Case-control study of congenital anomalies in children of cancer patients

Chemotherapy-induced ovarian damage and protective strategies

More than 9.2 million women worldwide suffer from cancer, and about 5% of them are at reproductive age. Chemotherapy-induced impairment of fertility affects the quality of life of these women. Several chemotherapeutic agents have been proven to cause apoptosis and autophagy by inducing DNA damage and cellular stress. Injuries to the ovarian stroma and micro-vessel network are also considered as pivotal factors resulting in ovarian dysfunction induced by chemotherapeutic agents. Primordial follicle pool over-activation may also be the mechanism inducing damage to the ovarian reserve. Although many studies have explored the mechanisms involved in chemotherapy-induced reproductive toxicity, the exact molecular mechanisms have not been elucidated. It is essential to understand the mechanisms involved in ovarian damage, in order to develop potential protective treatments to preserve fertility. In this article, we reviewed the current knowledge on the mechanism of chemotherapy-induced ovarian damage and possible protective strategies that prevent the ovary from such damages.

Pregnancy in Breast Cancer Survivors

Safety of pregnancy occurring after breast cancer treatment has been studied largely, but it is still debatable. These studies have generally showed that overall and disease-free survival in breast cancer survivors with subsequent pregnancy is not less than those without future pregnancy . Also, breast cancer survivors treated with chemotherapy , radiation therapy, or both had no increased risk of congenital anomalies, single gene disorders, or chromosomal syndromes in their offspring. However, it appears that the incidence of preterm labor, low birth weight, and fetal anomalies is higher in these cases.These issues as well as safe time interval from breast cancer treatment to pregnancy , safe contraceptive method after breast cancer, counseling about pregnancy in survivors, and how to follow up the patient for breast cancer recurrence during pregnancy are discussed in this chapter.

Fertility Preservation for Pediatric and Adolescent Patients With Cancer: Medical and Ethical Considerations

Many cancers presenting in children and adolescents are curable with surgery, chemotherapy, and/or radiotherapy. Potential adverse consequences of treatment include sterility, infertility, or subfertility as a result of gonad removal, damage to germ cells as a result of adjuvant therapy, or damage to the pituitary and hypothalamus or uterus as a result of irradiation. In recent years, treatment of solid tumors and hematologic malignancies has been modified in an attempt to reduce damage to the gonadal axis. Simultaneously, advances in assisted reproductive technology have led to new possibilities for the prevention and treatment of infertility. This clinical report reviews the medical aspects and ethical considerations that arise when considering fertility preservation in pediatric and adolescent patients with cancer.

Ovarian effects of radiation and cytotoxic chemotherapy damage

Oncologic therapy including chemotherapy and radiation can have a significant impact on ovarian function for young women and girls. Poor health outcomes and loss of fertility are major considerations. The effect of radiation and chemotherapy on ovarian function varies depending on patient age, therapy type and dosage, and cancer type. Surgical and medical interventions are available to reduce the morbidity of premature ovarian failure associated with cancer-directed therapy. Fertility preservation is an important consideration, and several options are available for it; therefore, early consultation with a reproductive or oncofertility specialist is an essential part of oncologic care in young women or girls. This chapter will focus on the effects of radiation and chemotherapy on ovarian function and strategies to improve the reproductive care in women with cancer.

Marriage and fertility in long-term survivors of childhood, adolescent and young adult (AYA) high-grade sarcoma

PURPOSE

We investigated the marital status and the presence or absence of children in survivors of childhood, adolescent and young adult (AYA) high-grade sarcoma and examined the influence of these factors on the quality of life (QOL) of these survivors.

METHODS

Thirty-eight survivors of childhood and AYA high-grade sarcoma (18 males, 20 females) participated in a questionnaire survey on marital status and presence or absence of children, as well as on the health-related QOL (HR-QOL), using the Short Form 36 Health Survey. Diagnoses among these survivors were osteosarcoma (28 participants), Ewing's sarcoma (4 participants), synovial sarcoma (4 participants) and others (2 participants).

RESULTS

Of the 18 males who participated in the survey, eight (44.4 %) were married, of whom five (62.5 %) had children. Fifteen (75.0 %) of the 20 females were married, of whom 14 (93.3 %) had children. The proportions of surviving male patients who were married and who had children, respectively, were lower than those of surviving female patients. The proportion of ifosfamide-treated men with children was significantly lower than that of non-ifosfamide-treated men (p = 0.018). With respect to the relationship between marital status and HR-QOL, the scores for the vitality and mental health domains of the SF-36 of survivors who were married were significantly higher than those of unmarried survivors.

CONCLUSIONS

The results of our questionnaire survey reveal that among the male survivors of high-grade sarcoma, the proportions of those who were married and of those with children were lower than those of female survivors, suggesting that strategies providing support for marriage and child-rearing may be necessary for the male survivor group. In the married group, mental QOL was high.

Fertility preservation during cancer treatment: clinical guidelines

The majority of children, adolescents, and young adults diagnosed with cancer today will become long-term survivors. The threat to fertility that cancer treatments pose to young patients cannot be prevented in many cases, and thus research into methods for fertility preservation is developing, aiming at offering cancer patients the ability to have biologically related children in the future. This paper discusses the current status of fertility preservation methods when infertility risks are related to surgical oncologic treatments, radiation therapy, or chemotherapy. Several scientific groups and societies have developed consensus documents and guidelines for fertility preservation. Decisions about fertility and imminent potentially gonadotoxic therapies must be made rapidly. Timely and complete information on the impact of cancer treatment on fertility and fertility preservation options should be presented to all patients when a cancer treatment is planned.

Pregnancy after successful cancer treatment: what needs to be considered?

Over the last decade, advances in oncology led to improved treatment results and increasing numbers of long-term cancer survivors. Fulfilling the desire to have children is important for many patients after cancer treatment. Consequently, oncologists, gynecologists and obstetricians are seeing more patients who wish to conceive after treatment. The necessary prerequisites that should be considered when supporting a planned pregnancy after cancer treatment are discussed in this article. The possible consequences of chemotherapy and radiotherapy on the course of pregnancy and the health of the offspring, as well as the interactions between cancer and pregnancy, are reviewed with the focus on childhood cancer, malignant lymphomas, and breast cancer. Despite chemo- or radiotherapy, neither the teratogenic risk nor the risk of adventitious cancers appears to be increased for the offspring of cancer survivors. However, there is a slightly higher risk of miscarriage after chemotherapy. In case of radiation to the uterus, there is a higher risk of premature birth, intrauterine growth retardation, and increased perinatal mortality. The effect is more pronounced after prepubertal radiation than for postpubertal radiation. The former cancer patient's desire to conceive can nevertheless be supported, given that pregnancy and birth are closely monitored.

Congenital anomalies in the children of cancer survivors: a report from the childhood cancer survivor study

PURPOSE

Children with cancer receive mutagenic treatments, which raises concern about the potential transmissibility of germline damage to their offspring. This question has been inadequately studied to date because of a lack of detailed individual treatment exposure assessment such as gonadal radiation doses.

METHODS

Within the Childhood Cancer Survivor Study, we performed a retrospective cohort analysis of validated cases of congenital anomalies among 4,699 children of 1,128 male and 1,627 female childhood cancer survivors. We quantified chemotherapy with alkylating agents and radiotherapy doses to the testes and ovaries and related these exposures to risk of congenital anomalies using logistic regression.

RESULTS

One hundred twenty-nine children had at least one anomaly (prevalence = 2.7%). For children whose mothers were exposed to radiation or alkylating agents versus neither, the prevalence of anomalies was 3.0% versus 3.5% (P = .51); corresponding figures were 1.9% versus 1.7% (P = .79) for the children of male survivors. Neither ovarian radiation dose (mean, 1.19 Gy; odds ratio [OR] = 0.59; 95% CI, 0.20 to 1.75 for 2.50+ Gy) nor testicular radiation dose (mean, 0.48 Gy; OR = 1.01; 95% CI, 0.36 to 2.83 for 0.50+ Gy) was related to risk of congenital anomalies. Treatment with alkylating agents also was not significantly associated with anomalies in the children of male or female survivors.

CONCLUSION

Our findings offer strong evidence that the children of cancer survivors are not at significantly increased risk for congenital anomalies stemming from their parent's exposure to mutagenic cancer treatments. This information is important for counseling cancer survivors planning to have children.

Options on fertility preservation in female cancer patients

Infertility following treatment of cancer is a quality of survival's recognized issue and efforts should be made to help young cancer patients retaining their fertility potential. Options to preserve fertility in female patients include well established methods such as shielding to reduce radiation damage to reproductive organs, fertility-sparing surgery and emergency in vitro fertilization after controlled ovarian stimulation, aiming at freezing embryos. Transfer of frozen/thawed embryos today is a clinical routine in fertility clinics worldwide and it has been used for over 25 years. Mature oocytes after ovarian stimulation can also be frozen unfertilized, nevertheless overall pregnancy rates after fertilization of frozen-thawn oocytes are still relatively lower than those with embryo freezing. Remaining fertility preservation options are still in development and include the freezing of immature oocytes aiming at later in vitro maturing and fertilizing them and the cryopreservation of ovarian tissue for future retransplantation or for in vitro growth and maturation of follicles, both still experimental.

Pregnancy after breast cancer: case report and review of the literature

Despite breast cancer diagnosis and treatment, women of childbearing age often desire a pregnancy. Since the average age of women giving birth for the first time is increasing, many young patients diagnosed with breast cancer have not started or completed their family planning. Thus, gynecologists and oncologists are confronted more often with the question of childbearing after breast cancer. Current data from retrospective trials do not suggest an increased risk of a recurrence or progress of the disease associated with pregnancy after stage-adjusted treatment. Also, the risk of fetal malformations and damage to the fetus after chemotherapy and/or hormone therapy seems similar to that in the general population. Women who receive chemotherapy are advised to wait at least 6 months before they attempt to conceive. The question whether to become pregnant must be discussed individually with the patient, based on tumor characteristics, stage of the disease and patient's wishes.

Male gonadal toxicity

Cancer treatment with chemotherapy or radiotherapy causes gonadal toxicity in male patients. The endpoint of most concern for future reproductive options is the induction of prolonged azoospermia, which may or may not be reversible. The immediate effects of therapy and its reversibility are most readily observed in post-pubertal patients, but the same antineoplastic regimens given to prepubertal males can induce permanent azoospermia. The probability of permanent azoospermia is related to the specific agents used and their doses. The most damaging are alkylating agents (particularly chlorambucil, procarbazine, cyclophosphamide, melphalan, and busulfan), cisplatin and radiation to the region of the testicles.

Fertility and pregnancy outcome after abdominal irradiation that included or excluded the pelvis in childhood tumor survivors

PURPOSE

To evaluate fertility after abdominal and/or pelvic irradiation in long-term female survivors.

METHODS AND MATERIALS

Puberty and pregnancy outcome were analyzed in female survivors of childhood cancer (aged <18 years) treated with abdominal and/or pelvic radiotherapy (RT) at one of two French centers (Nancy and Lyon) between 1975 and 2004. Data were obtained from medical records and questionnaires sent to the women.

RESULTS

A total of 84 patients who had received abdominal and/or pelvic RT during childhood and were alive and aged more than 18 years at the time of the study made up the study population. Of the 57 female survivors treated with abdominal RT that excluded the pelvis, 52 (91%) progressed normally through puberty and 23 (40%) had at least one recorded pregnancy. Of the 27 patients treated with pelvic RT, only 10 (37%) progressed normally through puberty and 5 (19%) had at least one recorded pregnancy. Twenty-two women (seventeen of whom were treated with pelvic RT) had certain subfertility. A total of 50 births occurred in 28 women, with one baby dying at birth; one miscarriage also occurred. There was a high prevalence of prematurity and low birth weight but not of congenital malformations.

CONCLUSIONS

Fertility can be preserved in patients who undergo abdominal RT that excludes the pelvis, taking into account the other treatments (e.g., chemotherapy with alkylating agents) are taken into account. When RT includes the pelvis, fertility is frequently impaired and women can have difficulty conceiving. Nevertheless, pregnancies can occur in some of these women. The most important factor that endangers a successful pregnancy after RT is the total dose received by the ovaries and uterus. This radiation dose has to be systematically recorded to improve our ability to follow up patients.

Birth outcome in women with previously treated breast cancer--a population-based cohort study from Sweden

BACKGROUND

Data on birth outcome and offspring health after the appearance of breast cancer are limited. The aim of this study was to assess the risk of adverse birth outcomes in women previously treated for invasive breast cancer compared with the general population of mothers.

METHODS AND FINDINGS

Of all 2,870,932 singleton births registered in the Swedish Medical Birth Registry during 1973-2002, 331 first births following breast cancer surgery--with a mean time to pregnancy of 37 mo (range 7-163)--were identified using linkage with the Swedish Cancer Registry. Logistic regression analysis was used. The estimates were adjusted for maternal age, parity, and year of delivery. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate infant health and mortality, delivery complications, the risk of preterm birth, and the rates of instrumental delivery and cesarean section. The large majority of births from women previously treated for breast cancer had no adverse events. However, births by women exposed to breast cancer were associated with an increased risk of delivery complications (OR 1.5, 95% CI 1.2-1.9), cesarean section (OR 1.3, 95% CI 1.0-1.7), very preterm birth (<32 wk) (OR 3.2, 95% CI 1.7-6.0), and low birth weight (<1500 g) (OR 2.9, 95% CI 1.4-5.8). A tendency towards an increased risk of malformations among the infants was seen especially in the later time period (1988-2002) (OR 2.1, 95% CI 1.2-3.7).

CONCLUSIONS

It is reassuring that births overall were without adverse events, but our findings indicate that pregnancies in previously treated breast cancer patients should possibly be regarded as higher risk pregnancies, with consequences for their surveillance and management.

Twenty-year follow-up of osteosarcoma of the extremity treated with adjuvant chemotherapy

We have updated the results of an adjuvant chemotherapy study of 106 patients with osteosarcoma of the extremities published 17 years ago, treated by surgery followed by adjuvant chemotherapy with vincristine (VCR), methotrexate (MTX) and doxorubicin (ADM), between 1980-1983, and followed-up for at least 20 years (20-23 years). In comparison with the results reported 17 years ago with a median follow-up of 38 months (range: 27-66), this updated study showed 24 more deaths, 9 more relapses and 3 second malignancies. Consequently, event-free survival (EFS) and overall survival (OS) are significantly lower compared to the previous study with a 3-year follow up (EFS 38% vs 53%; OS 43.8% vs 67%). We conclude that osteosarcoma patients treated with chemotherapy are at risk of late adverse events. Protracted medical follow-up and long-term updated results are useful to identify, at an early stage, late relapses and late treatment-related complications.

Genetic counselling following paternal therapeutic irradiation

We discuss a patient who received adjuvant radiotherapy for stage I seminoma. He was advised to avoid conception for 6 months following treatment. However, his partner became pregnant only shortly after he completed his radiotherapy (i.e. with sperm that had been irradiated). We estimated the dose received by the remaining testis as 30 cGy. Here, we review the information available to advise patients on the risks to the fetus from paternal preconception irradiation. For the population, a doubling dose for hereditary effects of 1 Gy has recently been reaffirmed (United Nations Scientific Committee on the Effects of Atomic Radiation 2001). However, a range of animal studies suggest conception with postmeiotic sperm carries a greater risk of genetic damage than conception with sperm derived from irradiated stem cells. We have attempted to quantify the risks in this particular case. Lead shielding of the testes may reduce radiation received from the primary beam, but internal scatter still produces a risk. In male patients who are potentially fertile, the best advice remains to delay conception after radiotherapy for as long as 6 months. Our case illustrates the need to reinforce such advice.

Preserving the reproductive potential of men and boys with cancer: current concepts and future prospects

The introduction of ICSI has totally changed the reproductive prospects for boys and men who are treated for cancer. With post-pubertal boys and adult men, semen cryopreservation should be offered to every patient undergoing a cancer treatment since preservation of fertility cannot be guaranteed for an individual patient and treatment may shift to a more sterilizing regimen. In the ICSI era, all semen samples, even those containing only a few motile sperm, should be accepted for cryopreservation. Patients who are azoospermic at the time cancer is diagnosed may be offered testicular sperm extraction and cryopreservation of testicular tissue. With pre-pubertal boys, no prevention of sterility by sperm banking is possible since no active spermatogenesis is present. However, in the next decade, prevention of sterility in childhood cancer survivors will become a major challenge for reproductive medicine. In theory, testicular stem cell banking is the only way of preserving the future fertility of boys undergoing a sterilizing chemotherapy. In animal models, testicular stem cell transplantation has proved to be effective; however, it remains to be shown that this technique is clinically efficient as well, especially when frozen-thawed cells are to be transplanted. Malignancy recurrence prevention is an important prerequisite for any clinical application of testicular stem cell transplantation. Although still at the experimental stage, cryobanking of testicular tissue from pre-pubertal boys may now be considered an acceptable strategy.

European consensus on diagnosis and treatment of germ cell cancer: a report of the European Germ Cell Cancer Consensus Group (EGCCCG)

Germ cell tumour is the most frequent malignant tumour type in young men with a 100% rise in the incidence every 20 years. Despite this, the high sensitivity of germ cell tumours to platinum-based chemotherapy, together with radiation and surgical measures, leads to the high cure rate of > or = 99% in early stages and 90%, 75-80% and 50% in advanced disease with 'good', 'intermediate' and 'poor' prognostic criteria (IGCCCG classification), respectively. The high cure rate in patients with limited metastatic disease allows the reduction of overall treatment load, and therefore less acute and long-term toxicity, e.g. organ sparing surgery for specific cases, reduced dose and treatment volume of irradiation or substitution of node dissection by surveillance or adjuvant chemotherapy according to the presence or absence of vascular invasion. Thus, different treatment options according to prognostic factors including histology, stage and patient factors and possibilities of the treating centre as well may be used to define the treatment strategy which is definitively chosen for an individual patient. However, this strategy of reduction of treatment load as well as the treatment itself require very high expertise of the treating physician with careful management and follow-up and thorough cooperation by the patient as well to maintain the high rate for cure. Treatment decisions must be based on the available evidence which has been the basis for this consensus guideline delivering a clear proposal for diagnostic and treatment measures in each stage of gonadal and extragonadal germ cell tumour and individual clinical situations. Since this guideline is based on the highest evidence level available today, a deviation from these proposals should be a rare and justified exception.

Marriage and fertility in long-term survivors of high grade osteosarcoma

One hundred fifteen patients with high grade osteosarcoma were treated at our hospital between 1976 and 1995. Of these, 45 patients still surviving and disease free for more than 5 years since the conclusion of treatment were enrolled as the subjects. The marriage proportion (number of married persons/number of all persons) and fertility proportion (number of persons having an offspring/number of married persons) of these 45 patients were investigated. The marriage proportion of male patients was 20.8% (5/24), whereas that of female patients was 76.2% (16/21). The marriage proportion in male patients was dramatically lower than that in female patients (p = 0.0003). The marriage proportion in male patients was significantly lower than that in brothers of the patients (p = 0.0223). In female patients, the treatment of osteosarcoma had no influence on marriage, whereas in male patients it had a great influence on marriage. The fertility proportion in married patients was 76.2% (16/21) and that in siblings of the patients was 81.0% (17/21). A total of 18 offspring were born to married patients. These offspring had no birth defects or congenital anomalies. The chemotherapy used in the treatment of osteosarcoma had little influence on the fertility of patients or the health of their offspring.

[Cancer and pregnancy: the medical oncologist's point of view]

Having to start chemotherapy during pregnancy remains a rare event. The decision to proceed with this treatment depends on the drugs used, the time of exposure for the fetus and the gestational age at the time of exposure. The mutagenic potential of the chosen drug has to be known. The risk for the child can then be established without compromising the mother's chances of survival or well-being. This type of situation generally arises in women with breast cancer, leukemia or lymphoma. The first trimester of pregnancy, which corresponds to organogenesis is the most critical period for the fetus. The greatest risk of malformation occurs with anti-metabolite drugs. Chemotherapy can also expose the child to direct in utero toxicity. Myelosuppression is the most common toxic effect, sometimes giving rise to infections and/or fetal hemorrhage. The long-term risks of cancer on the mother's subsequent fertility or the child's intellectual development are not well-known. Such factors must be examined in prospective studies and registered in a specific database.

Fertility issues for young adult survivors of childhood cancer

BACKGROUND

The effects of cancer and its treatment on reproduction and fertility are well-documented, yet knowledge of the psychosocial and behavioral ramifications of these outcomes for young adult survivors of childhood cancer is limited. As a qualitative exploratory study, this work identifies concerns, attitudes, and behaviors that may be associated with childhood cancer survivors' reproductive capacity.

PROCEDURE

As part of a semi-structured interview assessing the impact of cancer on long-term survivors' quality of life, a convenience sample of 32 childhood cancer survivors between the ages of 19-37 and at least five years beyond diagnosis were asked if they had physical limitations as a result of their cancer or treatment, and if having cancer has affected their ability to have children.

RESULTS

These data are organized around two major themes: (1) survivors' reproductive capacity and (2) their attitudes, experiences and concerns about children and parenting. Fifty-nine percent of survivors reported that they are uncertain about their fertility status, and half recall a parent or health care provider ever mentioning potential reproductive problems associated with their past cancer treatment.

CONCLUSIONS

While some survivors profess to know nothing about their risks for infertility, others possess and recall information that influences their personal relationships, their beliefs about having children, and possibly subsequent decisions and behaviors with regard to having children.

Reproductive function after treatment of malignant germ cell ovarian tumors

The outcome and reproductive function were examined among patients with malignant ovarian germ cell tumors treated since 1980. Between 1980 and 2001, fertility-sparing surgery was performed in 26 women, 23 of whom received adjuvant chemotherapy. With a median follow-up of 66.6 months, all patients have been alive, with histological types of 6 immature teratomas, 8 dysgerminomas, 6 yolk sac tumors, and 6 mixed types. Clinical stages were involved of 17 early stage and 9 advanced stage patients. After treatment, 20 women out of 26 recovered menstruation within 6 months. During follow-up, two chemotherapy-untreated and one treated patients experienced 4 conceptions in total. A treated patient conceived but selected artificial termination by affection of chemotherapy. Conservative surgery with adjuvant chemotherapy is the standard approach to treat patients with malignant ovarian germ cell tumors. In these 20 years, we experienced no delivery, so that fertility seems to be seriously affected by treatments.

Fertility in male patients treated with neoadjuvant chemotherapy for osteosarcoma

PURPOSE

To evaluate fertility in male patients with osteosarcoma after chemotherapy including high doses of alkylating agents.

PATIENTS AND METHODS

Postchemotherapy fertility was evaluated in 96 male patients who received chemotherapy at the authors' institution from 1976 to 1996 for localized bone osteosarcoma of the extremities. Four drugs were administrated (doxorubicin, cisplatin, methotrexate, ifosfamide) at different doses according to six different protocols. Eleven patients were prepubertal and 85 were postpubertal at the time of chemotherapy. The median age of these patients at the time of chemotherapy was 17 years (range 10-42), the median age at the time of the interview was 27 years (range 19-53), and the median follow-up from the end of chemotherapy was 9 years (range 4-17).

RESULTS

Of the 96 patients, 26 underwent sperm analysis and 20 showed oligo- or azoospermia. Patients who received high-dose ifosfamide showed a higher incidence of azoospermia. Six patients were normospermic and received no ifosfamide or lower doses of ifosfamide. Eight patients fathered a total of 12 children. No birth defects or congenital anomalies were observed in their offspring.

CONCLUSIONS

The rate of sterility was related to ifosfamide dosage. It appears that pubertal maturation is not affected by chemotherapy. No congenital malformations were seen in the children of the few patients who fathered children.

Do parents of children with congenital malformations have a higher cancer risk? A nationwide study in Denmark

To investigate whether parents of children with congenital malformations more often developed cancer after birth of the child, a population-based case-control study in Denmark was undertaken. By linking the Cancer Registry with the Central Population Registry, we identified 8783 cancer patients having their first child born between 1977 and 1995 before the cancer was diagnosed. Parents of 41 206 firstborn children of a 10% random sample of newborns from the Birth Registry between 1980 and 1995 were identified as controls. We obtained malformation diagnoses of children of cases and controls by linking to the Hospital Discharge Registry. We estimated the association between malformation and cancer by using logistic regression, adjusting for maternal age at birth and sex of child. We found no increased risk of cancer in parents having children with malformations in general, but a higher cancer risk in parents of children born with cleft lip/palate, odds ratio (OR) for all cancer=1.8 (95% confidence interval 1.0-3.2), OR for lymphomas=4.2 (1.3-13.5) and OR for leukaemia=8.1 (2.0-33.7). This association was not restricted to cancer cases diagnosed shortly after birth of the child. Our results suggest a common genetic association between these diseases, but further studies are needed.

Storing reproduction for oncological patients: some points for discussion

Since the introduction of sophisticated techniques of assisted reproduction such as IVF and ICSI, all male patients that undergo a cancer treatment jeopardizing their future fertility status should be offered the opportunity to bank their semen. Only azoospermic semen samples are to be rejected for pre-treatment banking. Patients who became severely oligospermic or azoospermic after chemotherapy but did not bank their semen, are often not allowed to have assisted reproduction because of the concerns about the mutagenic aspects of their treatment. In a small case series (n = 10), we recovered testicular sperm for ICSI in 40% of patients who became azoospermic after chemotherapy. Since, so far, the few clinical data available do no not suggest an increased risk for congenital anomalies in children born from patients obtaining a pregnancy during chemotherapy, the question remains whether the concerns raised about treating patients who became oligozoospermic or azoospermic or even about semen banking during chemotherapy are incontestable.

Minisatellite mutation frequency in human sperm following radiotherapy

Screening pedigrees for inherited minisatellite length changes provides an efficient means of monitoring repeat DNA instability but has given rise to apparently contradictory results regarding the effects of radiation on the human germline. To explore this further in individuals with known radiation doses and to potentially gain information on the timing of mutation induction, we have used an extremely sensitive single molecule approach to quantify the frequencies of mutation at the hypervariable minisatellites B6.7 and CEB1 in the sperm of three seminoma patients following hemipelvic radiotherapy. Scattered radiation doses to the testicles were monitored and pre-treatment sperm DNA was compared with sperm derived from irradiated pre-meiotic, meiotic and post-meiotic cells. We show no evidence for mutation induction in any of the patients and discuss this finding in the context of previous population studies using minisatellites as reporter systems, one of which provided evidence for radiation-induced germline mutation.

Paternal transmission of genetic damage: findings in animals and humans

The concept that mutations can be induced in the male germ-line and result in adverse effects in the offspring has achieved only limited acceptance despite considerable theoretical appeal. This is partly because fetal malformations are generally perceived to be induced solely as a result of maternally mediated events during gestation and partly because the low incidence of the end-points concerned make experimental approaches costly and time-consuming. Nonetheless, a substantial body of work relating to the hypothesis has accumulated in the last 20 years, which has never been reviewed in its entirety. A consideration of the available evidence indicates that preconceptional paternal exposure to mutagens (particularly radiation, cyclophosphamide and ethylnitrosourea) can indeed, under certain conditions, have adverse effects on offspring. The results suggest two principal mechanisms by which such effects may be induced: the induction of germ-line genomic instability or the suppression of germ cell apoptosis.

Pregnancy outcomes in females after treatment for childhood cancer

This Ontario province-wide cohort study was conducted to compare the risk of adverse pregnancy outcomes in female childhood cancer survivors who received abdominal-pelvic radiation and/or chemotherapy with alkylating agents with the risk among those who were treated by non-sterilizing alkylating agents with the risk among those who were treated by non-sterilizing surgery only. Females in Ontario, Canada, diagnosed in 1964-1988 before age 20 with a histologically confirmed malignancy and who had survived for at least 5 years, attained age 18, and were alive at the time of study, were identified through the Ontario Cancer Registry. We ascertained pregnancy outcomes by a telephone-administered questionnaire. Treatment data were abstracted from medical records for 830 subjects 18-49 years of age, the analysis comprised 340 survivors who had one or more pregnancies after treatment. There was no evidence of an increased risk of having a spontaneous abortion or an infant with a birth defect. Survivors receiving abdominal-pelvic radiation were more likely to have a low birth weight infant (odds ratio estimate [OR] = 3.64; 95% confidence interval [CI] = 1.33-9.96), a premature low birth weight infant (OR = 3.29; 95% CI = 0.97-11.1), or an infant who died in the perinatal period (OR = 2.41; 95% CI = 0.50-11.5), compared with those receiving surgery. Risks of perinatal death and having a low birth weight infant increased with dose of radiotherapy directed to the abdomen.

Direct analysis by small-pool PCR of MS205 minisatellite mutation rates in sperm after mutagenic therapies

We have used small-pool PCR to analyse mutation in samples of sperm taken from men after mutagenic therapy. Small-pool PCR uses direct analysis of germline DNA at a highly unstable tandem-repeated "minisatellite" locus to measure rates of length-change mutation in individual sperm samples. The advantages of this approach are that the normal mutation rate is extremely high (about 0.4% per gamete at the locus analysed here), so that relatively small increases in mutation rate can be detectable in individual samples. It is known from work on sperm from untreated individuals that different alleles at this locus have different mutation rates. For this reason, we have analysed the germline mutation rates in sperm samples from two men, in each case comparing a post-treatment sample with a pre-treatment sample from the same individual. We find no evidence for altered mutation in the post-treatment sample, suggesting that the repopulation of the germ-cell compartment after treatment may be subject to stringent mechanisms for the detection and elimination of germ-cell damage.

Pregnancy outcome in long-term survivors of childhood cancer

BACKGROUND

By the year 2010, 1/250 young adults will be long-term survivors of childhood cancer. One of the major concerns is whether they will be able to have healthy children.

PROCEDURE

The literature was reviewed to determine 1) the extent of intrapartum and perinatal complications experienced by survivors or their spouses and 2) the risk of congenital malformations or cancer in their children.

RESULTS AND CONCLUSIONS

Series have reported on pregnancy complications among approximately 400 female survivors and 300 partners of male survivors. An increased incidence of spontaneous abortions, low-birth-weight babies, and neonatal deaths has been described for women with Wilms tumor who had received at least 20 Gy abdominal radiation. Hodgkin disease survivors who had received both radiation and chemotherapy (but not either alone) also appear to be at increased risk of spontaneous abortions. Based on several thousand survivor offspring, there is no overall increased risk of either congenital malformations or childhood cancer. Further studies will define the outcome of offspring of cancer survivors treated in the modern era.

Long-term effects on sexual function and fertility after treatment of testicular cancer

This retrospective study evaluates the types and incidences of sexual disturbances and fertility distress in patients cured from testicular cancer and examines whether there is an effect resulting from different treatment modalities. A self-reported questionnaire was sent to 124 randomly selected patients who were treated at Hanover University Medical School between 1970 and 1993. Ninety-eight patients were included in the study, representing a response rate of 78%. All patients had been in complete remission (CR) for at least 24 months. The median age at diagnosis was 28 years (range 17-44). The median follow-up at the time of study was 12.0 years (range 2.8-25.6). Twenty patients (20%) had been treated for seminomatous and 78 patients (80%) for non-seminomatous germ cell tumours. Treatment included surveillance (7%), primary retroperitoneal lymph node dissection (RPLND) (13%), chemotherapy (CT) (33%), CT + secondary resection of residual retroperitoneal tumour mass (SRRTM) (43%) and infradiaphragmatic radiotherapy (4%). Patients receiving two treatment modalities (CT+SRRTM) reported more frequent an unfulfilled wish for children. Inability of ejaculation was clearly associated with RPLND and SRRTM. Subjective aspects of sexuality, like loss of sexual drive and reduced erectile potential, occurred only in a minority of patients after treatment. No abnormalities were observed concerning the course of pregnancies of partners. In conclusion, sexual dysfunction and infertility are common long-lasting sequelae in testicular cancer survivors affecting approximately 20% of patients. The relative risk for infertility appeared to be elevated for patients treated with the combination of CT+SRRTM. Twenty-one of 40 patients were able to fulfil their wish for children, and no congenital abnormalities were observed in these children.

Long-term genetic and reproductive effects of ionizing radiation and chemotherapeutic agents on cancer patients and their offspring

The continuing search for a cure for cancer has lead to more aggressive therapies as new agents are developed with largely unknown late complications. Standard therapy for the majority of cancers today, following surgery, often consists of combinations of high doses of radiation and multi-drug therapy. Compared with exposures experienced by atomic bomb survivors, cancer survivors have been exposed to higher doses of partial body irradiation and combination chemotherapy over longer periods. Thus, cancer survivors provide a model system with which to evaluate the long-term effects on the human organism of high doses of agents known to damage DNA. Five-year survival after cancer diagnosis is now greater than 56%; more than 5 million Americans are considered cured of cancer. However, the late complications of cancer in long-term survivors has been poorly evaluated, especially in adults, and little is known of the most troubling possibility, that is, that the effects of cancer treatments could be passed on to the next generation. What little we know comes from studies of at most 5,000 survivors of childhood cancer, treated decades ago. So far, results are reassuring that with the means now available, we cannot detect clinical evidence of heritable damage. However, reproductive effects, including infertility, are common consequences of cancer therapy and may represent germ cell damage. We are just in the infancy of studies of germ cell mutagenesis in cancer survivors. The relatively small numbers of survivors, and the few types of exposures studied so far, provide only limited grounds for reassurance. More comprehensive, properly designed, studies of modern new agents are urgently need.

Creating a population-based linked health database: a new resource for health services research

As the availability of both health utilization and outcome information becomes increasingly important to health care researchers and policy makers, the ability to link person-specific health data becomes a critical objective. The integration of population-based administrative health databases has been realized in British Columbia by constructing an historical file of all persons registered with the health care system, and by probabilistically linking various program files to this 'coordinating' file. The linkages have achieved a high rate of success in matching service events to person-specific registration records. This success has allowed research projects to be proposed which would otherwise not have been feasible, and has initiated the development of policies and procedures regarding research access to linked data. These policies and procedures include a framework for addressing the ethical issues surrounding data linkage. With continued attention to confidentiality issues, these linked data present a valuable resource for health services research and planning.

Creating a population-based linked health database: a new resource for health services research

As the availability of both health utilization and outcome information becomes increasingly important to health care researchers and policy makers, the ability to link person-specific health data becomes a critical objective. The integration of population-based administrative health databases has been realized in British Columbia by constructing an historical file of all persons registered with the health care system, and by probabilistically linking various program files to this 'coordinating' file. The linkages have achieved a high rate of success in matching service events to person-specific registration records. This success has allowed research projects to be proposed which would otherwise not have been feasible, and has initiated the development of policies and procedures regarding research access to linked data. These policies and procedures include a framework for addressing the ethical issues surrounding data linkage. With continued attention to confidentiality issues, these linked data present a valuable resource for health services research and planning.

Genetic disease in offspring of long-term survivors of childhood and adolescent cancer

Numerous case series have addressed the concern that cancer therapy may damage germ cells, leading to clinical disease in offspring of survivors. None has documented an increased risk. However, the methodological problems of small series make it difficult to draw firm conclusions regarding the potential of cancer treatments to damage the health of future offspring. We conducted a large interview study of adult survivors of childhood cancer treated before 1976. Genetic disease occurred in 3.4% of 2,198 offspring of survivors, compared with 3.1% of 4,544 offspring of controls (P=.33; not significant); there were no statistically significant differences in the proportion of offspring with cytogenetic syndromes, single-gene defects, or simple malformations. A comparison of survivors treated with potentially mutagenic therapy with survivors not so treated showed no association with sporadic genetic disease (P=.49). The present study provides reassurance that cancer treatment using older protocols does not carry a large risk for genetic disease in offspring conceived many years after treatment. With 80% power to detect an increase as small as 40% in the rate of genetic disease in offspring, this study did not do so. However, we cannot rule out the possibility that new therapeutic agents or specific combinations of agents at high doses may damage germ cells.

Risk of congenital anomalies in children of parents occupationally exposed to low level ionising radiation

OBJECTIVES

To evaluate the risk of having a child with a congenital anomaly in relation to occupational exposure to low level ionising radiation in the pre-conception period.

METHODS

A case-control study based on the Canadian congenital anomalies registry used record linkage techniques to identify congenital anomalies among male and female workers in Canada's largest electric company. Cases were defined as parents of a child with a congenital anomaly born between April 1979 and December 1986 who had a congenital anomaly diagnosed within the first year of life. Controls were an individually matched sample of parents of a liveborn child without an anomaly. Risk of congenital anomaly was assessed in relation to parental exposure to ionising radiation acquired through work within a nuclear generating station of an electric power company. Exposure was assessed according to employment, whether or not the worker was monitored for radiation exposure, and quantitative estimates of radiation dose.

RESULTS

Employment within the electric power industry was not associated with an increased risk of congenital anomalies in the offspring of mothers or fathers. Risk estimates for workers monitored (those who are likely to be exposed to ionising radiation) were 1.75 (95% confidence interval (95% CI) 0.86 to 3.55) for mothers and 0.84 (95% CI 0.68 to 1.05) for fathers. Exposure for fathers before conception, defined cumulatively and for six months before conception, was not associated with increased risk of anomalies in their offspring. There were no significant increases in risk found between type of anomaly and any measure of exposure, although the statistical power in these groups was limited. The study had insufficient numbers to evaluate the effects of ionising radiation in mothers as only three mothers had recorded doses > 0 mSv.

CONCLUSIONS

Overall, workers in a nuclear power industry, and specifically those exposed before conception to low levels of ionising radiation, do not appear to be at an increased risk of having a liveborn child with a congenital anomaly.