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Background: Survivors of childhood central nervous system (CNS) tumors can develop motor and sensory impairment from their cancer and treatment history. We estimated the prevalence of motor and sensory impairment in survivors compared with controls through clinical assessment and identified associated treatment exposures and functional, quality of life (QOL), and social outcomes. Methods: Survivors of childhood CNS tumors from the St. Jude Lifetime Cohort (n = 378, median [range] age 24.0 [18.0–53.0] years, 43.4% female) ≥5 years from diagnosis and controls (n = 445, median [range] age 34.0 [18.0–70.0] years, 55.7% female) completed in‐person evaluation for motor and sensory impairment using the modified Total Neuropathy Score. Impairment was graded by modified Common Terminology Criteria for Adverse Events. Multivariable models estimated associations between grade ≥2 motor/sensory impairment, individual/treatment characteristics, and secondary outcomes (function by Physical Performance Test, fitness by physiologic cost index, QOL by Medical Outcomes Survey Short Form‐36 physical/mental summary scores, social attainment). Results: Grade ≥2 motor or sensory impairment was more prevalent in survivors (24.1%, 95% Confidence Interval [CI] 19.8%–29.4%) than controls (2.9%, CI 1.4–4.5%). Among survivors, in multivariable models, motor impairment was associated with vinca exposure <15 mg/m2 versus none (OR 4.38, CI 1.06–18.08) and etoposide exposure >2036 mg/m2 versus none (OR 12.61, CI 2.19–72.72). Sensory impairment was associated with older age at diagnosis (OR 1.09, CI 1.01–1.16) and craniospinal irradiation versus none (OR 4.39, CI 1.68–11.50). There were lower odds of motor/sensory impairment in survivors treated in the year 2000 or later versus before 1990 (Motor: OR 0.29, CI 0.10–0.84, Sensory: OR 0.35, CI 0.13–0.96). Motor impairment was associated with impaired physical QOL (OR 2.64, CI 1.22–5.72). Conclusions: In survivors of childhood CNS tumors, motor and sensory impairment is prevalent by clinical assessment, especially after exposure to etoposide, vinca, or craniospinal radiation. Treating motor impairment may improve survivors' QOL. [ABSTRACT FROM AUTHOR]

Objective: To examine associations between neurologic late effects and attainment of independence in adult survivors of childhood cancer treated with central nervous system (CNS)‐directed therapies. Methods: A total of 7881 survivors treated with cranial radiation therapy (n = 4051; CRT) and/or intrathecal methotrexate (n = 4193; IT MTX) ([CNS‐treated]; median age [range] = 25.5 years [18–48]; time since diagnosis = 17.7 years [6.8–30.2]) and 8039 without CNS‐directed therapy reported neurologic conditions including stroke, seizure, neurosensory deficits, focal neurologic dysfunction, and migraines/severe headaches. Functional independence was assessed using latent class analysis with multiple indicators (independent living, assistance with routine and personal care needs, ability to work/attend school, attainment of driver's license, marital/partner status). Multivariable regression models, adjusted for age, sex, race/ethnicity, and chronic health conditions, estimated odds ratios (OR) or relative risks (RR) for associations between neurologic morbidity, functional independence, and emotional distress. Results: Among CNS‐treated survivors, three classes of independence were identified: (1) moderately independent, never married, and non‐independent living (78.7%); (2) moderately independent, unable to drive (15.6%); and (3) non‐independent (5.7%). In contrast to 50% of non‐CNS‐treated survivors and 60% of siblings, a fourth fully independent class of CNS‐treated survivors was not identified. History of stroke (OR = 2.50, 95% CI: 1.70–3.68), seizure (OR = 9.70, 95% CI: 7.37–12.8), neurosensory deficits (OR = 2.67, 95% CI: 2.16–3.31), and focal neurologic dysfunction (OR = 3.05, 95% CI: 2.40–3.88) were associated with non‐independence among CNS‐treated survivors. Non‐independence was associated with emotional distress symptoms. Interpretation: CNS‐treated survivors do not attain full independence comparable to non‐CNS‐treated survivors or siblings. Interventions to promote independence may be beneficial for survivors with treatment‐related neurological sequalae. [ABSTRACT FROM AUTHOR]

Background: Although pediatric lower extremity sarcoma once was routinely treated with amputation, multiagent chemotherapy as well as the evolution of tumor resection and reconstruction techniques have enabled the wide adoption of limb salvage surgery (LSS). Even though infection and tumor recurrence are established risk factors for early amputation (< 5 years) after LSS, the frequency of and factors associated with late amputation (≥ 5 years from diagnosis) in children with sarcomas are not known. Additionally, the resulting psychosocial and physical outcomes of these patients compared with those treated with primary amputation or LSS that was not complicated by subsequent amputation are not well studied. Studying these outcomes is critical to enhancing the quality of life of patients with sarcomas. Questions/purposes: (1) How have treatments changed over time in patients with lower extremity sarcoma who are included in the Childhood Cancer Survivor Study (CCSS), and did primary treatment with amputation or LSS affect overall survival at 25 years among patients who had survived at least 5 years from diagnosis? (2) What is the cumulative incidence of amputation after LSS for patients diagnosed with pediatric lower extremity sarcomas 25 years after diagnosis? (3) What are the factors associated with time to late amputation (≥ 5 years after diagnosis) in patients initially treated with LSS for lower extremity sarcomas in the CCSS? (4) What are the comparative social, physical, and emotional health-related quality of life (HRQOL) outcomes among patients with sarcoma treated with primary amputation, LSS without amputation, or LSS complicated by late amputation, as assessed by CCSS follow-up questionnaires, the SF-36, and the Brief Symptom Inventory-18 at 20 years after cancer diagnosis? Methods: The CCSS is a long-term follow-up study that began in 1994 and is coordinated through St. Jude Children's Research Hospital. It is a retrospective study with longitudinal follow-up of more than 38,000 participants treated for childhood cancer when younger than 21 years at one of 31 collaborating institutions between 1970 and 1999 in the United States and Canada. Participants were eligible for enrollment in the CCSS after they had survived 5 years from diagnosis. Within the CCSS cohort, we included participants who had a diagnosis of lower extremity sarcoma treated with primary amputation (547 patients with a mean age at diagnosis of 13 ± 4 years) or primary LSS (510 patients with a mean age 14 ± 4 years). The LSS cohort was subdivided into LSS without amputation, defined as primary LSS without amputation at the time of latest follow-up; LSS with early amputation, defined as LSS complicated by amputation occurring less than 5 years from diagnosis; or LSS with late amputation, defined as primary LSS in study patients who subsequently underwent amputation 5 years or more from cancer diagnosis. The cumulative incidence of late amputation after primary LSS was estimated. Cox proportional hazards regression with time-varying covariates identified factors associated with late amputation. Modified Poisson regression models were used to compare psychosocial, physical, and HRQOL outcomes among patients treated with primary amputation, LSS without amputation, or LSS complicated by late amputation using validated surveys. Results: More study participants were treated with LSS than with primary amputation in more recent decades. The overall survival at 25 years in this population who survived 5 years from diagnosis was not different between those treated with primary amputation (87% [95% confidence interval [CI] 82% to 91%]) compared with LSS (88% [95% CI 85% to 91%]; p = 0.31). The cumulative incidence of amputation at 25 years after cancer diagnosis and primary LSS was 18% (95% CI 14% to 21%). With the numbers available, the cumulative incidence of late amputation was not different among study patients treated in the 1970s (27% [95% CI 15% to 38%]) versus the 1980s and 1990s (19% [95% CI 13% to 25%] and 15% [95% CI 10% to 19%], respectively; p = 0.15). After controlling for gender, medical and surgical treatment variables, cancer recurrence, and chronic health conditions, gender (hazard ratio [HR] 2.02 [95% CI 1.07 to 3.82]; p = 0.03) and history of prosthetic joint reconstruction (HR 2.58 [95% CI 1.37 to 4.84]; p = 0.003) were associated with an increased likelihood of late amputation. Study patients treated with a primary amputation (relative risk [RR] 2.04 [95% CI 1.15 to 3.64]) and LSS complicated by late amputation (relative risk [RR] 3.85 [95% CI 1.66 to 8.92]) were more likely to be unemployed or unable to attend school than patients treated with LSS without amputation to date. The CCSS cohort treated with primary amputation and those with LSS complicated by late amputation reported worse physical health scores than those without amputation to date, although mental and emotional health outcomes did not differ between the groups. Conclusion: There is a substantial risk of late amputation after LSS, and both primary and late amputation status are associated with decreased physical HRQOL outcomes. Children treated for sarcoma who survive into adulthood after primary amputation and those who undergo late amputation after LSS may benefit from interventions focused on improving physical function and reaching educational and employment milestones. Efforts to improve the physical function of people who have undergone amputation either through prosthetic design or integration into the residuum should be supported. Understanding factors associated with late amputation in the setting of more modern surgical approaches and implants will help surgeons more effectively manage patient expectations and adjust practice to mitigate these risks over the life of the patient. Level of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: Over 50% of childhood cancer survivors are exercise intolerant, with maximal aerobic capacities comparable to individuals decades older, suggesting early physiologic ageing. In addition, 36% of survivors are obese. Optimal exercise capacity provides a foundation to support daily function and healthy body habitus and is associated with benefits to cognition, cardiovascular health, and longevity. Cellular senescence and inflammation are key mechanisms that drive age-related disease, quantifiable as biomarkers in peripheral blood. Aims: This study aimed to evaluate associations between p16INKa, a biomarker of cellular senescence, and inflammation and exercise capacity among adult survivors of childhood cancer. Materials and methods: Eligible survivors were recruited from the St. Jude Lifetime (SJLIFE) Cohort Study. Exercise capacity was assessed by maximal oxygen uptake (VO2, ml/kg/min) obtained via cardiopulmonary exercise testing using a modified Bruce protocol. Body fat (%) was determined fromdual energy xray absorptiometry (DEXA). Peripheral blood samples were used to evaluate log2 p16INK4a mRNA expression, a biomarker of cellular senescence, and inflammation with high sensitivity C-reactive protein (hs-CRP) levels. Multivariable regression evaluated associations between p16INK4a, hs-CRP, body fat, and exercise capacity. Results: Participants included 185 five-year childhood cancer survivors (mean age 36.6 [range 20.1 - 55.7] years, 44% male, 77% non-Hispanic white, 53% leukemia/lymphoma). Compared to males, females had lower peak VO2 (mean ± SD, 22.5 ± 8.2 vs. 28.8 ± 7.7 ml/kg/min, p<0.01), higher p16INK4a expression (9.6 ± 1.2 vs. 9.2 ± 1.2 fold, p=0.02), and hs-CRP concentration (5.9 ± 8.4 vs. 3.3 ± 3.9 mg/L, p=0.01). Among females (n=103), hs-CRP concentration (β -0.2, 95% CI -0.34 to -0.05, p=0.01) and p16INK4a expression (β-5.32, 95% CI 10.42 to -0.22, p=0.04) were inversely associated and statistically significant with peak exercise capacity, with a significant interaction between p16INK4a expression and body fat (β 0.15, 95% CI 0.02 to 0.28, p=0.03). Among males (n=82), p16INK4a expression (β -1.01, 95% CI -2.14 to 0.12, p=0.08), and body fat (b -0.54, 95% CI -0.70 to -0.38, p<0.01) were inversely associated with peak exercise capacity. Conclusion: Inflammation and p16INK4a expression, a biomarker of cellular senescence, are associated with lower exercise capacity in childhood cancer survivors, suggesting potential targets or outcome measures for interventions designed to prevent or remediate accelerated physiologic ageing in this population. [ABSTRACT FROM AUTHOR]

In the context of high-throughput data, the differences in continuous markers between two groups are usually assessed by ordering the p-values obtained from the two-sample pooled t-test or Wilcoxon-Mann-Whitney test and choosing a stringent cutoff such as 10-8 to control the family-wise error rate (FWER) or false discovery rate (FDR). All markers with p-values below the cutoff are declared to be significantly associated with the phenotype. This inherently assumes that the test procedure provides valid type I error estimates in extreme tails of the null distribution. The aforementioned tests assume homoscedasticity in the two groups, and the t-test further assumes underlying distributions to be normally distributed. Cao et al. (Biometrika, 2013, 100, 495-502) have shown that in the context of multiple hypotheses testing the approach based on FDR may not be valid under non-normality and/or heteroscedasticity. Therefore, having a test statistic that is robust to these violations is needed. In this study, we propose a robust analog of Behrens-Fisher statistic based on trimmed means, conduct an extensive simulation study to compare its performance with other competing approaches, and demonstrate its usefulness by applying it to DNA methylation data used by Teschendorff et al. (Genome Res., 2010, 20, 440-446). An R program to implement the proposed method is provided in the Supplementary Material. [ABSTRACT FROM AUTHOR]

The bathtub failure rate lifetime data is modelled by the use of a simple generalization of the Weibull distribution. The Weibull generalization is also used in the testing of goodness-of-fit of the Weibull and negative exponential model as subhypotheses. Several problems arising during reliability analysis are solved by the negative exponential model, which provides simple, closed-form solutions.