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We can now cure more than 70 per centof all childhood cancers, and this cure

rate approaches 90 per cent for sometumours.1 Enhanced supportive care fordose-intense treatment regimens imposedon a cancer incidence that has been stableover the past 40 years2 is responsible for thissuccess. Where survival is so high, however,further attempts to increase it must bebalanced against the multi-organ toxicitiesto the majority of developing children.Though not necessarily impotent, 15–30 percent of male survivors are rendered infertile,3

either from hypothalamo–pituitary–gonadalexposure to chemoradiation4 or fromdiseases such as Hodgkin’s lymphoma.5

In today’s society, one in six healthy couplesseeks help from reproductive clinics to

conceive,6 with rapid advancements inassisted reproductive technology (ART)having being made in the past two decades.These include cryopreservation of gametesand embryos prior to gonadotoxic cancertherapies to preserve fertility in adults.

IMPACT OF CHILDHOOD CANCERTREATMENT ON MALE FERTILITYSpermatogenesis begins only at puberty. This process requires meiotic division ofdiploid spermatogonia to produce haploidspermatozoa, a process that continuesthereafter throughout adult life.Spermatogenesis requires sufficientintratesticular testosterone productionmaintained by pituitary-derived follicular-stimulating hormone (FSH) and luteinisinghormone (LH) with negative gonadalfeedback from inhibin B (Sertoli cells) andtestosterone (Leydig cells). Both disease- andtreatment-related factors can damage thehypothalamo–pituitary–testicular axis at oneor multiple levels (Figure 1), therebycompromising male reproductive capacity.

ChemotherapyThe rapidly dividing sperm-producingtesticular seminiferous epithelium is highlysusceptible to cytotoxic damage, its extentdetermined by drug type, cumulative drug

In this article, the authors explore the possibilities andparticular developmental and ethical issues surroundingsperm cryopreservation in young boys with cancer, andexamine the unique legal implications of fertilitycounselling in adolescence.

HOONG WEI GAN AND HELEN A. SPOUDEAS

Preserving reproductivecapacity in young boyswith cancer

Hoong Wei Gan, BM BS, BMedSci(Hons),MRCPCH, Specialty Registrar in Paediatrics,Honorary Research Fellow in PaediatricNeuroendocrine Late Effects of ChildhoodCancer; Helen A. Spoudeas, MB BS,DRCOG, FRCP, FRCPCH, MD, Consultant inNeuroendocrine Late Effects of ChildhoodCancer, Honorary Senior Lecturer inPaediatric Endocrinology, University CollegeLondon Hospitals NHS Foundation Trust

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dosage and patient age at exposure. Bycontrast, the testosterone-producing Leydigcells are relatively robust. Consequently,pubertal sexual development may proceednormally (and sometimes early), the only signof gonadotoxicity and future subfertilitybeing small testicular volumes relative to thedegree of virilisation and pubertal stage.

Because cancer treatment protocols aremultidrug regimens, the individual effect ofspecific drug types has proved difficult todetermine accurately. However, most alkylatingagents (eg cyclophosphamide, busulfan,melphalan) and nitrosureas (eg lomustine)demonstrate dose-dependent gonadotoxicity;the UK Children’s Cancer and Leukaemia Group and the British Fertility Society (BFS)have provided helpful ‘guesstimates’ of the‘gonadotoxicity risk’ of current commonchildren’s cancer treatment regimens (Box 1)4,7

in three broad categories – low (<20 per cent),medium (20–80 per cent) and high (>80 percent). Alkylating agents (eg cyclophosphamide)are most likely to cause future subfertility,while protocols for acute lymphoblasticleukaemia (vincristine, methotrexate,cytarabine) are least likely to do so.

RadiotherapyRadiotherapy may affect fertility at more than one level on the hypothalamo–pituitary–testicular axis (see Figure 1). First,the testis is vulnerable to increasing doses ofirradiation, which differentially affect theseminiferous epithelium and Leydig cells(Table 1).8,9 In adults, fractionated doses aslow as 0.1 gray (Gy) may cause temporaryazoospermia, while doses of 2–3Gy are likely to prevent spermatic recovery longterm. Larger doses of 10–12Gy, as used in total body irradiation, damage both Leydig and Sertoli cell function and, if given concurrently with chemotherapy, have additive effects. Hypersecretion of LH can partially compensate for mild Leydig cell dysfunction with near-normal testosterone values (subclinicalhypergonadotrophic hypogonadism), but the long-term impact on bone strengthand cardiac health is unknown.

Cranial irradiation, used in high dose (>40Gy)and primarily for centrally positioned braintumours, may reduce hypothalamo–pituitaryfunction and result in hypogonadotrophichypogonadism.10 In the developing child this

manifests as pubertal delay or arrest,although in the context of pre-existingpituitary disease or tumour these are themore likely causative factors. By contrast,early or precocious puberty is a typicalmanifestation of any cranial injury to theyoung brain (including disease, surgery orirradiation), but its evolution does notpreclude later pubertal arrest and eventualgonadotrophin deficiency affecting both LH–testosterone and FSH–spermatogenicpathways and causing impotence andsubfertility, respectively. Only the former can be treated with testosterone replacement therapy.

DiseaseOccasionally, the disease itself can causetesticular dysfunction. Hodgkin’s disease hasbeen associated with pre-treatmentabnormalities in semen quality even in theabsence of testicular infiltration.5 Thepathogenesis of this phenomenon is poorlyunderstood but is thought to relate todisease-induced inflammatory processes.

CURRENT FERTILITY PRESERVATIONSTRATEGIESIn mature adults, pre-treatment spermcryopreservation has been the mostsuccessful method of fertility preservationsince the 1950s. Spermatozoa are remarkablyresistant to storage and freeze–thawingprocesses, and healthy offspring withoutcongenital anomalies have been reportedfrom sperm stored for up to 28 years.11

Separately stored ‘straws’ of spermatozoacan be thawed as required and used infertility treatments, either directly byintrauterine insemination or byintracytoplasmic sperm injection, a techniqueavailable since 1992 that has markedlyreduced the number of viable spermatozoarequired to single numbers.12

Requesting and obtaining masturbatorysemen samples from older post-pubertalmales is relatively straightforward. However, even ill adults may fail to produce a specimen in this way. For these patients and younger boys unable

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Hypothalamus

LHRH

Pituitary

LH FSH

Testes

Leydig cells(testosterone)

Sertoli cells (inhibin B),seminiferousepithelium

(spermatogenesis)

Chemotherapy and radiotherapy

>0.1–0.2GyRadiotherapy

>20Gy

SurgeryCranial

radiotherapy >35–45Gy

– -

Figure 1. Schematic representation of the hypothalamo–pituitary–testicular axis and potentialsites of disruption secondary to various cancer treatment modalities (red arrows). Thin bluearrows indicate physiological negative feedback mechanisms. LHRH, luteinising hormone-releasing hormone; LH, luteinising hormone; FSH, follicular-stimulating hormone; Gy, gray

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to produce a sample because ofpsychological or sexual immaturity, religious or cultural beliefs, alternatives such as rectal electrostimulation, penilevibratory stimulation, surgical extractionunder general anaesthesia, and evenexperimental techniques such as testiculartissue storage have been considered but not widely practised.

To facilitate service delivery, what remainsunclear is exactly when during pubertalmaturation boys are able spontaneously toejaculate semen containing viable sperm.Spermaturia – the appearance of sperm inthe urine by retrograde ejaculation – hasbeen documented in healthy boys as youngas 11.7 years of age and at a minimumtesticular volume of 4.7ml, with little or no

pubic hair development (Tanner stage P1, G2)and before peak height velocity.13 The agerange for initial spermaturia, however, iswide and up to 17.5 years. Although it hasbeen used as an estimate of true spermarche,there is no documentation of what triggersspermatogenesis, its correlation withpubertal staging and the ability to donatesemen voluntarily, while spermatozoaobtained from urine are less viable and henceunsuitable for cryopreservation.

PIONEERING SERVICE FOR ADOLESCENT BOYS More than 10 years ago, with the support ofcolleagues in child psychiatry, reproductivehealth and haematology/oncologycontributing to the development of age-appropriate information leaflets, awarenesscampaigns and streamlined risk-assessmentsand referrals, we set up a pioneeringendocrine/fertility assessment andcounselling service for adolescents atUniversity College London Hospital. This was targeted at males with cancer aged 12–18 years referred to our tertiary centrefor high-dose therapies.

The repeated three- to four-yearly auditcycles of service in a total of 222 boys over that time have demonstrated asurprisingly consistent and unchangingcounselling rate of some 70 per cent, butwith an appropriately greater prioritisation of those at highest ‘gonadotoxicity risk’ overtime. However, the relative paucity (30.0 percent) of documented pubertal clinicalexaminations persists to date, in spite ofgood biochemical marker measurements(70.3 per cent) and high patient acceptabilityof the counselling process (68.4 per cent).34.2 per cent of the total cohort (and 65.0per cent of those actually attemptingstorage) banked viable sperm produced bymasturbation, the youngest boys being 12.6 years at Tanner stage 3+ and/or with a testicular volume of ≥8ml (Gan HW,Williamson E, Cuddis Z, et al., personalcommunication). Importantly, it washormone parameters of virilisation (testicular volume, plasma LH and

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LOW RISK (<20%)l Acute lymphoblastic leukaemial Wilms’ tumourl Soft tissue sarcoma: stage Il Germ cell tumours: with gonadal preservation and no radiotherapyl Retinoblastomal Brain tumour: surgery only or cranial irradiation <24Gy

MEDIUM RISK (20–80%)l Acute myeloblastic leukaemial Hepatoblastomal Osteosarcomal Ewing’s sarcomal Soft tissue sarcoma: stage II–IIIl Neuroblastomal Non-Hodgkin’s lymphomal Hodgkin’s disease: alternating (‘hybrid’) therapyl Brain tumour: craniospinal radiotherapy or cranial irradiation >24Gy

HIGH RISK (>80%)l Total body irradiationl Chemotherapy conditioning for bone marrow transplantl Localised radiotherapy: pelvic/testicularl Hodgkin’s disease: alkylating agent-based therapyl Soft tissue sarcoma: metastatic/stage IVl Ewing’s sarcoma: metastatic/stage IV

BOX 1. Best estimate guidance for estimating risk of subfertility from varioustreatment modalities based on current regimens used in common childhood andadolescent cancers4,7

0.1–0.2 Transient impairment of spermatogenesis>4 Risk of permanent impairment of spermatogenesis20–30 Leydig cell dysfunction35–45 (cranial) Hypogonadotrophic hypogonadism

Dose of irradiation (Gy) Effects on fertility

Table 1. Effects of increasing doses of irradiation on hypothalamo–pituitary–testiculardysfunction. Note that the impact of total body irradiation is difficult to quantify8,9

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testosterone concentrations), not age per se,that correlated with successful storage, whileparameters of spermatogenesis (plasma FSHconcentration) determined the normality ofsperm concentrations. The role of age cameinto play only as a surrogate marker ofpubertal development and was notindependently predictive of outcome.

Prepubertal boysThere are currently no proven fertilitypreservation techniques for prepubertal boys(testicular volume <4ml). Cryopreservation ofdiploid spermatogonial cells obtained bytesticular biopsy for later post-cure auto-transplantation or in vitro maturation tospermatozoa (as currently debated in youngwomen) is still experimental, withoutsuccessful conceptions, even in animalmodels. Auto-transplantation carries atheoretical risk of reintroducing malignantcells, particularly in haematologicalmalignancies where the testes are potentialsites of metastases. Other prophylactictechniques such as testicular shieldingduring radiotherapy or the administration of gonadotrophin-releasing hormoneanalogues or testosterone to render celldivision quiescent and less susceptible to cytotoxins have limited, if any, practical success.

LEGAL, ETHICAL AND PRACTICALCONSIDERATIONSThe storage and use of haploid gametes and embryos is governed by the HumanFertilisation and Embryology (HFE) Act14 –this mandates personal, not proxy, informedconsent in line with reproductive rights. Thus,unlike for other paediatric procedures – forinstance consenting for an appendicectomy– parents cannot give valid consent on ateenager’s behalf; any minor (under 18 or 16years of age respectively in England andScotland) must be judged intellectually(‘Gillick’) competent to consent withoutcoercion. Written consent to disclosure, HIV,hepatitis B and C testing and the use ofstored samples after death or mentalincapacitation is additionally required at thisdifficult time.

Paradoxically, the legal loophole in whichdiploid prepubertal testicular tissue does not fall under HFE jurisdiction until such time as it becomes haploid leavesprepubertal boys potentially open to harmfrom experimentation – such as surgicalremoval of premeiotic spermatogonia –under the common law of parental consent,even if the sole intent to preserve fertilityappears well intended.

There are few, if any, adolescent-tailoredsperm banking and counselling facilities in the UK, and there is debate as to howadult services might be modified to meettheir specific needs (eg the environment,written information and pornographicmaterial provided). The increased press focus on fertility preservation and NICErecommendations suggest such a servicemight be offered more widely. However,while the young age of this increasingnumber of survivors would indicate a needfor longer-term storage, historically, fewstored samples have ever been used. Thiswould suggest adult survivors either retain or do not ultimately want fertility, but alsothat patients at highest risk of subfertility are those most heavily treated and likely todie from aggressive disease or treatment-related complications.

ADOLESCENT FERTILITY COUNSELLINGSERVICEOncologists may perceive reproduction astoo sensitive and inappropriate a topic tobroach with adolescents already undergoinga complex counselling and consent processfor cancer treatment.15 However, the fewstudies in this area indicate surprisingawareness among adolescents, who in fact welcome discussion and choice – apositive experience at this stage of theirdisease (Box 2).16

Pre-treatment fertility assessmentThe young teenager has unique ethicolegal,physical, psychosexual and intellectual needs that are very different from those ofthe fully mature adult. To be fit for purpose,any adolescent fertility service shouldroutinely, consistently and reliably measureand record pubertal staging and testicularvolumes; this is but one step further than theroutine examination of the testes required toexclude malignant involvement.

Paired with pre-treatment plasma endocrinebiochemistry (LH, FSH, testosterone ± inhibin Bwhere possible), this baseline assessmentshould form the gold standard against whichservice adherence might be judged andaudited. It is vital not only to inform the

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PRE-TREATMENTl Counsel within adolescent-tailored facilities (ideally)l Counsel before commencement of treatmentl Allow sufficient opportunity to bank samples before treatmentl Clinical assessment – pubertal stage, testicular volume, best estimate of

subfertility riskl Biochemical assessment – LH, FSH, testosterone, inhibin Bl Gillick competence and informed consent including virology (HIV, hepatitis B

and C)

POST-TREATMENTl Streamlined late effects follow-up (may have other endocrine toxicities)l Encourage post-treatment semen analysis (do not bank before three months)l Contraceptive advicel Testicular self-examination

BOX 2. Summary of main points in the assessment and counselling for fertilitypreservation in adolescent boys

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counselling process and the individualpatient’s chances of producing a viablesperm sample, but also to assess future serial change indicative of gonadotoxicityand/or spermatic recovery with time.

We have found that collecting spermimmediately after commencement ofchemotherapy (even after only six days’exposure) is likely to reduce sample viabilityby >75 per cent, and therefore this practiceshould be avoided. If it is to be successful inthose judged to be at high risk (see Box 1),fertility preservation should be given earlier and higher priority in the cancercounselling process, even to the point ofdelaying cancer treatment to allow severalattempts where possible.

Post-treatment fertility assessmentThe long-term follow-up of teenage cancersurvivors has not to date emphasised routinefertility assessment, semen analysis and/orsperm banking (against a future relapse) inthose still minors (<18 years) at the end ofcancer therapy.

However, counselling young boys andsupporting them to donate interval post-treatment semen samples, togetherwith routine pubertal and biochemicalassessment, would provide the data neededto inform future age-appropriate servicesand sperm storage facilities based on thetrue gonadotoxicity (and time to recovery) of different cancer treatment regimens andtheir clinical correlates.

This would concur with the 2003 BFSconsensus recommendation that wheresperm was not cryopreserved beforetreatment, a further opportunity at leastthree months from the end of treatment (to reduce the risk of DNA damage) should be offered.7

For the counselling process to be trulycomplete, it should ensure understanding ofthe difference between potency (likely to bepreserved or otherwise easily replaced) andfertility; for those unable or choosing not to

cryopreserve sperm pre-treatment, there is still well-documented potential forrecovery of natural fertility even five yearsafter treatment17 and the consequent need for contraception in all. Testicular self-examination should be encouraged inthe older teenager to monitor for tumourrelapse or secondary malignancies.

CONCLUSIONSAs ART continues to evolve rapidly, fertilitycounselling in adolescence presents a specific and growing challenge. Government-level debate on the future role of the HFE Act would do well to give considerationto the needs of this cohort, who areincreasingly campaigning for protection of their reproductive rights through patient groups such as the Teenage Cancer Trust. Meanwhile, clinicians can be reassured that the large majority of young teenagers welcome the discussion and can exercise appropriate informed choice even in the context of a life-threatening illness. There should thus beample opportunity to discuss optionsavailable to them both before and aftercancer treatment with concurrentlyimproved documentation of consent andclinical examination to make the service truly tailored to the adolescent.

Declaration of interests: none declared.

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