The Value of IgM Memory B-Cells in the Assessment of Splenic Function in Childhood Cancer Survivors at Risk for Splenic Dysfunction: A DCCSS-LATER Study.

Background: Childhood cancer survivors (CCS) who received radiotherapy involving the spleen or total body irradiation (TBI) might be at risk for splenic dysfunction. A comprehensive screening test for examining splenic dysfunction is lacking. Objective: We investigated whether IgM memory B-cells could be used to assess splenic dysfunction in CCS who received a splenectomy, radiotherapy involving the spleen, or TBI. Methods: All CCS were enrolled from the DCCSS-LATER cohort. We analyzed differences in IgM memory B-cells and Howell-Jolly bodies (HJB) in CCS who had a splenectomy (n = 9), received radiotherapy involving the spleen (n = 36), or TBI (n = 15). IgM memory B-cells < 9 cells/µL was defined as abnormal. Results: We observed a higher median number of IgM memory B-cells in CCS who received radiotherapy involving the spleen (31 cells/µL, p=0.06) or TBI (55 cells/µL, p = 0.03) compared to CCS who received splenectomy (20 cells/µL). However, only two CCS had IgM memory B-cells below the lower limit of normal. No difference in IgM memory B-cells was observed between CCS with HJB present and absent (35 cells/µL vs. 44 cells/µL). Conclusion: Although the number of IgM memory B-cells differed between splenectomized CCS and CCS who received radiotherapy involving the spleen or TBI, only two CCS showed abnormal values. Therefore, this assessment cannot be used to screen for splenic dysfunction.

Hypertension in long-term childhood cancer survivors after treatment with potentially nephrotoxic therapy; DCCSS-LATER 2: Renal study.

PURPOSE: To evaluate the prevalence of and risk factors for hypertension in childhood cancer survivors (CCSs) who were treated with potentially nephrotoxic therapies. METHODS: In the Dutch Childhood Cancer Survivor Study LATER cohort part 2 renal study, 1024 CCS ≥5 years after diagnosis, aged ≥18 years at study participation, treated between 1963 and 2001 with nephrectomy, abdominal radiotherapy, total body irradiation (TBI), cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide (≥1 g/m2 per single dose or ≥10 g/m2 total) or haematopoietic stem cell transplantation participated and 500 controls from Lifelines. Hypertension was defined as blood pressure (BP) (mmHg) systolic ≥140 and/or diastolic ≥90 or receiving medication for diagnosed hypertension. At the study visit, the CKD-EPI 2012 equation including creatinine and cystatin C was used to estimate the glomerular filtration rate (GFR). Multivariable regression analyses were used. For ambulatory BP monitoring (ABPM), hypertension was defined as BP daytime: systolic ≥135 and/or diastolic ≥85, night time: systolic ≥120 and/or diastolic ≥70, 24-h: systolic ≥130 and/or diastolic ≥80. Outcomes were masked hypertension (MH), white coat hypertension and abnormal nocturnal dipping (aND). RESULTS: Median age at cancer diagnosis was 4.7 years (interquartile range, IQR 2.4-9.2), at study 32.5 years (IQR 27.7-38.0) and follow-up 25.5 years (IQR 21.4-30.3). The prevalence of hypertension was comparable in CCS (16.3%) and controls (18.2%). In 12% of CCS and 17.8% of controls, hypertension was undiagnosed. A decreased GFR (<60 ml/min/1.73 m2) was associated with hypertension in CCS (OR 3.4, 95% CI 1.4-8.5). Risk factors were abdominal radiotherapy ≥20 Gy and TBI. The ABPM-pilot study (n = 77) showed 7.8% MH, 2.6% white coat hypertension and 20.8% aND. CONCLUSION: The prevalence of hypertension was comparable among CCS who were treated with potentially nephrotoxic therapies compared to controls, some of which were undiagnosed. Risk factors were abdominal radiotherapy ≥20 Gy and TBI. Hypertension and decreased GFR were associated with CCS. ABPM identified MH and a ND.

Possible modification of BRSK1 on the risk of alkylating chemotherapy-related reduced ovarian function.

STUDY QUESTION: Do genetic variations in the DNA damage response pathway modify the adverse effect of alkylating agents on ovarian function in female childhood cancer survivors (CCS)? SUMMARY ANSWER: Female CCS carrying a common BR serine/threonine kinase 1 (BRSK1) gene variant appear to be at 2.5-fold increased odds of reduced ovarian function after treatment with high doses of alkylating chemotherapy. WHAT IS KNOWN ALREADY: Female CCS show large inter-individual variability in the impact of DNA-damaging alkylating chemotherapy, given as treatment of childhood cancer, on adult ovarian function. Genetic variants in DNA repair genes affecting ovarian function might explain this variability. STUDY DESIGN, SIZE, DURATION: CCS for the discovery cohort were identified from the Dutch Childhood Oncology Group (DCOG) LATER VEVO-study, a multi-centre retrospective cohort study evaluating fertility, ovarian reserve and risk of premature menopause among adult female 5-year survivors of childhood cancer. Female 5-year CCS, diagnosed with cancer and treated with chemotherapy before the age of 25 years, and aged 18 years or older at time of study were enrolled in the current study. Results from the discovery Dutch DCOG-LATER VEVO cohort (n = 285) were validated in the pan-European PanCareLIFE (n = 465) and the USA-based St. Jude Lifetime Cohort (n = 391). PARTICIPANTS/MATERIALS, SETTING, METHODS: To evaluate ovarian function, anti-Müllerian hormone (AMH) levels were assessed in both the discovery cohort and the replication cohorts. Using additive genetic models in linear and logistic regression, five genetic variants involved in DNA damage response were analysed in relation to cyclophosphamide equivalent dose (CED) score and their impact on ovarian function. Results were then examined using fixed-effect meta-analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Meta-analysis across the three independent cohorts showed a significant interaction effect (P = 3.0 × 10-4) between rs11668344 of BRSK1 (allele frequency = 0.34) among CCS treated with high-dose alkylating agents (CED score ≥8000 mg/m2), resulting in a 2.5-fold increased odds of a reduced ovarian function (lowest AMH tertile) for CCS carrying one G allele compared to CCS without this allele (odds ratio genotype AA: 2.01 vs AG: 5.00). LIMITATIONS, REASONS FOR CAUTION: While low AMH levels can also identify poor responders in assisted reproductive technology, it needs to be emphasized that AMH remains a surrogate marker of ovarian function. WIDER IMPLICATIONS OF THE FINDINGS: Further research, validating our findings and identifying additional risk-contributing genetic variants, may enable individualized counselling regarding treatment-related risks and necessity of fertility preservation procedures in girls with cancer. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the PanCareLIFE project that has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no 602030. In addition, the DCOG-LATER VEVO study was funded by the Dutch Cancer Society (Grant no. VU 2006-3622) and by the Children Cancer Free Foundation (Project no. 20) and the St Jude Lifetime cohort study by NCI U01 CA195547. The authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.