a sufficient sample. Despite these options, fertility preservation will remain a challenge for prepubertal boys and men without sperm production. For these patients, experimental and investigational approaches offer the hope that one day they will translate to the clinical arena, offering additional pathways for successful fertility preservation care.

Review : Infertility after chemotherapy: A review of the risks and strategies for prevention

Purpose. Infertility as a late complication of cancer chemotherapy, focusing on specific drug-related ef fects, effects observed in the treatment of certain malignancies, and strategies for prevention is re viewed.

Data Sources. A MEDLINE search of articles from 1966 to present was conducted using the terms infertility, antineoplastics, amenorrhea, azospermia, oogenesis, and spermatogenesis. Additional refer ences were identified using review articles and phar macology textbooks.

Study Selection. All human studies reported in English language were included. Animal studies were included when human data were insufficient or un available.

Data Synthesis. Data on the infertility effects of individual antineoplastic agents are difficult to inter pret for several reasons, including small sample sizes, lack of prechemotherapy fertility assessment, inade quate long-term follow-up, and use of regimens in cluding multiple agents. In general, the incidence and severity of antifertility effects are dependent on the total dosage delivered, duration of therapy, and age at exposure. The alkylating agents have the most signif icant effects on fertility. Fertility outcomes have been reported for several different malignancies, especially in patients cured of Hodgkin's disease and testicular cancer. Information on specific antineoplastic agents and cancers are reviewed. Several methods have been employed to decrease gonadotoxic effects, but none have been effective.

Conclusions. Infertility is a common late com plication of cancer chemotherapy that is receiving increasing attention as the number of cancer survi vors increases. Health care professionals should be aware of infertility risks associated with antineoplastic agents and certain malignancies, and patients should be informed of these risks as treatment decisions are made.

Contemporary and future insights into fertility preservation in male cancer patients

In recent years, survival rates of cancer patients have increased, resulting in a shift of focus from quantity to quality of life. A key aspect of quality of life is fertility potential; patients suffering from iatrogenic infertility often become depressed. Since many cancer therapies—chemotherapy, radiotherapy and/or surgery—and even cancer itself have detrimental effects on the male reproductive system, it is important to preserve fertility before any treatment commences. Currently, the only reliable method of male fertility preservation is sperm banking. For patients who are unable to provide semen samples by the conventional method of masturbation, there are other techniques such as electroejaculation, microsurgical epididymal sperm aspiration and testicular sperm extraction that can be employed. Unfortunately, it is presently impossible to preserve the fertility potential of pre-pubertal patients. Due to the increasing numbers of adolescent cancer patients surviving treatment, extensive research is being conducted into several possible methods such as testicular tissue cryopreservation, xenografting, in vitro gamete maturation and even the creation of artificial gametes. However, in spite of its ease, safety, convenience and many accompanying benefits, sperm banking remains underutilized in cancer patients. There are several barriers involved such as the lack of information and the urgency to begin treatment, but various measures can be put in place to overcome these barriers so that sperm banking can be more widely utilized.

Cryopreservation of testis tissues and in vitro spermatogenesis

Cancer treatments, either chemo‐ or radiotherapy, may cause severe damage to gonads which could lead to the infertility of patients. In post‐pubertal male patients, semen cryopreservation is recommended to preserve the potential to have their own biological children in the future; however, it is not applicable to prepubertals. The preservation of testis tissue which contains spermatogonial stem cells (SSCs) but not sperm would be an alternative measure. The tissues or SSCs have to be transplanted back into patients to obtain sperm; however, this procedure remains experimental, invasive, and is accompanied with the potential risk of re‐implantation of cancer cells. Recently, we developed an organ culture system which supports the spermatogenesis of mice up to sperm formation from SSCs. It was also shown that the tissues could be frozen for later sperm production, which resulted in the generation of offspring. Thus, it could be useful as a clinical application for preserving the reproductive potential of male pediatric cancer patients. The establishment of an optimized cryopreservation method and the development of a culture system for human testis tissue are expected in the future.

Gonadotropin-Releasing Hormone Antagonist (Cetrorelix) Therapy Fails to Protect Nonhuman Primates (Macaca arctoides) From Radiation-Induced Spermatogenic Failure

Treatment of men of reproductive age with radiation or alkylating agents often produces prolonged azoospermia. We previously demonstrated that suppression of testosterone (T) with gonadotropin-releasing hormone (GnRH) analogs restored spermatogenesis following atrophy induced by radiation or chemotherapy in rats. This study tested whether GnRH antagonist therapy could reverse radiation-induced testicular injury in primates with a similar protocol. Adult male stump-tailed macaques were given either 6.7 Gy radiation to the testis alone, 6.7 Gy radiation combined with GnRH-antagonist treatment starting on the day of exposure, or daily injections of the GnRH antagonist Cetrorelix for 3 months alone and were monitored for 18 months. Cetrorelix alone produced a 20-40-week fully reversible suppression of serum T, but although spermatogenic recovery was incomplete, 40%-90% of tubules contained differentiating germ cells. Following radiation alone, testis volumes were reduced to approximately 28% and sperm counts to less than 1% of pretreatment values. A biopsy at 18 months after radiation showed that only 3.0% of seminiferous tubule cross sections had germ cells. In irradiated animals that received GnRH antagonist, testis volumes were reduced to 18% of pretreatment volume, and at 18 months, only 1.9% of seminiferous tubule cross sections contained germ cells. Inhibin B values were reduced to 10% and 3% of pretreatment levels in the radiation-only and the radiation plus GnRH antagonist groups, respectively. Species differences exist in the testicular response to radiation, GnRH antagonist therapy, or both, so that rescue protocols that were successful in rodents might not work in primates.

ICRP publication 118: ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs--threshold doses for tissue reactions in a radiation protection context

This report provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. It was instigated following a recommendation in Publication 103 (ICRP, 2007), and it provides updated estimates of 'practical' threshold doses for tissue injury defined at the level of 1% incidence. Estimates are given for morbidity and mortality endpoints in all organ systems following acute, fractionated, or chronic exposure. The organ systems comprise the haematopoietic, immune, reproductive, circulatory, respiratory, musculoskeletal, endocrine, and nervous systems; the digestive and urinary tracts; the skin; and the eye. Particular attention is paid to circulatory disease and cataracts because of recent evidence of higher incidences of injury than expected after lower doses; hence, threshold doses appear to be lower than previously considered. This is largely because of the increasing incidences with increasing times after exposure. In the context of protection, it is the threshold doses for very long follow-up times that are the most relevant for workers and the public; for example, the atomic bomb survivors with 40-50years of follow-up. Radiotherapy data generally apply for shorter follow-up times because of competing causes of death in cancer patients, and hence the risks of radiation-induced circulatory disease at those earlier times are lower. A variety of biological response modifiers have been used to help reduce late reactions in many tissues. These include antioxidants, radical scavengers, inhibitors of apoptosis, anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, growth factors, and cytokines. In many cases, these give dose modification factors of 1.1-1.2, and in a few cases 1.5-2, indicating the potential for increasing threshold doses in known exposure cases. In contrast, there are agents that enhance radiation responses, notably other cytotoxic agents such as antimetabolites, alkylating agents, anti-angiogenic drugs, and antibiotics, as well as genetic and comorbidity factors. Most tissues show a sparing effect of dose fractionation, so that total doses for a given endpoint are higher if the dose is fractionated rather than when given as a single dose. However, for reactions manifesting very late after low total doses, particularly for cataracts and circulatory disease, it appears that the rate of dose delivery does not modify the low incidence. This implies that the injury in these cases and at these low dose levels is caused by single-hit irreparable-type events. For these two tissues, a threshold dose of 0.5Gy is proposed herein for practical purposes, irrespective of the rate of dose delivery, and future studies may elucidate this judgement further.

Endocrine manipulation in male infertility

Endocrine therapy for male infertility is broadly categorized as specific or nonspecific therapy. Although uncommon, primary endocrine diagnoses in infertile men are amenable to targeted therapy. The efficacy of empiric endocrine therapy for idiopathic male infertility, however, has not been demonstrated conclusively by clinical trials. With better understanding of the underlying pathophysiology of idiopathic male infertility, careful evaluation of endocrine therapy in well-selected treatment groups and well-designed randomized, controlled trials is warranted. Although empiric endocrine therapy for idiopathic male infertility has been largely replaced by assisted reproductive techniques, both treatment modalities could play a role, perhaps as combination therapy.

Hormonal suppression for fertility preservation in males and females

Methods to restore fertility of men and women sterilized by medical treatments and environmental toxicant exposures are under investigation. Rendering spermatogenesis and ovarian follicular development kinetically quiescent by suppression of gonadotropins has been proposed to protect them from damage by cytotoxic therapy. Although the method fails to protect the fertility of male mice and monkeys, gonadotropin and testosterone suppression in rats before or after cytotoxic therapy do enhance the recovery of spermatogenesis. However, the mechanism involves not the induction of quiescence but rather the reversal, by suppression of testosterone, of a block in differentiation of surviving spermatogonia caused by damage to the somatic environment. In men, only one of eight clinical trials was successful in protecting or restoring spermatogenesis after cytotoxic therapy. In women, protection of primordial follicles in several species from damage by cytotoxic agents using GnRH analogs has been claimed; however, only two studies in mice appear convincing. The protection cannot involve the induction of quiescence in the already dormant primordial follicle but may involve direct effects of GnRH analogs or indirect effects of gonadotropin suppression on the whole ovary. Although numerous studies in female patients undergoing chemotherapy indicate that GnRH analogs might be protective of ovarian function, none of the studies showing protection were prospective randomized clinical trials and thus they are inconclusive. Considering interspecies differences and similarities in the gonadal sensitivity to cytotoxic agents and hormones, mechanistic studies are needed to identify the specific beneficial effects of hormonal suppression in select animal models that may be applicable to humans.

Pediatric fertility preservation: is it time to offer testicular tissue cryopreservation?

As the effectiveness of cancer treatments has improved, children diagnosed with cancer can enjoy a longer life free of the disease. However, chemotherapeutic regimens alone or in combination with radiation therapy frequently result in azoospermia or infertility. This paper reviews currently and potentially available methods to maintain fertility in boys undergoing chemotherapy or radiation therapy. Whenever possible, chemotherapeutic agents that are less likely to cause azoospermia, should be considered. Hormonal suppression applied prior to and during chemotherapy may protect future male fertility. Cryopreservation of sperm enables men to reproduce in the future. New techniques, such as in vitro fertilization with intra-cytoplasmic sperm injection offer a more promising future for male cancer sufferers. These techniques however, are not applicable to pre-puberty cancer patients. The use of spermatogonial and embryonic stem cells open new possibilities for boys diagnosed with cancer.

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.

Semen cryopreservation after orchidectomy in men with testicular cancer

OBJECTIVE

To assess the feasibility of semen cryopreservation after orchidectomy in patients with testicular tumour.

PATIENTS AND METHODS

The quality of semen samples was investigated in 36 men with testicular tumour (mean age 31.7 years, range 20-49) who were referred to our infertility centre for semen cryopreservation. For each patient, the number of straws, semen volume, number of spermatozoa, and sperm motility before and after freezing were evaluated.

RESULTS

Fifteen patients (42%) banked sperm before and 21 (58%) after orchidectomy; the delay was >7 days in 19 patients (53%). The mean age, histological diagnosis and tumour stage did not differ significantly whatever the time of cryopreservation. Semen quality did not differ significantly in patients who cryopreserved sperm before or after orchidectomy and there were no significant differences in sperm values whatever the delay before preservation. Semen quality was the same in patients with seminoma or nonseminoma tumour.

CONCLUSION

These findings indicate that spermatogenesis of the contralateral testis is sufficient for successful semen cryopreservation after orchidectomy. Urologists should be encouraged to increase the awareness among oncology teams and patients about the new developments in preserving fertility for patients with cancer.

Protecting spermatogenesis from damage induced by doxorubicin using the luteinizing hormone-releasing hormone agonist leuprorelin: an image analysis study of a rat experimental model

BACKGROUND

This study was performed to investigate the protective effect of a luteinizing hormone-releasing hormone (LHRH) agonist, leuprorelin, against spermatogenetic damage caused by doxorubicin in rats.

METHODS

Sprague-Dawley rats were divided into 4 groups: (1) a control group, (2) a group given LHRH agonist (subcutaneous injections, total dose 9 mg/kg), (3) a group given doxorubicin (intraperitoneal injections, total dose 7.5 mg/kg), and (4) a group given both LHRH agonist (subcutaneous injections, total dose 9 mg/ kg) and doxorubicin (intraperitoneal injections, total dose 7.5 mg/kg). Evaluations were made by measuring body and testicular weights, determining Johnsen's score, and conducting DNA image analysis consisting of DNA content measurement (%1C, %2C, and %4C) by image cytometry.

RESULTS

In the group given doxorubicin, the testicular weight was 1.47 +/- 0.24 mg, Johnsen's score was 4.4 +/- 1.2, and image analysis revealed %1C: 33.8 +/- 9.2, %2C: 43.9 +/- 16.3, and %4C: 5.0 +/- 4.4. In the group given both LHRH agonist and doxorubicin, the testicular weight was 1.32 + 0.23, Johnsen's score was 5.90 + 1.6, and image analysis revealed %1C: 46.9 +/- 15.0, %2C: 28.4 +/- 13.3, and %4C: 8.8 +/- 3.5.

CONCLUSIONS

The significant prophylactic effect (P < 0.05) of the LHRH agonist against doxorubicin-induced spermatogenetic damage was demonstrated by Johnsen's score and image analysis (%1C, %2C, and %4C).

Impact of cyclophosphamide on long-term reduction in sperm count in men treated with combination chemotherapy for Ewing and soft tissue sarcomas

BACKGROUND

Treatment of cancer with multiple-drug chemotherapy regimens or radiation therapy can cause either temporary azoospermia of various durations or permanent azoospermia in young men.

METHODS

To identify which drugs in which doses contribute to long-term or permanent azoospermia, semen analyses were done on patients with Ewing and soft tissue sarcomas before, during, and after treatment with either CYADIC (cyclophosphamide, doxorubicin, and dacarbazine), or CYVADIC (vincristine added to CYADIC). Some patients also received other drugs or radiation therapy.

RESULTS

From pretreatment levels that were similar to those of control subjects, sperm production declined to azoospermia within 4 months of treatment. Sperm production returned in some patients after treatment; 40% of men recovered to normospermic levels by 5 years after treatment. Few patients showed continued recovery of sperm production after that time. The cumulative dose of cyclophosphamide was the most significant determinant of recovery to normospermic levels; approximately 70% of those who had received doses less than 7.5 g/m2 (median, 4.1 g/m2) recovered, but only 10% recovered when doses exceeded 7.5 g/m2.

CONCLUSIONS

Thus, a risk of permanent sterility is associated with the use of the CYADIC and CYVADIC regimens in young men, especially when the cumulative dose of cyclophosphamide is greater than 7.5 mg/m2.