Jeanette Falck Winther

Decreasing Late Mortality Among Five-Year Survivors of Cancer in Childhood and Adolescence: A Population-Based Study in the Nordic Countries

PURPOSE To assess the risk of death in patients who survive more than 5 years after diagnosis of childhood cancer and to evaluate causes of death in fatal cases. PATIENTS AND METHODS This was a population-based study in the five Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden) using data of the nationwide cancer registries and the cause-of-death registries. The study cohort included 13,711 patients who were diagnosed with cancer before the age of 20 years between 1960 and 1989 and who survived at least 5 years from diagnosis. By December 31, 1995, 1,422 patients had died, and death certificates were assessed in 1,402. Standardized mortality ratios (SMRs) for validated causes of death were calculated based on 156,046 patient-years at risk. RESULTS The overall SMR was 10.8 (95% confidence interval [CI], 10.3 to 11.5), mainly due to high excess mortality from the primary cancer. SMR for second cancer was 4.9 (95% CI, 3.9 to 5.9) and was 3.1 (95% CI, 2.8 to 3.5) for noncancer death. The pattern of causes of death varied markedly between different groups of primary cancer diagnoses and was highly dependent on time passed since diagnosis. Overall late mortality was significantly lower in patients treated during the most recent period of time, 1980 to 1989, compared with those treated from 1960 to 1979 (hazard ratio, 0.61; 95% CI, 0.54 to 0.70), and there was no increase in rates of death due to cancer treatment. CONCLUSION Long-term survivors of childhood cancer had an increased mortality rate, mainly dying from primary cancers. However, modern treatments have reduced late cancer mortality without increasing the rate of therapy-related deaths.

Acquisition and persistence of human papillomavirus infection in younger men: a prospective follow-up study among Danish soldiers

No data is yet available on incidence or persistence of human papillomavirus (HPV) infection in men. We enrolled 374 younger male conscripts (18-29 years) in a prospective study, and they were examined twice with an interval of 6 to 8 months. Data collection included a questionnaire and a sample of cells from the penis for HPV detection using PCR. In addition, the presence of Chlamydia trachomatis DNA was assessed in urine samples by means of PCR. The HPV prevalence at the first and second examinations was 33.8% and 31.9%, respectively. The acquisition rate of HPV (overall) during follow-up was 13.8%, and nearly one fourth of the participants were HPV positive at both examinations. Number of sex partners during follow-up was the most important risk factor for acquiring HPV (odds ratio, 17.2; 95% confidence interval, 4.6-64.7, for ≥3 partners versus ≤1 partner). In contrast, acquisition of a new HPV type in initially HPV-positive men was strongly related to having multiple HPV types at enrollment (OR, 4.1; 95% confidence interval, 1.4-12.3). This was also the most important risk factor for HPV persistence together with current smoking and having a high-risk HPV type at enrollment. This is the first study to assess risk factors for acquisition and persistence of HPV. The sexually transmitted nature of the infection is confirmed, and the data point to an important role of having multiple HPV types for persistence.

Lifelong Cancer Incidence in 47 697 Patients Treated for Childhood Cancer in the Nordic Countries

BACKGROUND The pattern of cancer in long-term survivors from childhood cancer has not been investigated comprehensively. METHODS We obtained a cohort of 47,697 children and adolescents aged 0-19 years with cancer as defined by the country-wide cancer registries of Denmark, Finland, Iceland, Norway, and Sweden during 1943-2005. Cohort members were followed through age 79 years for subsequent primary cancers notified to the registries, and the age-specific risk pattern of the survivors was compared with that of the national populations using country and sex standardized incidence ratios (SIRs). We used a multiplicative Poisson regression model to estimate relative risk of cancer for attained age, with adjustment for calendar period and age at diagnosis of primary cancer. We also calculated excess absolute risk (EAR) attributable to status as childhood cancer survivor and determined the cumulative incidence of second primary cancer as a function of attained age for three subcohorts defined by period of treatment for childhood cancer. RESULTS A total of 1180 asynchronous second primary cancers were observed in 1088 persons, yielding an overall SIR of 3.3 (95% confidence interval = 3.1 to 3.5). The relative risk was statistically significantly increased in all age groups, even for cohort members approaching 70 years of age. The EAR for second primary cancer among survivors increased gradually from one additional case per 1000 person-years of observation in early life to six additional cases per 1000 person-years in the age group 60-69 years. For children treated in the prechemotherapy era (1943-1959), the cumulative risk for a second primary cancer reached 18%, 34%, and 48% at ages 60, 70, and 80 years, respectively. The age-specific incidence rates were highest for cohort members treated in the era of intensive, multiple-agent chemotherapy (1975-2005). CONCLUSION Survivors of childhood cancer have a persistent excess risk for a second primary cancer throughout their lives, accompanied by continuous changes in the risk of cancers at specific sites.

Genetic effects of radiotherapy for childhood cancer.

Abstract— Radiation-induced heritable diseases have not been demonstrated in humans and estimates of genetic risks for protection purposes are based on mouse experiments. The most comprehensive epidemiologic study is of the Japanese atomic bomb survivors and their children, which found little evidence for inherited defects attributable to parental radiation. Studies of workers exposed to occupational radiation or of populations exposed to environmental radiation appear too small and exposures too low to convincingly detect inherited genetic damage. In contrast, survivors of childhood cancer form the largest group of people exposed to high doses of ionizing radiation before reproduction and offer unique advantages for studying trans-generation effects. A wide range of gonadal doses are possible, several comparison groups are readily available (including siblings), and there is a strong willingness among cancer survivors to participate in health studies. Cancer patients also have detailed medical records that facilitate both the accurate estimation of gonadal doses and the assessment of potentially confounding factors, such as intercurrent illness, personal and family medical histories, lifestyle characteristics such as tobacco use, and circumstances at delivery. An international study is nearing completion of over 25,000 survivors of childhood cancer in the United States and Denmark who gave birth to or fathered over 6,000 children. Doses to gonads are being reconstructed from radiotherapy records with 46% over 100 mSv and 16% over 1,000 mSv. Adverse pregnancy outcomes being evaluated include major congenital malformations, cytogenetic abnormalities, stillbirths, miscarriages, neonatal deaths, total deaths, leukemia and childhood cancers, altered sex ratio, and birth weight. The main analyses are based on dose-response evaluations. Blood studies of trios (cancer survivor, spouse or partner and offspring) have been initiated to evaluate mechanistic evidence for the transmission of any radiation-induced genetic damage such as minisatellite mutations. Markers of cancer susceptibility such as chromosomal radiosensitivity and genotype profile will also be examined. In the United States series to date, 4,214 children were born to cancer survivors among whom 157 (3.7%) genetic diseases were reported in contrast to 95 (4.1%) reported conditions among 2,339 children born to sibling controls. In the Denmark series the comparable figures were 82 (6.1%) birth defects among 1,345 children of cancer survivors and 211 (5.0%) among 4,225 children of sibling controls. Coupled with prior studies, these preliminary findings, if sustained by ongoing dose-response analyses, provide reassurance that cancer treatments including radiotherapy do not carry much if any risk for inherited genetic disease in offspring conceived after exposure.

Chromosomal Abnormalities among Offspring of Childhood-Cancer Survivors in Denmark: A Population-Based Study

Ionizing radiation and many cancer drugs have the potential to produce germ-cell mutations that might lead to genetic disease in the next generation. In a population-based study, we identified, from records in the Danish Cancer Registry, 4,676 children treated for cancer. Their 6,441 siblings provided a comparison cohort. The results of a search of the Central Population Register identified 2,630 live-born offspring of the survivors and 5,504 live-born offspring of their siblings. The occurrence of abnormal karyotypes diagnosed in these offspring and also in any pregnancies terminated following prenatal diagnosis of a chromosome abnormality was determined from the Danish Cytogenetic Registry. After exclusion of hereditary cases and inclusion of the prenatal cases, after correction for expected viability, the adjusted proportion of live-born children in survivor families with abnormal karyotypes (5.5/2,631.5 [0.21%]) was the same as that among the comparison sibling families (11.8/5,505.8 [0.21%]). There were no significant differences in the occurrence of Down syndrome (relative risk [RR]=1.07; 95% CI 0.16-5.47) or Turner syndrome (RR=1.32; 95% CI 0.17-7.96) among the children of cancer survivors, compared with the children of their siblings. These reassuring results are of importance to the survivors, to their families, and to genetic counselors.

Cancer in siblings of children with cancer in the Nordic countries: a population-based cohort study

BACKGROUND In some rare inherited disorders such as Li-Fraumeni syndrome, relatives of children with cancer are at increased risk of cancer. We aimed to assess relations between childhood cancer and sibling risk, and evaluate the influence of recessive conditions in cancer causation. METHODS We did a population-based cohort study in the Nordic countries of 42277 siblings of 25605 children with cancer. Children with cancer were identified from records in the five Nordic cancer registries, and their siblings from nationwide population registries. Cancers in siblings were documented through record linkage with cancer registries and compared with national incidence rates. We also assessed cancer incidence in parents to identify familial cancer syndromes. FINDINGS 284.2 cancers were expected in siblings, whereas 353 were diagnosed (standardised incidence ratio 1.24 95% CI 1.12-1.38). Risk ratios for siblings were highest in the first decade of life (2.59, 1.89-3.46). We excluded 56 families with genetic syndromes linked to cancer, which reduced this ratio from 1.7 to 1.0 (0.7-1.3) for siblings younger than 20 years, and from 1.3 to 1.0 (0.8-1.3) for those aged 20-29 years. We found no new patterns of familial cancer that indicated inherited susceptibility, or evidence that recessive conditions might contribute to cancers not explained by syndromes. 40% of cancers in siblings that occurred before age 20 years could be attributed to known genetic factors, whereas 60% remained unexplained. INTERPRETATION Apart from rare cancer syndromes, paediatric cancer is not an indicator of increased cancer risk in siblings.

Genetic disease in the children of Danish survivors of childhood and adolescent cancer.

PURPOSE Preconception radiation and chemotherapy have the potential to produce germ cell mutations leading to genetic disease in the next generation. Dose-response relationships were evaluated between cancer treatments and untoward pregnancy outcomes. PATIENTS AND METHODS A case-cohort study was conducted involving 472 Danish survivors of childhood and adolescent cancer and their 1,037 pregnancies. Adverse outcomes included 159 congenital malformations, six chromosomal abnormalities, seven stillbirths, and nine neonatal deaths. Preconception radiation doses to the gonads, uterus, and pituitary gland and administered chemotherapy were quantified based on medical records and related to adverse outcomes using a generalized estimating equation model. RESULTS No statistically significant associations were found between genetic disease in children and parental treatment with alkylating drugs or preconception radiation doses to the testes in male and ovaries in female cancer survivors. Specifically, the risk of genetic disease was similar among the children of irradiated survivors when compared with nonirradiated survivors (relative risk [RR], 1.02; 95% CI, 0.59 to 1.44; P = .94). A statistically significant association between abdomino-pelvic irradiation and malformations, stillbirths, and neonatal deaths was not seen in the children of female survivors overall (P = .07) or in the children of mothers receiving high uterine doses (mean, 13.5 Gy; max, 100 Gy; RR, 2.3; 95% CI, 0.95 to 5.56). CONCLUSION Mutagenic chemotherapy and radiotherapy doses to the gonads were not associated with genetic defects in children of cancer survivors. However, larger studies need to be conducted to further explore potential associations between high-dose pelvic irradiation and specific adverse pregnancy outcomes.

Sex ratio among offspring of childhood cancer survivors treated with radiotherapy

It has been postulated that paternal gonadal exposure would increase the sex ratio by inducing X-chromosomal dominant lethals but that maternal gonadal exposure would decrease the sex ratio by inducing recessive sex-linked lethals. We therefore evaluated the sex ratio (male-to-female ratio) of children born to survivors of childhood cancers in Denmark. Children with cancer were identified from the Danish Cancer Registry from 1943 to 1996 and their offspring from the Central Population Registry. Radiation treatments were determined from records within the Cancer Registry and gonadal radiation exposures were estimated based on the cancer being treated and the likely proximity of the radiation fields to the gonads. Overall, 1100 survivors of childhood cancer became the parents of 2130 children. The sex ratio for male (0.99) and female (1.00) cancer survivors was similar and did not differ significantly from the Danish population (1.06). Radiotherapy did not influence the sex ratio of the children of either male or female survivors, and there was no evidence for dose-related changes over categories of estimated dose to parental gonads. We saw no consistent association between the sex ratio and the interval between cancer diagnosis of the parent and birth of the child. This nationwide study provides no support for the hypothesis that radiation exposure to the gonads results in an inherited genetic effect that would be manifested by a change in the sex ratio of children born after exposure. It may be, however, that sex ratio alterations are not a good or even a valid indicator of possible genetic effects in humans.

Hospital contact for mental disorders in survivors of childhood cancer and their siblings in Denmark: a population-based cohort study

BACKGROUND Survivors of childhood cancer are known to be at risk for long-term physical and mental effects. However, little is known about how cancers can affect mental health in the siblings of these patients. We aimed to assess the long-term risks of mental disorders in survivors of childhood cancer and their siblings. METHODS Hospital contact for mental disorders was assessed in a population-based cohort of 7085 Danish children treated for cancer by contemporary protocols between 1975 and 2010 and in their 13 105 siblings by use of data from the Danish Psychiatric Central Research Registry. Hazard ratios (HRs) for first hospital contact were calculated using a Cox proportional hazards model. We compared these sibling and survivor cohorts with two population-based cohorts who were not childhood cancer survivors or siblings of survivors. FINDINGS Survivors of childhood cancer were at increased risk of hospital contact for mental disorders, with HRs of 1·50 (95% CI 1·32-1·69) for males and 1·26 (1·10-1·44) for females. Children younger than 10 years at diagnosis had the highest risk, and increased risks were seen in survivors of CNS tumours, haematological malignancies, and solid tumours. Survivors had higher risk of neurodevelopmental, emotional, and behavioural disorders than population-based comparisons and siblings, and male survivors had higher risk for unipolar depression. Overall, siblings had no excess risk for mental disorders. However, our data suggest that siblings who were young at the time of cancer diagnosis of the survivor were at increased risk for mental disorders, whereas those older than 15 years at diagnosis were at a lower risk than the general population. INTERPRETATION Childhood cancer survivors should be followed up for mental late effects, especially those diagnosed in young age. Further, clinicians should also be aware that siblings who were young at the time of cancer diagnosis might be at increased risk for mental health disorders.

Cancer occurrence after cosmetic breast implantation in Denmark

Most studies on cancer incidence after breast implantation have focused on breast cancer, while the risk of cancers at other sites has been less well investigated. We examined cancer incidence among 1,653 women who underwent cosmetic breast implant surgery at private clinics of plastic surgery in Denmark and 1,736 women attending the same clinics for other reasons during the period 1973–1995. Furthermore, we updated previously reported results among 1,114 women who received implants for cosmetic indications at public hospitals. All women were followed for cancer through the Danish Cancer Registry. In comparison with the general female population, the overall standardized incidence ratio (SIR) for cancer among women who received implants in private clinics was 1.65 [95% confidence interval (CI) = 1.17–2.27]. This elevated SIR reflected increased incidence ratios for almost all major cancer sites; however, only for non‐melanoma skin cancer was there an excess of more than 2 cases. No significant excess of cancer was observed among women who received implants in public hospitals (SIR = 1.10, 95% CI = 0.76–1.52) or among women attending the private clinics for other problems (SIR = 1.10, 95% CI = 0.78–1.52). The SIRs for breast cancer after breast implantation were 1.1 (95% CI = 0.5–2.2) among private clinic patients and 0.9 (95% CI = 0.4–1.7) among public hospital patients. The overall findings of these 2 implant cohorts and results from other investigations suggest that cancer risk is probably not increased among women receiving cosmetic breast implants. The inconsistent results for private clinics and public hospitals are likely related to selection bias and confounding among the private clinic patients, but our data did not permit exploration of these possibilities. Further research into the determinants of these inconsistencies is warranted. Int. J. Cancer 88:301–306, 2000.