Factors influencing risk-based care of the childhood cancer survivor in the 21st century.

The population of adult survivors of childhood cancer continues to grow as survival rates improve. Although it is well established that these survivors experience various complications and comorbidities related to their malignancy and treatment, this risk is modified by many factors that are not directly linked to their cancer history. Research evaluating the influence of patient-specific demographic and genetic factors, premorbid and comorbid conditions, health behaviors, and aging has identified additional risk factors that influence cancer treatment-related toxicity and possible targets for intervention in this population. Furthermore, although current long-term follow-up guidelines comprehensively address specific therapy-related risks and provide screening recommendations, the risk profile of the population continues to evolve with ongoing modification of treatment strategies and the emergence of novel therapeutics. To address the multifactorial modifiers of cancer treatment-related health risk and evolving treatment approaches, a patient-centered and risk-adapted approach to care that often requires a multidisciplinary team approach, including medical and behavioral providers, is necessary for this population. CA Cancer J Clin 2018;68:133-152. © 2018 American Cancer Society.

Quantitative computed tomography analysis of body composition changes in paediatric patients with acute lymphoblastic leukaemia.

Children with acute lymphoblastic leukaemia (ALL) are at risk for obesity and cardiometabolic diseases. To gain insight into body composition changes among children with ALL, we assessed quantitative computed tomography (QCT) data for specific body compartments (subcutaneous adipose tissue [SAT], visceral adipose tissue [VAT], total adipose tissue [TAT], lean tissue [LT], LT/TAT and VAT/SAT at lumbar vertebrae L1 and L2) at diagnosis and at off-therapy for 189 children with ALL and evaluated associations between body mass index (BMI) Z-score and clinical characteristics. BMI Z-score correlated positively with SAT, VAT and TAT and negatively with LT/TAT and VAT/SAT. At off-therapy, BMI Z-score, SAT, VAT and TAT values were higher than at diagnosis, but LT, LT/TAT and VAT/SAT were lower. Patients aged ≥10 years at diagnosis had higher SAT, VAT and TAT and lower LT and LT/TAT than patients aged 2.0-9.9 years. Female patients had lower LT and LT/TAT than male patients. Black patients had less VAT than White patients. QCT analysis showed increases in adipose tissue and decreases in LT during ALL therapy when BMI Z-scores increased. Early dietary and physical therapy interventions should be considered, particularly for patients at risk for obesity.

Generalizability of "GWAS Hits" in Clinical Populations: Lessons from Childhood Cancer Survivors.

With mounting interest in translating genome-wide association study (GWAS) hits from large meta-analyses (meta-GWAS) in diverse clinical settings, evaluating their generalizability in target populations is crucial. Here, we consider long-term survivors of childhood cancers from the St. Jude Lifetime Cohort Study, and we show the limited generalizability of 1,376 robust SNP associations reported in the general population across 12 complex anthropometric and cardiometabolic phenotypes (n = 2,231; observed-to-expected replication ratio = 0.70, p = 6.2 × 10-8). An examination of five comparable phenotypes in a second independent cohort of survivors from the Childhood Cancer Survivor Study corroborated the overall limited generalizability of meta-GWAS hits to survivors (n = 4,212; observed-to-expected replication ratio = 0.55, p = 5.6 × 10-15). Finally, in direct comparisons of survivor samples against independent equivalently powered general population samples from the UK Biobank, we consistently observed lower meta-GWAS hit replication rates and poorer polygenic risk score predictive performance in survivor samples for multiple phenotypes. As a possible explanation, we found that meta-GWAS hits were less likely to be replicated in survivors who had been exposed to cancer therapies that are associated with phenotype risk. Examination of complementary DNA methylation data in a subset of survivors revealed that treatment-related methylation patterns at genomic sites linked to meta-GWAS hits may disrupt established genetic signals in survivors.

Primary hypothyroidism in childhood cancer survivors: Prevalence, risk factors, and long-term consequences.

BACKGROUND: Data on primary hypothyroidism and its long-term impact on the health, cognition, and quality of life (QOL) of childhood cancer survivors are limited. This study examined the prevalence of and risk factors for primary hypothyroidism and its associations with physical, neurocognitive, and psychosocial outcomes. METHODS: This was a retrospective study with a cross-sectional health outcome analysis of an established cohort comprising 2965 survivors of childhood cancer (52.8% male; median current age, 30.9 years, median time since cancer diagnosis, 22.3 years). Multivariable logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between primary hypothyroidism and cancer-related risk factors, cardiovascular disease risk factors, frailty, neurocognitive and QOL outcomes, social attainment, and subsequent thyroid carcinoma. Associations between serum free thyroxine and thyrotropin levels at assessment and health outcomes were explored. RESULTS: The prevalence of primary hypothyroidism was 14.7% (95% CI, 13.5%-16.0%). It was more likely in females (OR, 1.06; 95% CI, 1.03-1.08), was less likely in non-Whites (OR, 0.96; 95% CI, 0.93-0.99), was associated with thyroid radiotherapy (higher risk at higher doses), and was more common if cancer was diagnosed at an age ≥ 15.0 years versus an age < 5 years (OR, 1.05; 95% CI, 1.01-1.09). Primary hypothyroidism was associated with frailty (OR, 1.54; 95% CI, 1.05-2.26), dyslipidemia (OR, 1.52; 95% CI, 1.14-2.04), impaired physical QOL (OR, 1.66; 95% CI, 1.12-2.48), and having health care insurance (OR, 1.51; 95% CI, 1.07-2.12). CONCLUSIONS: Primary hypothyroidism is common in survivors and is associated with unfavorable physical health and QOL outcomes. The impact of thyroid hormone replacement practices on these outcomes should be investigated further.

Neighborhood effect and obesity in adult survivors of pediatric cancer: A report from the St. Jude lifetime cohort study.

Survivors of childhood cancer are at risk for obesity, a condition potentially modifiable if dietary intake and physical activity are optimized. These health behaviors are likely influenced by neighborhood of residence, a determinant of access to healthy, affordable food and safe and easy exercise opportunities. We examined associations between neighborhood level factors and obesity among survivors in the St. Jude Lifetime cohort and community comparison group members. Persons with residential addresses available for geocoding were eligible for analysis (n = 2,265, mean age 32.5 [SD 9.1] years, 46% female, 85% white). Survivors completed questionnaires regarding individual behaviors; percent body fat was assessed via dual X-ray absorptiometry (obesity: ≥25% males; ≥35% females); neighborhood effect was characterized using census tract of residence (e.g., neighborhood socioeconomic status [SES], rurality). Structural equation modeling was used to determine associations between neighborhood effect, physical activity, diet, smoking, treatment exposures and obesity. Obese survivors (n = 1,420, 62.7%) were more likely to live in neighborhoods with lower SES (RR: 1.23, 95% CI: 1.10-1.38) and rural areas (RR: 1.22, 95% CI: 1.07-1.39) compared to survivors with normal percent body fat. Resource-poor neighborhoods (standardized effect: 0.06, p < 0.001) and cranial radiation (0.16, p < 0.001) had direct effects on percent body fat. Associations between neighborhood of residence and percent body fat were increased (0.01, p = 0.04) among individuals with a poor diet. Neighborhoods where survivors reside as an adult is associated with obesity. Interventions targeting survivors should incorporate strategies that address environmental influences on obesity.

Diabetes mellitus among adult survivors of childhood acute lymphoblastic leukemia: A report from the St. Jude Lifetime Cohort Study.

BACKGROUND: Greater than one-half of children who are treated for acute lymphoblastic leukemia (ALL) develop ≥1 treatment-related medical conditions in their lifetime, many of which are known risk factors for diabetes mellitus. In the current study, the authors evaluated the prevalence and risk factors of diabetes mellitus among clinically assessed adult survivors of childhood ALL METHODS: The authors performed a retrospective evaluation of data from survivors of ALL and community controls who were enrolled in the St. Jude Lifetime Cohort Study between October 1, 2007, and June 30, 2016. Participants were adults with ≥10 years of survival of childhood ALL and community controls who completed clinical and laboratory evaluations. Data for the current analysis were abstracted from medical records. Exposures evaluated herein included chemotherapy and radiation exposures and medical history, including drug-induced diabetes mellitus. RESULTS: Of 1360 eligible adults who were ≥10-year survivors of childhood ALL, a total of 1044 completed the evaluations; these individuals had a mean age of 33.97±9.14 years and 50.86% were male. The 368 controls, 45.65% of whom were male, had a mean age of 35.33±10.21 years. Type 2 diabetes mellitus (T2DM) was found in approximately 7.47% of survivors and 3.80% of controls (odds ratio [OR], 2.07; 95% CI, 1.11-3.87). In adjusted models, among survivors, older age (OR, 1.05 for each additional year; 95% CI, 1.02-1.08), body mass index ≥30 kg/m2 (OR, 7.40; 95% CI, 2.61-20.97), and drug-induced diabetes mellitus occurring during ALL therapy (OR, 4.67; 95% CI, 2.53-8.61) were found to be associated with T2DM. CONCLUSIONS: Adult survivors of childhood ALL are at an increased risk of T2DM. Adult survivors of childhood ALL who are of older age, with an overweight or obese body mass index, and/or who developed drug-induced diabetes mellitus during treatment should be closely monitored for T2DM during long-term follow-up.

Clinically ascertained health outcomes, quality of life, and social attainment among adult survivors of neuroblastoma: A report from the St. Jude Lifetime Cohort.

BACKGROUND: The objective of this study was to characterize chronic disease, health-related quality of life (HRQOL), emotional distress, and social attainment among long-term survivors of neuroblastoma. METHODS: Chronic health conditions among 136 ≥10-year neuroblastoma survivors (median age, 31.9 years; range, 20.2-54.6 years) and 272 community controls (median age, 34.7 years; range, 18.3-59.6 years) were graded with a modified version of the Common Terminology Criteria for Adverse Events (version 4.03). HRQOL and emotional distress were assessed with the Medical Outcomes Study 36-Item Short Form Health Survey and the Brief Symptom Inventory-18. Log-binomial regression and logistic regression were used to compare the prevalence of chronic conditions and the frequency of reduced HRQOL, distress, and social attainment between survivors and controls. The cumulative burden approach was used to estimate multimorbidity. RESULTS: By the age of 35 years, survivors had experienced, on average, 8.5 grade 1 to 5 conditions (95% confidence interval [CI], 7.6-9.3), which was higher than the average for controls (3.3; 95% CI, 2.9-3.7). Compared with controls, survivors had a higher prevalence of any pulmonary (P = .003), auditory (P < .001), gastrointestinal (P < .001), neurological (P = .003), or renal condition (P < .001); were more likely to report poor physical HRQOL (P = .01) and symptoms of anxiety (P = .01) and somatization (P = .01); and were less likely to live independently (P = .01) or marry (P = .01). In analyses limited to survivors, those with 1 or more grade 3 to 5 conditions were more likely to report reduced general health (odds ratio [OR], 6.6; 95% CI, 1.6-26.9), greater bodily pain (OR, 4.2; 95% CI, 1.0-17.0), and unemployment (OR, 3.2; 95% CI, 1.2-8.5). CONCLUSIONS: Because of the high burden of chronic diseases and the associations of these morbidities with reduced HRQOL and social attainment, screening and interventions that provide opportunities to optimize health are important among neuroblastoma survivors.

Estimated number of adult survivors of childhood cancer in United States with cancer-predisposing germline variants.

PURPOSE: To estimate the absolute number of adult survivors of childhood cancer in the U.S. population who carry a pathogenic or likely pathogenic variant in a cancer predisposition gene. METHODS: Using the Surveillance, Epidemiology, and End Results (SEER) Program, we estimated the number of childhood cancer survivors on December 31, 2016 for each childhood cancer diagnosis, multiplied this by the proportion of carriers of pathogenic/likely pathogenic variants in the St. Jude Lifetime Cohort (SJLIFE) study, and projected the resulting number onto the U.S. RESULTS: Based on genome sequence data, 11.8% of 2450 SJLIFE participants carry a pathogenic/likely pathogenic variant in one of 156 cancer predisposition genes. Given this information, we estimate that 21 800 adult survivors of childhood cancer in the United States carry a pathogenic/likely pathogenic variant in one of these genes. The highest estimated absolute number of variant carriers are among survivors of central nervous system tumors (n = 4300), particularly astrocytoma (n = 1800) and other gliomas (n = 1700), acute lymphoblastic leukemia (n = 4300), and retinoblastoma (n = 3500). The most frequently mutated genes are RB1 (n = 3000), NF1 (n = 2300), and BRCA2 (n = 800). CONCLUSION: Given the increasing number of childhood cancer survivors in the United States, clinicians should counsel survivors regarding their potential genetic risk, consider referral for genetic counseling and testing, and, as appropriate, implement syndrome-specific cancer surveillance or risk-reducing measures.

Growth hormone deficiency and neurocognitive function in adult survivors of childhood acute lymphoblastic leukemia.

BACKGROUND: The impact of growth hormone deficiency (GHD) on neurocognitive function is poorly understood in survivors of childhood acute lymphoblastic leukemia (ALL). This study examined the contribution of GHD to functional outcomes while adjusting for cranial radiation therapy (CRT). METHODS: Adult survivors of ALL (N = 571; 49% female; mean age, 37.4 years; age range, 19.4-62.2 years) completed neurocognitive tests and self-reported neurocognitive symptoms, emotional distress, and quality of life. GHD was defined as a previous diagnosis of GHD or a plasma insulin-like growth factor1 level less than -2.0 standard deviations for sex and age at the time of neurocognitive testing. Hypothyroidism, hypogonadism, sex, age at diagnosis, CRT dose, and intrathecal and high-dose intravenous methotrexate were included as covariates in multivariable linear regression models. RESULTS: Of the 571 survivors, 298 (52%) had GHD, and those with GHD received higher doses of CRT (P = .002). Survivors who had GHD, irrespective of prior growth hormone treatment, demonstrated poorer vocabulary (z-score, -0.84 vs -0.61; P = .02), processing speed (z-score, -0.49 vs -0.30; P = .04), cognitive flexibility (z-score, -1.37 vs -0.94; P = .01), and verbal fluency (z-score, -0.74 vs -0.44; P = .001), and they self-reported more neurocognitive problems and poorer quality of life compared with survivors who did not have GHD. Multivariable and mediation models revealed that GHD was associated with small effects on quality of life (general health, P = .01; vitality, P = .01; mental health, P = .01); and CRT dose accounted for the lower neurocognitive outcomes. CONCLUSIONS: Adult survivors of childhood ALL who receive CRT are at risk for GHD, although poor neurocognitive outcomes are determined by CRT dose and not by the presence of GHD.

Physical fitness in survivors of childhood Hodgkin lymphoma: A report from the St. Jude Lifetime Cohort.

BACKGROUND: There are limited data describing fitness and associated health-related quality of life (HRQoL) in survivors of childhood Hodgkin lymphoma (HL). PROCEDURE: Fitness was evaluated among 336 adult survivors of childhood-onset HL treated at St. Jude Children's Research Hospital and 327 controls who never had childhood cancer. The controls were frequency matched on age, sex, and race. Associations were examined between chronic disease and fitness and between fitness and HRQoL using a multivariable linear and logistic regression. RESULTS: Male survivors had lower endurance (6-min walk [6MW] distance 604.4 ± 7.9 m vs 637.0 ± 7.5 m, P < 0.01), and worse neuropathy (modified Total Neuropathy Score [mTNS] 2.7 ± 0.2 vs 1.4 ± 0.2, P < 0.01) compared to controls. Female survivors had lower endurance (6MW distance 564.5 ± 6.9 m vs 590.6 ± 7.0 m, P < 0.01), quadriceps strength (145.7 ± 4.0 vs 163.4 ± 4.0 N·m per kilogram, P < 0.01), and worse neuropathy (mTNS 3.2 ± 0.2 vs 1.4 ± 0.3, P < 0.01) compared to controls. Moderate, severe/disabling, or life-threatening (grades 2-4) neurological conditions were associated with impaired quadriceps strength (odds ratio [OR] 2.94, 99% confidence interval [CI] 1.24-6.96) and impaired endurance (OR 2.96, 99% CI 1.28-6.69). Cardiovascular (OR 2.36, 99% CI 1.00-5.61) and pulmonary (OR 2.78, 99% CI 1.30-5.94) conditions were associated with impaired endurance. Quadriceps strength (ß -6.44 ± 2.01, P < 0.01), endurance (ß -4.63 ± 1.54, P < 0.01), and neuropathy (ß -4.98 ± 1.14, P < 0.01) were associated with a lower physical component summary on the HRQoL. CONCLUSION: Survivors of childhood HL, particularly those with neurological, cardiac, and pulmonary chronic conditions, are at risk for impaired fitness and HRQoL.

Clinical impact of sedentary behaviors in adult survivors of acute lymphoblastic leukemia: A report from the St. Jude Lifetime Cohort study.

BACKGROUND: Sedentary behaviors are associated with poor health outcomes in the general population, but their clinical impact on adult survivors of childhood acute lymphoblastic leukemia (ALL) has not been characterized to date. In the current study, we described the prevalence of sedentary behaviors in survivors of ALL and examined associations between time spent sedentary and body composition and onset of cardiovascular disease (CVD) risk factors. METHODS: Participants' self-reported screen time (eg, television, computer) and activity as measured by accelerometer were used to determine activity time (sedentary, light activity, and moderate or vigorous physical activity). The percentage of time spent in each activity was compared between 331 survivors of ALL and 330 controls. Associations between time sedentary and body composition were evaluated in survivors using linear regression models. Cox proportional hazard models were used to examine the association between time sedentary at baseline and CVD risk factor onset during follow-up. RESULTS: Survivors spent approximately 65% of their time sedentary, 32% in light activity, and 2% in moderate or vigorous physical activity compared with 67% (P = .04), 30% (P<.01), and 3% (P<.01), respectively, in controls. Among survivors, percentage lean body mass decreased by 1.0% ± 0.4% (P = .01) per 10% increase in time sedentary. Survivors who were sedentary ≥60% per day were found to be at an increased risk of high total cholesterol (hazard ratio, 2.52; 95% confidence interval, 1.12-5.64) and any CVD risk factor (hazard ratio, 1.96; 95% confidence interval, 1.16-3.30). CONCLUSIONS: Sedentary behavior is associated with low lean mass and CVD risk factor development and should be limited in survivors of childhood ALL. Cancer 2018;124:1036-43. © 2017 American Cancer Society.

Factors associated with physical activity among adolescent and young adult survivors of early childhood cancer: A report from the childhood cancer survivor study (CCSS).

OBJECTIVE: To evaluate concurrent and longitudinal associations between psychosocial functioning and physical activity in adolescent and young adult survivors of early childhood cancer. METHODS: Adolescent survivors of early childhood cancer (diagnosed before age four) participating in the Childhood Cancer Survivor Study completed the Coping Health and Illness Profile-Adolescent Edition (CHIP-AE; n = 303; mean age at survey: 17.6 years). A subset of these survivors (n = 248) completed a follow-up survey an average of 6.0 years later (range: 4-10). Logistic regression identified associations between psychosocial functioning in adolescence and physical activity levels in adolescence and young adulthood. RESULTS: Survivors reported low physical activity as adolescents (46.1% scored below CHIP-AE cut-point) and young adults (40.8% below Centers for Disease Control guidelines). Poor physical activity during adolescence was associated with female sex (OR = 2.06, 95% CI, 1.18-3.68), parents with less than a college education (OR = 1.91, 95% CI, 1.11-3.32), previous treatment with cranial radiation (OR = 3.35, 95% CI, 1.69-6.88), TV time (OR = 1.77, 95% CI, 1.00-3.14), and limitations of activity due to health or mobility restrictions (OR = 8.28, 95% CI, 2.87-30.34). Poor diet (OR = 1.84, 95% CI, 1.05-3.26) and low self-esteem (OR = 1.80, 95% CI, 0.99-3.31) during adolescence were associated with lower odds of meeting Centers for Disease Control physical activity guidelines in young adulthood. CONCLUSION: These findings provide targets for future interventional studies to improve physical activity in this high-risk population.

Influence of fitness on health status among survivors of acute lymphoblastic leukemia.

INTRODUCTION: We aimed to determine the prevalence of self-reported adverse health status among childhood acute lymphoblastic leukemia (ALL) survivors and to identify associations between components of physical fitness and health status. METHODS: Participants included 365 ALL survivors (mean age at evaluation of 28.6 ± 5.9 years) and 365 age-, sex-, and race-matched community controls. Self-report of poor general health, poor mental health, functional impairments, and activity limitations were used to describe adverse health status. Fitness was evaluated by assessing flexibility, muscular strength and endurance, peak oxygen uptake, and balance. Generalized linear models were used to examine associations between fitness metrics and health status. RESULTS: Survivors were more likely than controls to report poor general health (20.6% vs. 10.4%, risk ratio [RR] = 2.0, 95% confidence intervals [CI] = 1.4-2.9), poor mental health (28.0% vs. 14.5%, RR = 1.9, 95% CI = 1.4-2.6), functional impairments (10.5% vs. 4.1%, RR = 2.5, 95% CI = 1.4-4.6), and activity limitations (29.0% vs. 14.4%, RR = 2.0, 95% CI = 1.5-2.7). Survivors whose balance scores were more than 1.5 standard deviations below the mean of the control population were more likely to report poor general health (RR = 1.7, 95% CI = 1.1-2.8), poor mental health (RR = 1.9, 95% CI = 1.3-2.8), and functional limitations (RR = 2.5, 95% CI = 1.2-56). Survivors with low strength were more likely to report poor general health (RR = 1.8, 95% CI = 1.1-3.1), functional impairments (RR = 4.2, 95% CI = 1.7-10.4), and activity limitations (RR = 1.8, 95% CI = 1.2-2.8). CONCLUSIONS: ALL survivors, particularly those with poor balance and reduced muscular strength, are at increased risk for adverse health status.

Impact of ovarian transposition before pelvic irradiation on ovarian function among long-term survivors of childhood Hodgkin lymphoma: A report from the St. Jude Lifetime Cohort Study.

BACKGROUND: We reviewed the effect of ovarian transposition (OT) on ovarian function among long-term survivors of childhood Hodgkin lymphoma (HL) treated with pelvic radiotherapy. PROCEDURE: Female participants (age 18+ years) with HL in the St. Jude Lifetime Cohort Study (SJLIFE) were clinically evaluated for premature ovarian insufficiency (POI) 10 or more years after pelvic radiotherapy. Reproductive history including age at menopause and pregnancy/live births was available on all patients. RESULTS: Of 127 eligible females with HL, 90 (80%) participated in SJLIFE, including 49 who underwent OT before pelvic radiotherapy. Median age at STLIFE evaluation was 38 years (range 25-60). In a multiple regression adjusted for age at diagnosis, pelvic radiotherapy doses > 1,500 cGy (hazard ratio [HR] = 25.2, 95% confidence interval [CI] = 3.1-207.3; P = 0.0027) and cumulative cyclophosphamide equivalent doses of alkylating agents > 12,000 mg/m2 (HR = 11.2, 95% CI = 3.4-36.8; P < 0.0001) were significantly associated with POI. There was no significant association between OT and occurrence of POI (HR = 0.6, 95% CI = 0.2-1.9; P = 0.41). CONCLUSIONS: OT did not appear to modify risk of POI in this historic cohort of long-term survivors of HL treated with gonadotoxic therapy. Modern fertility preservation modalities, such as mature oocyte cryopreservation, should be offered to at-risk patients whenever feasible.

Frailty in childhood cancer survivors.

Young adult childhood cancer survivors are at an increased risk of frailty, a physiologic phenotype typically found among older adults. This phenotype is associated with new-onset chronic health conditions and mortality among both older adults and childhood cancer survivors. Mounting evidence suggests that poor fitness, muscular weakness, and cognitive decline are common among adults treated for childhood malignancies, and that risk factors for these outcomes are not limited to those treated with cranial radiation. Although the pathobiology of this phenotype is not known, early cellular senescence, sterile inflammation, and mitochondrial dysfunction in response to initial cancer or treatment-related insults are hypothesized to play a role. To the authors' knowledge, interventions to prevent or remediate frailty among childhood cancer survivors have not been tested to date. Pharmaceutical, nutraceutical, and lifestyle interventions have demonstrated some promise.

Genetic and clinical factors associated with obesity among adult survivors of childhood cancer: A report from the St. Jude Lifetime Cohort.

BACKGROUND: The objective of this study was to identify treatment and genetic factors associated with obesity among childhood cancer survivors. METHODS: Participants included 1996 survivors who previously received treatment for cancer at St. Jude Children's Research Hospital and who survived ≥10 years from diagnosis (median age at diagnosis, 7.2 years; median age at follow-up, 32.4 years). Obesity was defined as a body mass index ≥30 kg/m(2) . The factors associated with adult obesity were identified by subgroup-specific (cranial radiation [CRT] exposure status) multivariable logistic regression. Single nucleotide polymorphisms (SNPs) associated with obesity were identified by subgroup-specific, exploratory, genome-wide association analyses using a 2-stage resampling approach with a type I error rate of 5 × 10(-6) . RESULTS: Forty-seven percent of survivors who received CRT and 29.4% of those who did not receive CRT were obese at evaluation. In multivariable analyses, abdominal/pelvic radiation exposure was associated with decreased prevalence of obesity among survivors regardless of CRT status (P < .0001). The odds of obesity were increased among survivors who received CRT who had also received glucocorticoids (P = .014) or who were younger at diagnosis (P = .013). Among the survivors who had received CRT, 166 SNPs were associated with obesity. The strongest association was observed with reference SNP rs35669975 (P = 3.3 × 10(-8) ) on segment 33.3 of the long arm of chromosome 13 (13q33.3), approximately 30 kb downstream of FAM155A (family with sequence similarity 155, member A). SNPs within the glycine receptor α3 (GLRA3) gene and near the sex-determining region Y box 11 (SOX11) and cadherin 18 type 2 (CDH18) genes also were identified. These genes have been implicated in neural growth, repair, and connectivity. CONCLUSIONS: Obesity in childhood cancer survivors remains associated with previous exposure to CRT and glucocorticoids. Genetic variants related to neural connectivity may modify the risk of obesity among survivors who receive CRT. Validation of these findings in independent cohorts is required.

Validity of anthropometric measurements for characterizing obesity among adult survivors of childhood cancer: A report from the St. Jude Lifetime Cohort Study.

BACKGROUND: Childhood cancer survivors (CCSs) are at risk for obesity. The purpose of this project was to determine which clinical measures of body composition are most accurate among CCSs in comparison with dual-energy x-ray absorptiometry (DXA). METHODS: The agreement between the body mass index (BMI), skinfold percent body fat, and waist-to-height ratio (WHtR) and DXA was evaluated among 1361 CCSs (mean age, 32.4 ± 7.7 years) 10 or more years after the diagnosis. The sensitivity and specificity of BMI, skinfold, and WHtR obesity classifications were calculated with respect to DXA. Log-binomial regression, stratified by sex, was used to evaluate treatment-related factors for misclassification as nonobese by BMI, skinfolds, and WHtR. RESULTS: The mean body fat values were 23.3% ± 7.7% (males) and 32.3% ± 8.1% (females) for skinfolds and 26.9% ± 7.4% (males) and 38.4% ± 7.7% (females) for DXA. Pearson correlations between skinfolds and DXA were high (R = 0.83 for males, R = 0.84 for females). Skinfolds incorrectly classified 34.5% of obese males and 27.3% of obese females. BMI measures were the least sensitive with false-negative rates of 46.4% (males) and 53.1% (females). Males exposed to abdominal/pelvic radiation were at increased risk for misclassification as nonobese by BMI (relative risk, 1.57; 95% confidence interval, 1.25-1.95). The percentages classified as obese were highest with DXA (males, 63.1%; females, 84.8%) and lowest with BMI (males, 35.7%; females, 39.7%). Although skinfolds and WHtR underestimated the percentage classified as obese in comparison with DXA, the differences were not as large. CONCLUSIONS: Findings suggest that skinfolds and WHtR are better than BMI for obesity classification in CCSs. Clinicians should be aware of the high risk of misclassifying obese CCSs as nonobese.

Evaluation of a two-step iterative resampling procedure for internal validation of genome-wide association studies.

Genome-wide association studies (GWAS) have successfully identified many common genetic variants associated with complex diseases over the past decade. The 'gold standard' method for validating the top single nucleotide polymorphisms (SNPs) identified in GWAS is to independently replicate the findings in similar or diverse large-scale external cohorts. However, for rare diseases, it can be difficult to find an external validation cohort within a reasonable timeframe. In such situations, resampling methods, such as the two-step iterative resampling (TSIR) approach have been used to identify SNPs associated with the outcome of interest. However, the TSIR approach involves choosing several parameters in each step, which can influence the performance of the approach. In this paper, we undertook extensive simulation studies to assess the effect of choice of different parameters on the type I error and power for both binary and continuous phenotypes and also compared the TSIR approach with the traditional one-stage (OS) and two-stage (TS) GWAS analysis. We illustrate the usefulness of the TSIR approach by applying it to a GWAS of childhood cancer survivors. Our results indicate that the TSIR approach with an at least 70:30 split and a cutoff of discovering and replicating SNPs at least 20 times in 100 replications provides conservative type I error control and has near 'optimal' power for internally validated SNPs. Its performance is comparable with the TS GWAS for which an external validation cohort is available with only slight reduction in power in some situations. It has almost the same power as OS GWAS with conservative type I error which leads to fewer false positive findings. TSIR is a powerful and efficient method for identifying and internally validating SNPs for GWAS when independent cohorts for external validation may not be available.

Associations of seven measures of biological age acceleration with frailty and all-cause mortality among adult survivors of childhood cancer in the St. Jude Lifetime Cohort.

Survivors of childhood cancer may experience accelerated biological aging, resulting in premature frailty and death. We used seven measures of biological age in the St. Jude Lifetime (SJLIFE) Cohort to compare biological age acceleration between the SJLIFE Cohort and the third United States National Health and Nutrition Examination Survey controls, explore trajectories of biological age according to cancer treatment and type, and test associations of biological age acceleration with frailty and death (mean follow-up of 26.5 years) among survivors. Survivors of cancer aged 5% faster per year and measured, on average, 0.6-6.44 years biologically older compared to controls and 5-16 years biologically older compared to age-matched individuals at the population level. Survivors treated with hematopoietic cell transplant and vinca alkaloid chemotherapy evidenced the fastest trajectories of biological aging. Biologically, older and faster-aging survivors consistently and robustly had a higher risk of frailty and died earlier than those with slower biological aging, suggesting a potential opportunity to intervene on excess aging.

Prediabetes and Associated Risk of Cardiovascular Events and Chronic Kidney Disease Among Adult Survivors of Childhood Cancer in the St Jude Lifetime Cohort.

PURPOSE: Little is known about the prevalence of prediabetes and associated risk of cardiovascular events and chronic kidney disease (CKD) with this reversable condition in survivors. METHODS: Prevalence of prediabetes (fasting plasma glucose 100-125 mg/dL or hemoglobin A1c 5.7%-6.4%) and diabetes was clinically assessed in 3,529 adults ≥5 years from childhood cancer diagnosis and 448 controls stratified by age. Cox proportional hazards regression estimated progression from prediabetes to diabetes, and risk of future cardiac events, stroke, CKD, and death. RESULTS: Among survivors, median age 30 years (IQR, 18-65), and the prevalence of prediabetes was 29.2% (95% CI, 27.7 to 30.7) versus 18.1% (14.5 to 21.6) in controls and of diabetes was 6.5% (5.7 to 7.3) versus 4.7% (2.7 to 6.6). By age 40-49 years, more than half of the survivors had prediabetes (45.5%) or diabetes (14.0%). Among 695 survivors with prediabetes and longitudinal follow-up, 68 (10%; median follow-up, 5.1 years) progressed to diabetes. After adjustment for demographic factors and body composition, risk of progression was associated with radiation exposure to the pancreatic tail ≥10 Gy (hazard ratio [HR], 2.7 [95% CI, 1.1 to 6.8]) and total-body irradiation (4.4 [1.5 to 13.1]). Compared with survivors with normal glucose control, adjusting for relevant treatment exposures, those with prediabetes were at increased risk of future myocardial infarction (HR, 2.4 [95% CI, 1.2 to 4.8]) and CKD (2.9 [1.04 to 8.15]), while those with diabetes were also at increased risk of future cardiomyopathy (3.8 [1.4 to 10.5]) or stroke (3.4 [1.3 to 8.9]). CONCLUSION: Prediabetes is highly prevalent in adult survivors of childhood cancer and independently associated with an increased risk of future cardiovascular and kidney complications. Prediabetes, a modifiable risk factor among childhood cancer survivors, represents a new target for intervention that may prevent subsequent morbidity and mortality.