Survival rates for childhood cancer have improved
greatly during the past few decades, and by 2010, one in
715 people in the UK are estimated to be a survivor of
cancer during childhood.1Currently, 75–80% of children
with cancer will be living 5 years after diagnosis.2
Adverse effects of cancer treatment include disorders
of the endocrine system, cardiac and pulmonary
dysfunction, renal and hepatic impairment, secondary
malignant disease, and psychosocial difficulties.
Childhood and adolescence is a period of emotional and
psychological instability, during which issues of sexuality,
including fertility, are of particular importance. Many
treatments for cancer, both in childhood and in later life,
can impair future fertility. Treatment that disrupts fertility
in later life can have a devastating effect, both at the time
of therapy and whenever the patient wishes to start a
family.3Therefore the effect of any proposed therapy is
important to consider, as well as which strategies exist to
protect or restore fertility in later life. A prominent
example is intracytoplasmic sperm injection (figure 1),
which offers the possibility of fatherhood to infertile men
successfully treated for cancer who have had
cryopreserved sperm before treatment.
Gonadal toxicity after cancer treatment
Gonadal damage in young people treated for cancer
can result from either systemic chemotherapy or
radiotherapy affecting the spinal or pelvic area including
whole-body irradiation. Fertility can also be impaired as
a result of cranial irradiation by disruption to the
In male patients, testicular damage can affect the
somatic cells of the testis (Sertoli and Leydig cells) or the
germ cells. Sertoli cells nurture developing germ cells,
and Leydig cells produce testosterone. Cytotoxic
treatment targets rapidly dividing cells and as a result,
spermatogenesis can be disrupted after treatment. The
mechanism of this damage is uncertain, but seems to be
associated with depletion of the proliferating germ-cell
pool by the killing of cells at the stage of differentiating
spermatogonia as well as with stem cells themselves.4
Additionally, those stem spermatogonia that do survive
fail to differentiate any further.5The adult testis actively
produces mature spermatozoa and is therefore very
susceptible to such damage. However, gonadotoxic
treatment at any age can lead to subsequent infertility,6,7
which indicates that the testis is susceptible to such
injury before, during, and after puberty. Evidence shows
that substantial cellular activity takes place in the testis
before puberty, and this activity could be essential for
subsequent healthy, adult testicular function.8
Gametogenesis in the ovary is a very different process to
that in the testis. The human ovary has a fixed number of
primordial follicles, at a maximum at 5 months of gesta-
tional age. These follicles are progressively lost with
increasing age in a biexponential fashion, culminating in
the menopause at about age of 50 years. The rate of oocyte
decline rises at around age 37 years when there are about
25000 primordial oocytes, and precedes the menopause
by 12–14 years when roughly 1000 oocytes remain. The
existence of stem-germ cells in adult ovaries of mice has
recently been suggested,9but not confirmed. Both
chemotherapy and radiotherapy will quicken oocyte
depletion, leading to a premature menopause.10,11Younger
patients have more oocytes, and thus gonadal damage
could seem to be less severe than that in older patients
because the ovary can still support regular ovulatory cycles
even with small numbers of follicles.
Lancet Oncol2005; 6: 209–18
Department of Child Life and
Health (W H B Wallace FRCPCH)
and Department of Obstetrics
Division of Reproductive and
University of Edinburgh,
Edinburgh, UK; and MRC Human
Reproductive Sciences Unit,
Centre for Reproductive
Biology, Edinburgh, UK
Hospital for Sick Children,
Edinburgh EH91LF, UK
http://oncology.thelancet.com Vol 6 April 2005209
W Hamish B Wallace, Richard A Anderson, D Stewart Irvine
Estimates suggest that by 2010, one in 715 people in the UK will have survived cancer during childhood. With
increasing numbers of children cured, attention has focused on their quality of life. We discuss the causes of impaired
fertility after cancer treatment in young people, and outline which patients are at risk and how their gonadal function
should be assessed. With the report of a livebirth after orthotopic transplantation of cryopreserved ovarian tissue and
the continued development of intracytoplasmic sperm injection for men with poor sperm quality, we assess
established and experimental strategies to protect or restore fertility, and discuss the ethical and legal issues that arise.
Fertility preservation for young patients with cancer: who is
at risk and what can be offered?
Figure 1:Intracytoplasmic sperm injection
Effects of radiotherapy
The gonads are sensitive to irradiation, and the resulting
damage depends on the field of treatment, total dose,
and fractionation schedule.12Although fractionation can
improve the therapeutic margin, it might be detrimental
within the gonads because it reduces the time available
In male patients, radiation doses as low as 0·1–1·2 Gy
can impair spermatogenesis, with doses of more than
4 Gy causing permanent damage.13The somatic cells of
the testis are more resistant than the germ cells, and
Leydig-cell dysfunction is not recorded until 20 Gy in
prepubertal boys and 30 Gy in sexually mature men.14
Part loss might be compensated by increased secretion
of luteinising hormone that corrects testosterone
production; therefore many patients will produce
testosterone and develop healthy, secondary sexual
In the paediatric and adolescent age group, testicular
damage takes place with direct irradiation of the testes
(eg, in the management of leukaemia with gonadal
involvement). Radiation doses of 24 Gy are used, which
results in permanent azoospermia.15
irradiation before bone-marrow transplantation will also
affect the testes, and although these effects can be
difficult to elucidate because the treatment is usually
severe disruption of
given concurrently with other therapies, doses of
9–10 Gy have produced gonadal dysfunction.16
In female patients, whole-body, abdominal, or pelvic
irradiation will cause ovarian damage and could also
affect uterine function. As with male individuals, the
degree of impairment depends on the radiation dose,
radiation field, fractionation schedule, and age at the
time of treatment.17–19Depletion of the number of
primordial oocytes after radiotherapy is proportional to
the size of the oocyte pool, as shown by the Faddy-
Gosden model. Therefore, for a given dose of radiation,
the younger patients are at the time of radiotherapy, the
later the onset of premature menopause (figure 2).20
Human oocytes are sensitive to radiation and we have
revised our estimate of the LD50(the lethal dose need to
kill half the total number of oocytes) to be less than
2 Gy.20Therefore, we can predict the age at which
ovarian failure is likely to develop after radiation to a
field that includes the ovary in women treated for cancer.
We have shown that the effective sterilising dose (the
dose of fractionated radiotherapy [Gy] at which
premature ovarian failure takes place immediately after
treatment in 97·5% of patients) falls with increasing age
at treatment. Effective sterilising doses are 20·3 Gy at
birth, 18·4 Gy at 10 years, 16·5 Gy at 20 years, and
14·3 Gy at 30 years. Furthermore, we have been able to
calculate 95% confidence limits for age at premature
ovarian failure for estimated radiation doses to the ovary,
from 1 Gy to the effective sterilising dose and from birth
to 50 years.21
Irradiation affecting the uterus in childhood and
adolescence is associated with a raised incidence of
spontaneous miscarriage and intrauterine growth
retardation.20,22Mechanisms underlying these problems
are probably secondary to reduced elasticity of the
uterine musculature and uterine vascular damage.
CNS tumours are the second most common solid
cancers in childhood. Cranial irradiation is frequently
used in treatment, and although the gonads are not
harmed directly, fertility can be affected by disruption to
the hypothalamic-pituitary-gonadal axis. Patients with
cranial irradiation doses of 35–45 Gy have subsequently
been shown to have deficiencies in plasma gonado-
trophins,23which can result in reduction of sex-steroid
http://oncology.thelancet.com Vol 6 April 2005
Panel 1:Estimated risk of gonadal dysfunction with
Oocyte population (log10)
Oocyte population at
treatment age=10·5 years
13 years for patient
Surviving percentage is
(oocyte population at
treatment age) ?100
at 51 years
Difference in oocyte population after treatment
Faddy-Gosden solution for early menopause
Translation of menopause from 51 to 13 years
Faddy-Gosden model assuming no treatment
Oocyte population after irradiation
Figure 2:Faddy-Gosden model
Use of this model determines the size of the oocyte pool for any age from birth to menopause (estimated at
51years). Graph shows the calculation of an estimated surviving fraction for a patient treated at age 10·5years
with whole-body irradiation (14·4 Gy) who developed ovarian failure at age 13 years, which was 0·56%.
© European Society of Human Reproduction and Embryology. Reproduced by permission of Oxford University Press/Human Reproduction
concentrations and delayed puberty. Hypogonadism
after cranial irradiation has shown to be secondary to the
deficiency of hypothalamic gonadotrophin-releasing
hormone; therefore, exogenous
releasing hormone or gonadotrophins can be used to
Effects of chemotherapy
Cytotoxic chemotherapy can cause gonadal injury, and
the nature and extent of this damage depends on the
drug given, the dose received, and the age and sex of the
patient.25–28Many drugs are gonadotoxic (panel 1),
including procarbazine, cisplatin, and the alkylating
drugs such as cyclophosphamide, melphalan, and
chlorambucil, but all chemotherapeutic drugs could
cause impairment of gonadal function. The relative
contribution of every individual drug can be difficult to
determine because most treatments are given as
As with radiotherapy, the seminiferous epithelium of
the testes is the most sensitive to chemotherapy, and
after patients receive gonadotoxic drugs, they might be
rendered oligospermic or azoospermic. Testosterone
production by Leydig cells is usually unaffected, and
thus development of secondary sexual characteristics is
healthy, although Leydig-cell dysfunction could become
apparent after increased
Hodgkin’s lymphoma is the most common solid
tumour seen in adolescent people. Treatment of this
lymphoma has used procarbazine with alkylating drugs
such as chlorambucil, chlormethine, and cyclophos-
phamide. Although these combinations have resulted in
excellent survival rates, most male patients have
subsequently developed permanent azoospermia.31
Therefore, treatment has been modified to reduce
gonadotoxic effects while maintaining long-term
survival with the ABVD regimen (doxorubicin,
bleomycin, vinblastine, and dacarbazine). However, this
combination includes anthracyclines that are potentially
cardiotoxic. Current treatment of Hodgkin’s lymphoma
for children in the UK includes combination
chemotherapy, with alternating courses of ChlVPP
(chlorambucil, vinblastine, procarbazine, prednisolone)
and ABVD. This regimen is likely to result in
substantially less gonadotoxicity than is treatment based
on alkylating drugs and procarbazine alone.32
Ovarian dysfunction after chemotherapy has been well
described;33premature follicular depletion will result in
early menopause. Byrne and colleagues34followed up
women treated for cancer before the age of 20 years and
recorded that 42% of those treated with radiotherapy and
chemotherapy had reached menopause by the age of
31 years, compared with 5% of controls. Those patients
are also at risk of developing osteoporosis. As with male
patients, procarbazine and alkylating drugs used for
treatment of Hodgkin’s lymphoma are particularly
cumulative doses of
gonadotoxic. Mackie and co-workers25showed that more
than half the female patients in their study had ovarian
dysfunction after ChlVPP
Alternating cycles of ChlVPP and ABVD should reduce
the risk of infertility and premature menopause for
Effects of disease
Although many features of treatment could affect
fertility, disease itself might cause gonadal dysfunction.
Up to 70% of male patients with Hodgkin’s disease
assessed before treatment have impaired semen
quality.35Moreover, semen quality can also be worsened
by fever, anorexia, and pain.
Fertility potential and assessment after cancer
The varied nature of the gonadal insult after
chemotherapy or radiotherapy makes it often difficult to
predict whether a patient about to undergo treatment
will subsequently have impaired fertility. The risk of
subfertility can be classified according to the type of
malignant disease and its associated treatment (panel 2).
For example, conditioning cytotoxic treatment before
http://oncology.thelancet.com Vol 6 April 2005 211
Panel 2:Best assessment of risk of subfertility after current
treatment for common cancers in childhood and
Low risk (?20%)
Acute lymphoblastic leukaemia
Soft-tissue sarcoma: stage I
Germ-cell tumours (with gonadal preservation and no
Brain tumour: surgery only, cranial irradiation ?24 Gy
Acute myeloblastic leukaemia (difficult to quantify)
Ewing’s sarcoma: non-metastatic
Soft-tissue sarcoma: stage II or III
Hodgkin’s disease: alternating treatment
Brain tumour: craniospinal radiotherapy, cranial irradiation
High risk (?80%)
Localised radiotherapy: pelvic or testicular
Chemotherapy conditioning for bone-marrow transplantation
Hodgkin’s disease: treatment with alkylating-drugs
Soft-tissue sarcoma: stage IV (metastatic)
Ewing’s sarcoma: metastatic
chemotherapy and whole-body irradiation has a
substantial risk of gonadotoxic effects,18
treatment of metastatic sarcoma. However, current
treatment for acute lymphoblastic leukaemia, the most
common malignant disease
adolescence, has a low risk of severe gonadotoxic effects.
Treatment protocols for malignant disease are
continually evolving to improve survival and reduce
adverse effects. Although treatment for acute
lymphoblastic leukaemia has intensified over the past
decade, the management of hepatoblastoma, for
example, has become less intensive. Treatments can be
stratified according to risk of relapse, but assessment
of risk can only be estimated and must be continually
updated. Counselling adolescents and their families
thus becomes very difficult. Additionally, patients have
been reported to receive what is thought to be
sterilising treatment and have subsequently shown
recovery of spermatogenesis or ovarian function.36,37
This finding shows the importance of physicians
discussing contraception with patients whose fertility
status is uncertain.
In male patients, semen analysis provides a fair
assessment of spermatogenesis. Moreover, with the
availability of modern techniques of assisted conception,
especially intracytoplasmic sperm injection (figure 1),
men with very severe deficits in semen quality (and even
many of those with non-obstructive azoospermia) can be
helped to achieve parenthood.38In women, amenorrhoea
with premature ovarian failure is unequivocal evidence
of near-complete depletion of ovarian follicles, although
intermittent ovulation and the risk or chance of
conception can subsequently take place.37
The assessment of gonadal function includes clinical
assessment of pubertal progression, biochemical
analysis of plasma gonadotrophins and sex steroids,
semen analysis in male patients, and menstrual history
and ultrasound examination of the uterus and ovaries
in female patients.
Testicular enlargement is the first sign of puberty in
boys, followed by penis enlargement and the
development of pubic hair. As discussed earlier, many
male patients will have preserved Leydig-cell function
after gonadotoxic treatment and therefore will develop
healthy secondary sexual characteristics. However,
their testes could be of reduced size and consistency,
with a loss of tubular space suggestive of diminished
In females, puberty begins with development of the
breast bud, with menarche taking place about 2 years
later. As in males, gonadal volume can be indica-
tiveof gonadal function and is reduced in
Measurement of ovarian volume might allow a
prediction of ovarian reserve (ie, the number of
remaining follicles) and thus reproductive age in
transplantation with high-dose
in childhood and
treated for cancer.40
healthy women, but use of these tests in clinical
practice is not established.41
Biochemical analysis of women who have impaired
fertility after treatment will often show raised
concentrations of follicle-stimulating hormone in the
early follicular phase, despite healthy ovulatory cycles.
Men with mildly compromised Leydig-cell function
could show healthy concentrations of plasma
testosterone, but with slightly increased amounts of
The problem of fertility assessment with these
indices in adolescent people is that interpretation with
respect to future fertility can be difficult. Before
puberty, the hypothalamic-pituitary-gonadal axis is
fairly quiescent, biochemical assessment is unreliable,
and semen analysis and menstrual history is
inappropriate. Therefore, gonadal damage cannot be
detected in childhood at present.
Inhibin B could be a potential marker of
gonadotoxicity in this age group. This glycoprotein is
secreted mainly from Sertoli cells in males and
developing antral follicles in females. It is important in
adult spermatogenesis and folliculogenesis, and in the
feedback regulation of follicle-stimulating-hormone
secretion from the pituitary. Evidence suggests that
gonadotoxic chemotherapy is associated with a
reduction in inhibin B concentrations in male adults,42
presumably indicating lowered sperm production.
However, this association has not been clearly shown
in childhood and adolescence,43and whether inhibin B
will become a factor in fertility assessment of these
patients remains to be seen.
In female patients, much attention has been given to
anti-Mullerian hormone as a potential marker of
ovarian reserve. Anti-Mullerian
glycoprotein that is mainly expressed in the fetal testis,
causing regression of the Mullerian ducts. However,
this hormone is produced by the granulosa cells of
preantral and small antral follicles in females, and
serum amounts of anti-Mullerian hormone correlate
with age and the ovarian follicular reserve.44Indeed,
concentrations of anti-Mullerian hormone are lowered
in females who have survived cancer,40and could
therefore contribute to the assessment of gonadal
function in this group of patients.
hormone is a
Options for fertility preservation
Preservation of fertility is dictated by sexual maturity,
and currently the only established options are
cryopreservation of spermatozoa and embryos (which
need the involvement of a partner).
Semen cryopreservation is an established and successful
technique for male adults, but is especially difficult in
adolescents.45Sperm banking is not universally practised
in paediatric-oncology centres, and very few adolescent-
http://oncology.thelancet.com Vol 6 April 2005
friendly facilities exist. After diagnosis of malignant
disease, treatment is usually started as soon as possible.
At this point, teenagers might be too distressed to
discuss fertility and subsequently unlikely to produce a
semen sample. Discussions should be dealt with
sensitively, and should use appropriate language that is
understood by the patient. However, many individuals
and their families regard open discussion about fertility
beneficial, especially since such interaction emphasises
the future and provides reassurance that curative
treatment is the aim.
The value of considering semen cryopreservation in
adolescent patients has been clearly shown. Semen
samples might be produced by masturbation in boys who
are sufficiently mature, and if this method is not
possible, penile vibratory
electrostimulation under anaesthetic46can be considered.
Alternatively, if spermatogenesis is established, sperm
can be retrieved after testicular or epididymal aspiration.
In the UK, storage of sperm is governed by the Human
Fertilisation and Embryology Act, which means that any
individual storing sperm must be able to understand the
implications of what is proposed, and give valid written
informed consent to storage.
Semen samples produced in adolescence are
frequently of poor quality.47The disease itself will impair
semen quality as discussed earlier, as does psychological
stress. The freeze–thawing process used for cryo-
preservation can then cause further damage, resulting in
impaired sperm motility and damage to chromatin
structure and sperm morphology.48
After cryopreservation, stored spermatozoa can be
used for in-vitro fertilisation. With advances in assisted-
stimulation or rectal
reproduction techniques, especially intracytoplasmic
sperm injection (the injection of a spermatozoan directly
into an oocyte), the problems of low sperm numbers and
poor motility could be circumvented. For patients who
have not yet started puberty, options for fertility
preservation remain entirely experimental at present.
Optimism for these patients in the future lies with
continuing research efforts.
Although the prepubertal testis does not produce
mature spermatozoa, it does contain the diploid stem-
germ cells from which haploid spermatozoa will
ultimately be derived. Therefore, testicular tissue could
be harvested before gonadotoxic cancer therapy and
cryopreserved. After the patient is cured and entering
adulthood, this tissue could be thawed and the stored
germ cells reimplanted into the patient’s own testes, a
procedure known as germ-cell transplantation.49
Alternatively, the stored cells could be matured in vitro
until they can achieve fertilisation by use of
intracytoplasmic sperm injection.
Although the technique of testicular germ-cell
harvest, cryopreservation, and transplantation has
shown to be effective in mice50(figure 3), there are
considerable organisational differences in human
spermatogenesis and whether this approach will be
successful in primates is still unclear.51The best
techniques for obtaining tissue, cryopreservation for
prepubertal tisssue, and an appropriate procedure for
safe and effective returning of germ cells to the testis
still need to be established.
The most important issue to be addressed with
autotransplantation is that tissue is removed from a
patient with cancer (before treatment) to be returned to
http://oncology.thelancet.com Vol 6 April 2005213
Figure 3:Testicular germ-cell transplantation in a busulfan-treated mouse
Harvested and cryopreserved tissue from 9-day-old immature mouse was later thawed and transplanted via efferent ducts into the left testis of an adult sibling, in
whom endogenous spermatogenesis had been ablated by busulfan treatment. Images show (A) transplanted and (B) contralateral untransplanted testis at 74 days’
post-transplantation. Green= proliferating-cell nuclear antigen. Red=smooth-muscle actin (peritubular cells). Magnification ?200.
the patient after they are cured. Therefore, a genuine
risk of reintroducing malignant cells exists, with
potentially fatal consequences. Such effects are unlikely
to take place with malignant diseases such as Hodgkin’s
lymphoma, which is often localised at presentation, but
the risk would be substantial with haematological
cancers,52in which the testes can act as sanctuary sites
for leukaemic cells. Whether this risk can be eliminated
by experimental protocols designed to isolate and purify
testicular stem cells is still unclear.
The technique of maturing stem-germ cells in vitro
could possibly circumvent this risk. Although the
restoration of fertility after in-vitro spermatogenesis has
been reported,53this process included maturation of the
later stages of spermatogenesis rather than stem cells,
and in-vitro maturation of diploid stem cells to haploid
spermatozoa seem unlikely to be technically possible
soon. Alternative approaches that have been considered
include the xenogenic completion of spermatogenesis
after isolation and freezing of spermatogonial cells,54and
the cryopreservation of small pieces of testicular tissue
and use of xenografting to complete spermatogenesis.55
Hormonal manipulation has been investigated as a
potential alternative to these techniques in prepubertal
patients. Because cytotoxic treatment acts mainly on
rapidly dividing cells, germ cells have been postulated to
be less susceptible to cytotoxic effects if hormone
treatments are used to render the testes quiescent.
Although this technique has been successful in rodents56
clinical trials have so far not shown any benefit.57,58
Furthermore, this approach could be ineffective for
children because the proliferation of germ cells in
prepubertal primates might
independent.59Therefore, hormonal manipulation based
on the suppression of this axis is unlikely to be protective
in such patients receiving gonadotoxic treatment.
Studies are currently in progress to identify what factors
regulate spermatogonial proliferation, in the hope of
offering new targets of gonadal protection during
At present there are only two established practices of
fertility preservation in female patients receiving
gonadotoxic cancer therapy.29First, as mentioned earlier,
patients who receive pelvic irradiation might have their
ovaries shielded or removed from the radiation field,60a
procedure known as oophoropexy which can be
undertaken laparoscopically. Although ovarian function
can be preserved with such techniques, radiation-
induced uterine damage will reduce the chances of a
Second, fertility might be preserved by obtaining mature
oocytes before gonadotoxic treatment for in-vitro
fertilisation and subsequent embryo cryopreservation.
This method is only applicable to sexually mature women,
and needs a partner or donor sperm for fertilisation. For
women without a partner, cryopreservation of mature
oocytes is an option, but subsequent pregnancy rates are
substantially lowered because these cells sustain more
damage during the freeze–thaw process than do
embryos.61These techniques are not suitable for most
patients with cancer, because they need a period of ovarian
stimulation that will delay treatment. The technique is
also inappropriate for prepubertal patients, in whom all
fertility preservation strategies remain experimental.
Although mature oocytes cannot be harvested from
prepubertal patients, ovarian tissue consisting of germ
cells can be removed and stored before gonadotoxic
treatment. After patients are cured, this tissue might
either be returned to patients via autotransplantation
or matured in vitro to produce offspring by in-vitro
fertilisation, similar to that proposed for male patients
at this age.
Ovarian tissue can be removed by the use of multiple
biopsy samples from the ovary or by oophorectomy.
Removal of the entire ovary, although strongly
advocated by some researchers in the specialty, is not
recommended for paediatric patients in whom fertility
http://oncology.thelancet.com Vol 6 April 2005
Figure 4:Relative concentration of germ cells in ovary during midfetal life
and young adulthood
(A) Fetal ovary at 21 weeks’ gestation. Ovarian tissue consists mainly of oocytes
at different stages of maturation. Two primordial follicles are clearly shown
(arrows). (B) Ovary from adult aged 23 years. Few primordial follicles are seen
(arrows). Magnification ?400.
outcome is often uncertain. We favour removal of
ovarian cortical strips that can be done laparoscopically,
which produces tissue that is rich in primordial
follicles (figure 4).
Autologous transplantation of this tissue aims to
restore natural fertility and also maintain sex-steroid
production. Cortical strips and biopsies are ideal
because the tissue survives cryopreservation and
undergoes revascularisation on return, although most
primordial follicles are lost. The feasibility of this
process has been shown in sheep62and other mammals,
with both the return of ovarian hormonal activity and
the subsequent production of offspring. After such
success in animals, evidence of ovulation after
orthotopic transplantation in a woman was reported.63
The reports by Oktay and colleagues64
embryonic development after heterotopic trans-
plantation of cryopreserved ovarian tissue) and Donnez
transplantation of cryopreserved ovarian tissue) are
important in showing that ovarian function could
realistically be preserved after sterilising treatment,
although the continuing intermittent ovulation in the
Donnez study raises questions as to whether pregnancy
clearly resulted from the grafted tissue. For prepubertal
girls and most young women, preservation of fertility
remains experimental, and the harvesting and storage
of gonadal tissue before beginning cancer treatment is
the most promising option.
Several issues remain to be clarified, but perhaps the
greatest concern, as with male patients, is the potential
to return malignant cells back to patients after they are
cured. This factor is of particular importance in
patients with haematological malignant disease and
has been shown in a rodent lymphoma.66Oocyte
maturation in vitro, followed by assisted reproduction,
would eliminate this risk. Techniques to mature
oocytes artificially, even from early stages of
development, have yielded some success in mice.67At
present, little is known about the support needed for
this process to take place in human tissue, and the
clinical potential of this technique will need to be
Despite these limitations, several centres have
already removed and stored ovarian cortical strips from
both adolescent and prepubertal patients with cancer
as well as adults. Opportunities for the preservation of
fertility must be taken, but the work should be done
within acceptable guidelines. A working party of the
UK Royal College of Obstetricians and Gynaecologists
published a comprehensive document68
standards of best practice regarding the gathering and
future use of such tissue. In Edinburgh, UK, after
wide-ranging multidisciplinary discussion, we have
agreed on our own selection criteria for patients who
we would regard as candidates for cryopreservation of
ovarian cortical strips (panel 3).
As with male patients, attempts have been made to
protect gonads from cytotoxic damage using analogues
of gonadotrophin-releasing hormone to suppress the
hypothalamic-pituitary-ovarian axis. Preliminary data
from animals suggest that gonadal protection from
alkylating drugs can be achieved,69but no adequately
designed or powered studies address this issue.
Oocyte numbers decline by apoptosis, and inhibition
of this natural process could preserve ovarian function.
Studies in mice have shown that disruption of the gene
encoding acid sphingomyelinase or treatment with
sphingosine-1-phosphate attenuates apoptotic destruc-
tion of primordial fetal oocytes, causing an increase in
numbers of primordial follicles at birth.70Treated
oocytes showed resistance to both chemotherapy-
induced and radiotherapy-induced apoptosis. Although
this approach has enormous potential, the inhibition of
apoptosis in such patients could be associated with
several adverse effects.
Children of cancer survivors
Although these strategies offer real hope of improved
fertility to patients, consideration must be given to
their children. Concerns have been raised that possible
mutagenic effects of cancer treatment could predis-
pose children of patients to congenital abnormalities or
even cancer itself. A large epidemiological study has
failed to show any such link,71apart from those with
familial malignant diseases. However, these children
resulted from natural conception and whether
problems will arise from the use of assisted-
reproduction techniques—whereby natural selec-
tion of healthy sexual reproduction could be
circumvented—is unknown. Sperm from men treated
for cancer in childhood have been shown not to carry
more damaged DNA than did age-matched controls.28
This result provides some reassurance regarding the
http://oncology.thelancet.com Vol 6 April 2005215
Panel 3:Edinburgh criteria for selection for
cryopreservation of ovarian cortical tissue
G Age ?30 years
G No previous chemotherapy or radiotherapy (patients aged
?15 years with previous low-risk chemotherapy should
G Realistic chance of long-term survival
G High risk of treatment-induced immediate ovarian failure
G Informed consent from patient or (in the case of an
incompetent child) from parents
G Negative HIV and hepatitis serology
G No existing children
Criteria are based on multidisciplinary discussion and the working group report of
the Royal College of Obstetricians and Gynaecologists;68these are for guidance
only with every patient assessed individually, and should be updated in view of
emerging evidence and experience.
use of spermatozoa from oligospermic men after
cancer treatment. However, long-term surveillance of
pregnancy outcome and child health remains essential
after the use of assisted-conception technologies in
survivors of cancer.
Ethical and legal issues
The harvesting of gonadal tissue for future use and
other techniques to improve fertility are exciting
prospects that give hope for adolescents with cancer.
Although many scientific and technical issues still
need to be resolved, this technology also raises several
important ethical and legal issues, which should be
addressed before such procedures are used.
When physicians consider options for future fertility
after cancer treatment, any decision must be in the
patient’s best interests. The advantages of any
intervention or of an active decision not to intervene
should outweigh any disadvantages, both in the short
term and long term. Attempts to preserve fertility
should not raise unrealistic expectations, and should
not have undue adverse effects in either the patient or
any subsequent offspring.
Apart from sperm and embryo storage, the
effectiveness of therapeutic intervention is still
unknown. But unless these techniques are considered
now, the opportunity for fertility preservation will be
missed. Fertility preservation should be thought about
in the context of clinical benefit and also of continuing
research. Valid consent to undertake these procedures
is both a legal and an ethical need.
Valid consent must
voluntarily, and given by a competent person. Legal
competence requires that the consenting individual is
able to understand the information given, believes it
applies to them, retains it, and uses it to make an
informed choice. In view of the complexity of the
issues regarding fertility preservation, the anxieties of
patients and their families at diagnosis, and the
restricted time for discussion (due to the urgency of
starting treatment), the validity of such consent could
The issue of valid consent is further complicated
by the age of the patient and their degree of
understanding of the issues being discussed. In the
UK, young people older than 16 years in Scotland and
older than 18 years in England and Wales can consent
to treatment under the Family Law Reform Act (1969).
Otherwise, consent is obtained by proxy or from a
parent or legal guardian. Younger patients could give
valid consent if they show sufficient understanding
and intelligence to make an informed decision, known
as Gillick competence.72With respect to the storage
and future use of gametes, the Human Fertilisation
and Embryology Act specifically excludes consent by
proxy, and parents or legal guardians cannot give
consent on behalf of the child. However, immature
be informed, obtained
germ cells, which include those from prepubertal male
patients and primordial follicles from ovarian cortical
strips, are not gametes and therefore are not under the
responsibility of the Human Fertilisation and
Embryology Authority. These cells can be harvested
with parental consent if the procedure is in the
patient’s best interests. If immature cells were
subsequently matured to produce gametes, this tissue
would then fall under the jurisdiction of the Human
Fertilisation and Embryology Authority.
Consent in situations such as these should be viewed
as a dynamic, continual process that is adapted as new
information becomes available. Indeed, the obtaining
of consent in different stages could alleviate many of
the difficulties discussed earlier.73The first stage of
consent would be for the harvest and storage of the
gonadal tissue. The second stage, at a later date, would
need consent for the use of stored germ-cell material
for both fertilisation and research. Consent needs to be
taken for what should happen to gonadal tissue in case
of the patient’s death; ownership of gonadal tissue
in this situation should not be transferred to
the patient’s relatives.
After extensive, collaborative discussion in a multi-
disciplinary setting, several recommendations have
structured research with centralisation of data and
rapid dissemination of results, a rigorous review of
procedures, and development of the process to obtain
Although many children and adolescents diagnosed
with cancer can now realistically hope for long-term
survival, they must often live with the consequences of
treatment. Infertility is one of the most devastating
adverse effects of cancer treatment in this group of
patients, and methods of protecting or restoring
fertility at an early stage need to be considered. Both
chemotherapy and radiotherapy can impair future
fertility, and treatments for certain cancers can be
sterilising. Although the prediction of fertility after
treatment is very difficult, there is currently much
interest in potential markers of gonadal damage that
could, in the future, be of use in adolescents.
While strategies exist for fertility preservation in
sexually mature patients, very few treatments benefit
younger patients who are at risk of infertility after
treatment. However, several potential therapeutic
interventions are the focus of much research and even
though scientific, technical, legal, and ethical issues
need to be addressed, genuine hope exists for young
survivors of cancer in the future.
Conflict of interest
We declare no conflicts of interest.
We thank Angela Smith for her editorial assistance.
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Search strategy and selection criteria
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