Kala Y. Kamdar

Cardiovascular Risk Factors in Adult Survivors of Pediatric Cancer—A Report from the Childhood Cancer Survivor Study

Background: Childhood cancer survivors are at higher risk of morbidity and mortality from cardiovascular disease compared with the general population. Methods: Eight thousand five hundred ninety-nine survivors (52% male) and 2,936 siblings (46% male) from the Childhood Cancer Survivor Study, a retrospectively ascertained, prospectively followed study of persons who survived 5 years after childhood cancer diagnosed from 1970 to 1986, were evaluated for body mass index of ≥30 kg/m2 based on self-reported heights and weights and self-reported use of medications for hypertension, dyslipidemia, and impaired glucose metabolism. The presence of three or more of the above constituted Cardiovascular Risk Factor Cluster (CVRFC), a surrogate for Metabolic Syndrome. Results: Survivors were more likely than siblings to take medications for hypertension [odds ratio (OR), 1.9; 95% confidence interval (95% CI), 1.6-2.2], dyslipidemia (OR, 1.6; 95% CI, 1.3-2.0) or diabetes (OR, 1.7; 95% CI, 1.2-2.3). Among these young adults (mean age of 32 years for survivors and 33 years for siblings), survivors were not more likely than siblings to be obese or have CVRFC. In a multivariable logistic regression analysis, factors associated with having CVRFC included older age at interview [≥40 versus <30 years of age (OR, 8.2; 95% CI, 3.5-19.9)], exposure to total body irradiation (OR, 5.5; 95% CI, 1.5-15.8) or radiation to the chest and abdomen (OR, 2.3; 95% CI, 1.2-2.4), and physical inactivity (OR, 1.7; 95% CI, 1.1-2.6). Conclusions: Among adult survivors of pediatric cancer, older attained age, exposure to total body irradiation or abdominal plus chest radiation, and a sedentary life-style are associated with CVRFC. Cancer Epidemiol Biomarkers Prev; 19(1); 170–81

Screening for Neurocognitive Impairment in Pediatric Cancer Long-Term Survivors

PURPOSE Recent studies suggest that up to 40% of childhood cancer survivors may experience neurocognitive problems, a finding that has led the Childrens Oncology Group to recommend regular evaluation. However, for a variety of reasons, including costs, time restraints, health insurance, and access to professional resources, these guidelines are often difficult to implement. We report reliability and validity data on a brief neurocognitive screening method that could be used to routinely screen patients in need of comprehensive follow-up. PATIENTS AND METHODS Two hundred forty consecutive patients were screened during their annual visits to a long-term survivor clinic using standard neurocognitive measures and brief parent rating. From this total, 48 patients had a second screening, and 52 patients had a comprehensive follow-up evaluation. Test-retest reliability and predictive and discriminative validity were examined. RESULTS Good test-retest reliability was demonstrated, with an overall r = 0.72 and all individual subtest correlations greater than r = 0.40. Although means tended to improve from first to second testing, no significant changes were detected (all P > .10). The screen accurately predicted global intellect (F(6,45) = 11.81, P < .0001), reading skills (F(6,45) = 4.74, P < .001), and mathematics (F(6,45) = 3.35, P < .008). Parent rating was a marginal indicator of global intellect only. CONCLUSION The brief neurocognitive screening was a better predictor of child functioning than specific parent rating. This brief measure, which can be completed in 30 minutes, is a practical and reliable method to identify cancer survivors in need of further neurocognitive follow-up.

A meta‐analysis of MTHFR C677T and A1298C polymorphisms and risk of acute lymphoblastic leukemia in children

Methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms have been implicated in childhood acute lymphoblastic leukemia (ALL) risk, but previously published studies were inconsistent and recent meta‐analyses were not adequate.

Posttransplant lymphoproliferative disease following liver transplantation.

Purpose of reviewDespite contemporary immunosuppressive regimens, posttransplant lymphoproliferative disease (PTLD) remains a major complication after liver transplantation. This review highlights advances in the understanding of the pathophysiology, diagnosis, and management of PTLD in liver transplant recipients. Recent findingsThe spectrum of PTLD after liver transplant ranges from polymorphic lymphoproliferation to high-grade monoclonal lymphoma and is usually related to outgrowth of lymphocytes infected with Epstein–Barr virus (EBV). Risk factors for PTLD include EBV-seronegativity of the recipient, young age, intensity of immunosuppression, and the first year posttransplant. Measurement of EBV load by quantitative polymerase chain reaction assays is an important aid in the surveillance and diagnosis of PTLD although the specificity for PTLD is only about 50% (specificity for EBV is ∼100%). In patients diagnosed with PTLD, management options include reduction of immunosuppression, rituximab, combination chemotherapy, and adoptive immunotherapy. Outcomes have improved because rituximab has been incorporated into treatment regimens, and immunotherapy approaches show promise. SummaryPTLD is a significant complication after liver transplantation, particularly in children. Advances in early detection approaches have aided in the diagnosis and management of PTLD, but further research to identify better predictive biomarkers is needed to improve risk-based treatment strategies.

Folate pathway polymorphisms predict deficits in attention and processing speed after childhood leukemia therapy

Neurocognitive impairment occurs in 20–40% of childhood acute lymphoblastic leukemia (ALL) survivors, possibly mediated by folate depletion and homocysteine elevation following methotrexate treatment. We evaluated the relationship between folate pathway polymorphisms and neurocognitive impairment after childhood ALL chemotherapy.

Pediatric Hodgkin Lymphoma: Are We Over-Scanning Our Patients?

Despite the favorable outcome of most pediatric patients with Hodgkin lymphoma (HL), there is rising concern about risks of carcinogenesis from both diagnostic and therapeutic radiation exposure for patients treated on study protocols. Although previous studies have investigated radiation exposure during treatment, radiation from post-treatment surveillance imaging may also increase the likelihood of secondary malignancies. All diagnostic imaging examinations involving ionizing radiation exposure performed for surveillance following completion of therapy were recorded for 99 consecutive pediatric patients diagnosed with HL from 2000 to 2010. Cumulative radiation dosage from these examinations and the frequency of relapse detection by these examinations were recorded. In the first 2 years following completion of therapy, patients in remission received a median of 11 examinations (range 0–26). Only 13 of 99 patients relapsed, 11 within 5 months of treatment completion. No relapse was detected by 1- or 2-view chest radiographs (n = 38 and 296, respectively), abdomen/pelvis computed tomography (CT) scans (n = 211), or positron emission tomography (PET) scans alone (n = 11). However, 10/391 (2.6%) of chest CT scans, 4/364 (1.1%) of neck CT scans, and 3/47 (6.4%) of PET/CT scans detected relapsed disease. Thus, only 17 scans (1.3%) detected relapse in a total of 1358 scans. Mean radiation dosages were 31.97 mSv for Stage 1, 37.76 mSv for Stage 2, 48.08 mSv for Stage 3, and 51.35 mSv for Stage 4 HL. Approximately 1% of surveillance imaging examinations identified relapsed disease. Given the very low rate of relapse detection by surveillance imaging stipulated by current protocols for pediatric HL patients, the financial burden of the tests themselves, the high cure rate, and risks of second malignancy from ionizing radiation exposure, modification of the surveillance strategy is recommended.

Gene-Environment Interactions and the Risk of Childhood Acute Lymphoblastic Leukemia: Exploring the Role of Maternal Folate Genes and Folic Acid Fortification

Few studies have evaluated the interaction of folic acid fortification and folate metabolic genes on the risk of childhood acute lymphoblastic leukemia (ALL). Because folate status is influenced by both intake and genetic variation, the objective of this study was to explore maternal folate metabolic gene-folic acid fortification interactions and the risk of childhood ALL. The study population consisted of 120 ALL case-parent triads recruited from Texas Childrens Cancer Center between 2003 and 2010. For this analysis, we focused on 13 maternal single nucleotide polymorphisms (SNPs) in 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR). Prefortification was defined as delivery before January 1997 and postfortification as delivery in or after January 1997. We used a two-step approach to evaluate gene-environment interactions. First, a case-only approach was used, as this design provides greater power in the assessment of gene-environment interactions compared to other approaches. Second, we confirmed all statistically significant interactions using a log-linear approach among case-parent triads. Only one of 13 interactions evaluated was confirmed in step 2. Specifically, mothers with the minor allele of MTR rs1804742 and who delivered during the prefortification period were at a greater risk of having a child with ALL (OR = 1.54, 95% CI: 0.82–2.88), compared to those mothers who delivered during the postfortification period (OR = 0.81, 95% CI: 0.22–2.99, P for interaction = .03). In one of the few studies to evaluate maternal folate metabolic genotype-folic acid interactions, we found limited evidence that the maternal MTR rs1804742 appeared to interact with higher folic acid levels to influence childhood ALL risk.

Pediatric Burkitt's lymphoma and diffuse B-cell lymphoma: are surveillance scans required?

Outcomes in pediatric B-Non-Hodgkin Lymphoma (B NHL) have improved with intensive chemotherapy protocols, with long-term survival now over 80%. However, long-term adverse effects of therapy and poor outcomes for patients who relapse remain challenges. In this study, we aimed to evaluate the potential risks and benefits of routine relapse surveillance imaging after the completion of therapy. We reviewed 44 B NHL patients diagnosed and treated at Texas Childrens Cancer Center in the period between 2000 to 2011. All cross-sectional diagnostic imaging examinations performed for disease assessment after completion of chemotherapy were reviewed and cumulative radiation dosage from these examinations and the frequency of relapse detection by these examinations were recorded. Only 3 patients of the 44 relapsed (6.8%), though none of the relapses were initially diagnosed by computed tomography (CT) or fludeoxyglucose positron emission tomography (FDG-PET) scans. Median effective dose of ionizing radiation per patient was 40.3 mSv with an average of 49.1 mSv (range 0–276 mSv). This single-institution study highlights the low relapse rate in pediatric B-NHL with complete response at the end of therapy, the low sensitivity of early detection of relapse with surveillance CT or FDG-PET imaging, and the costs and potential increased risk of secondary malignancies from cumulative radiation exposure from surveillance imaging. We propose that routine surveillance CT or FDG-PET scans for these patients may not be necessary.

Genetic markers in a multi-ethnic sample for childhood acute lymphoblastic leukemia risk.

Abstract Genome-wide association studies have identified multiple risk loci for childhood acute lymphoblastic leukemia (ALL), but mostly in European/White populations, despite Hispanics having a greater risk. We re-examined single nucleotide polymorphisms (SNPs) of known associations with childhood ALL and known human leukocyte antigen (HLA) region lymphoma risk markers in a multi-ethnic population. Significant associations were found in two ARID5B variants (rs7089424 and rs10821936). We replicated a strong risk association in non-Hispanic White males with rs2395185, a protective marker for lymphoma. Another HLA region marker, rs2647012, showed a risk association among Hispanics only, while a strong protective association was found with rs1048456, a follicular lymphoma risk marker. Our study validated this new case–control sample by confirming genetic markers associated with childhood ALL, and yielded new associations with lymphoma markers. Despite positive results, our study did not provide any clues as to why Hispanics have a higher susceptibility to childhood leukemia, suggesting that environmental factors may have a strong contribution.

Examination of HFE associations with childhood leukemia risk and extension to other iron regulatory genes

Hereditary hemochromatosis (HFE) variants correlating with body iron levels have shown associations with cancer risk, including childhood acute lymphoblastic leukemia (ALL). Using a multi-ethnic sample of cases and controls from Houston, TX, we examined two HFE variants (rs1800562 and rs1799945), one transferrin receptor gene (TFRC) variant (rs3817672) and three additional iron regulatory gene (IRG) variants (SLC11A2 rs422982; TMPRSS6 rs855791 and rs733655) for their associations with childhood ALL. Being positive for either of the HFE variants yielded a modestly elevated odds ratio (OR) for childhood ALL risk in males (1.40, 95% CI=0.83-2.35), which increased to 2.96 (95% CI=1.29-6.80) in the presence of a particular TFRC genotype for rs3817672 (P interaction=0.04). The TFRC genotype also showed an ethnicity-specific association, with increased risk observed in non-Hispanic Whites (OR=2.54, 95% CI=1.05-6.12; P interaction with ethnicity=0.02). The three additional IRG SNPs all showed individual risk associations with childhood ALL in males (OR=1.52-2.60). A polygenic model based on the number of variant alleles in five IRG SNPs revealed a linear increase in risk among males with the increasing number of variants possessed (OR=2.0 per incremental change, 95% CI=1.29-3.12; P=0.002). Our results replicated previous HFE risk associations with childhood ALL in a US population and demonstrated novel associations for IRG SNPs, thereby strengthening the hypothesis that iron excess mediated by genetic variants contributes to childhood ALL risk.