MYC copy number and mRNA expression in chronic lymphocytic leukemia patients exposed to ionizing radiation due to the Chornobyl NPP accident.

Some clinical and biological features indicating an unfavorable course of the disease were found in ionizing radiation (IR) - related chronic lymphocytic leukemia (CLL) patients. The MYC proto-oncogene is considered to contribute to CLL pathogenesis. Increased MYC copy number is associated with poor prognosis in CLL. AIM: To investigate the frequency of MYC gene copy number amplification in IR-exposed CLL patients and relate the findings to the MYC mRNA levels, the presence of unfavourable prognosis mutations (TP53, SF3B1, NOTCH1), and patient`s outcome. MATERIALS AND METHODS: The analysis of MYC copy number was carried out by real-time quantitative polymerase chain reaction (PCR) in 70 IR-exposed CLL patients. The MYC mRNA expression was measured by real-time quantitative reverse transcription PCR. RESULTS: Increased MYC gene copy number was present in 5.7% of cases. There was a statistically significant association between increased MYC copy number and increased MYC mRNA (p < 0.014). Additionally, somatic deletion in MYC locus was found in one patient. Most of patients (80%) with detected MYC aberrations were previously untreated, suggesting that these lesions might occur early in the course of the disease. The MYC aberrations were found mutually exclusive with high risk TP53 and SF3B1 mutations, while one case was identified, where MYC amplification and NOTCH1 mutation coincided simultaneously. Regarding clinical outcome, the MYC aberrations were associated with a shorter time to first treatment (3 vs 25 months, p = 0.008) as well as reduced overall survival (60 vs 139 months). CONCLUSION: Our data suggest that MYC aberrations might be an early event in IR-related CLL and contribute to aggressive disease development in the absence of high risk TP53 and SF3B1 mutations.

Usefulness of cancer-free survival in estimating the lifetime attributable risk of cancer incidence from radiation exposure.

Risk projection models estimating the lifetime cancer risk from radiation exposure are generally based on exposure dose, age at exposure, attained age, gender and study-population-specific factors such as baseline cancer risks and survival rates. Because such models have mostly been based on the Life Span Study cohort of Japanese atomic bomb survivors, the baseline risks and survival rates in the target population should be considered when applying the cancer risk. The survival function used in the risk projection models that are commonly used in the radiological protection field to estimate the cancer risk from medical or occupational exposure is based on all-cause mortality. Thus, it may not be accurate for estimating the lifetime risk of high-incidence but not life-threatening cancer with a long-term survival rate. Herein, we present the lifetime attributable risk (LAR) estimates of all solid cancers except thyroid cancer, thyroid cancer, and leukemia except chronic lymphocytic leukemia in South Korea for lifetime exposure to 1 mGy per year using the cancer-free survival function, as recently applied in the Fukushima health risk assessment by the World Health Organization. Compared with the estimates of LARs using an overall survival function solely based on all-cause mortality, the LARs of all solid cancers except thyroid cancer, and thyroid cancer evaluated using the cancer-free survival function, decreased by approximately 13% and 1% for men and 9% and 5% for women, respectively. The LAR of leukemia except chronic lymphocytic leukemia barely changed for either gender owing to the small absolute difference between its incidence and mortality. Given that many cancers have a high curative rate and low mortality rate, using a survival function solely based on all-cause mortality may cause an overestimation of the lifetime risk of cancer incidence. The lifetime fractional risk was robust against the choice of survival function.

Optimisation of chemotherapy and radiotherapy for untreated Hodgkin lymphoma patients with respect to second malignant neoplasms, overall and progression-free survival: individual participant data analysis.

BACKGROUND: Efficacy and the risk of severe late effects have to be well-balanced in treatment of Hodgkin lymphoma (HL). Late adverse effects include secondary malignancies which often have a poor prognosis. To synthesise evidence on the risk of secondary malignancies after current treatment approaches comprising chemotherapy and/or radiotherapy, we performed a meta-analysis based on individual patient data (IPD) from patients treated for newly diagnosed HL. OBJECTIVES: We investigated several questions concerning possible changes in the risk of secondary malignancies when modifying chemotherapy or radiotherapy (omission of radiotherapy, reduction of the radiation field, reduction of the radiation dose, use of fewer chemotherapy cycles, intensification of chemotherapy). We also analysed whether these modifications affect progression-free survival (PFS) and overall survival (OS). SEARCH METHODS: We searched MEDLINE and Cochrane CENTRAL trials databases comprehensively in June 2010 for all randomised trials in HL since 1984. Key international trials registries were also searched. The search was updated in March 2015 without collecting further IPD (one further eligible study found) and again in July 2017 (no further eligible studies). SELECTION CRITERIA: We included randomised controlled trials (RCTs) for untreated HL patients which enrolled at least 50 patients per arm, completed recruitment by 2007 and performed a treatment comparison relevant to our objectives. DATA COLLECTION AND ANALYSIS: Study groups submitted IPD, including age, sex, stage and the outcomes secondary malignant neoplasm (SMN), OS and PFS as time-to-event data. We meta-analysed these data using Petos method (SMN) and Cox regression with inverse-variance pooling (OS, PFS) for each of the five study questions, and performed subgroup and sensitivity analyses to assess the applicability and robustness of the results. MAIN RESULTS: We identified 21 eligible trials and obtained IPD for 16. For four studies no data were supplied despite repeated efforts, while one study was only identified in 2015 and IPD were not sought. For each study question, between three and six trials with between 1101 and 2996 participants in total and median follow-up between 6.7 and 10.8 years were analysed. All participants were adults and mainly under 60 years. Risk of bias was assessed as low for the majority of studies and outcomes. Chemotherapy alone versus same chemotherapy plus radiotherapy. Omitting additional radiotherapy probably reduces secondary malignancy incidence (Peto odds ratio (OR) 0.43, 95% confidence interval (CI) 0.23 to 0.82, low quality of evidence), corresponding to an estimated reduction of eight-year SMN risk from 8% to 4%. This decrease was particularly true for secondary acute leukemias. However, we had insufficient evidence to determine whether OS rates differ between patients treated with chemotherapy alone versus combined-modality (hazard ratio (HR) 0.71, 95% CI 0.46 to 1.11, moderate quality of evidence). There was a slightly higher rate of PFS with combined modality, but our confidence in the results was limited by high levels of statistical heterogeneity between studies (HR 1.31, 95% CI 0.99 to 1.73, moderate quality of evidence). Chemotherapy plus involved-field radiation versus same chemotherapy plus extended-field radiation (early stages) . There is insufficient evidence to determine whether smaller radiation field reduces SMN risk (Peto OR 0.86, 95% CI 0.64 to 1.16, low quality of evidence), OS (HR 0.89, 95% C: 0.70 to 1.12, high quality of evidence) or PFS (HR 0.99, 95% CI 0.81 to 1.21, high quality of evidence). Chemotherapy plus lower-dose radiation versus same chemotherapy plus higher-dose radiation (early stages). There is insufficient evidence to determine the effect of lower-radiation dose on SMN risk (Peto OR 1.03, 95% CI 0.71 to 1.50, low quality of evidence), OS (HR 0.91, 95% CI 0.65 to 1.28, high quality of evidence) or PFS (HR 1.20, 95% CI 0.97 to 1.48, high quality of evidence). Fewer versus more courses of chemotherapy (each with or without radiotherapy; early stages). Fewer chemotherapy courses probably has little or no effect on SMN risk (Peto OR 1.10, 95% CI 0.74 to 1.62), OS (HR 0.99, 95% CI 0.73 to1.34) or PFS (HR 1.15, 95% CI 0.91 to 1.45).Outcomes had a moderate (SMN) or high (OS, PFS) quality of evidence. Dose-intensified versus ABVD-like chemotherapy (with or without radiotherapy in each case). In the mainly advanced-stage patients who were treated with intensified chemotherapy, the rate of secondary malignancies was low. There was insufficient evidence to determine the effect of chemotherapy intensification (Peto OR 1.37, CI 0.89 to 2.10, low quality of evidence). The rate of secondary acute leukemias (and for younger patients, all secondary malignancies) was probably higher than among those who had treatment with standard-dose ABVD-like protocols. In contrast, the intensified chemotherapy protocols probably improved PFS (eight-year PFS 75% versus 69% for ABVD-like treatment, HR 0.82, 95% CI 0.7 to 0.95, moderate quality of evidence). Evidence suggesting improved survival with intensified chemotherapy was not conclusive (HR: 0.85, CI 0.70 to 1.04), although escalated-dose BEACOPP appeared to lengthen survival compared to ABVD-like chemotherapy (HR 0.58, 95% CI 0.43 to 0.79, moderate quality of evidence).Generally, we could draw valid conclusions only in terms of secondary haematological malignancies, which usually occur less than 10 years after initial treatment, while follow-up within the present analysis was too short to record all solid tumours. AUTHORS' CONCLUSIONS: The risk of secondary acute myeloid leukaemia and myelodysplastic syndrome (AML/MDS) is increased but efficacy is improved among patients treated with intensified chemotherapy protocols. Treatment decisions must be tailored for individual patients. Consolidating radiotherapy is associated with an increased rate of secondary malignancies; therefore it appears important to define which patients can safely be treated without radiotherapy after chemotherapy, both for early and advanced stages. For early stages, treatment optimisation methods such as use of fewer chemotherapy cycles and reduced field or reduced-dose radiotherapy did not appear to markedly affect efficacy or secondary malignancy risk. Due to the limited amount of long-term follow-up in this meta-analysis, further long-term investigations of late events are needed, particularly with respect to secondary solid tumours. Since many older studies have been included, possible improvement of radiotherapy techniques must be considered when interpreting these results.

Clinical characteristics of chronic lymphocytic leukemia occurring in chornobyl cleanup workers.

The recently demonstrated radiation-induction of chronic lymphocytic leukemia (CLL) raises the question as to whether the amount of radiation exposure influences any of the clinical characteristics of the disease. We evaluated the relationship between bone marrow radiation doses and clinical characteristics and survival of 79 CLL cases diagnosed during 1986-2006 in a cohort of 110 645 male workers who participated in the cleanup work of the Chornobyl nuclear accident in Ukraine in 1986. All diagnoses were confirmed by an independent International Hematology Panel. Patients were followed up to the date of death or end of follow-up on 31 October 2010. The median age at diagnosis was 57 years. Median bone marrow dose was 22.6 milligray (mGy) and was not associated with time between exposure and clinical diagnosis of CLL (latent period), age, peripheral blood lymphocyte count or clinical stage of disease in univariate and multivariate analyses. Latent period was significantly shorter among those older at first exposure, smokers and those with higher frequency of visits to the doctor prior to diagnosis. A significant increase in the risk of death with increasing radiation dose was observed (p = 0.03, hazard ratio = 2.38, 95% confidence interval: 1.11,5.08 comparing those with doses ≥22 mGy to doses <22 mGy). After adjustment for radiation dose, survival of CLL cases was significantly shorter among those with younger age at first exposure, higher peripheral blood lymphocyte count, more advanced clinical stage of disease and older age at diagnosis (all p < 0.05). This is the first study to examine association between bone marrow radiation doses from the Chornobyl accident and clinical manifestations of the CLL in Chornobyl cleanup workers. The current study provides new evidence on the association of radiation dose and younger age at first radiation exposure at Chornobyl with shorter survival after diagnosis. Future studies are necessary with more cases in order to improve the statistical power of these analyses and to determine their significance. Copyright © 2016 John Wiley & Sons, Ltd.

Mortality among military participants at the 1957 PLUMBBOB nuclear weapons test series and from leukemia among participants at the SMOKY test.

Health effects following low doses of ionizing radiation are uncertain. Military veterans at the Nevada test site (NTS) during the SMOKY atmospheric nuclear weapons test in 1957 were reported to be at increased risk for leukemia in 1979, but this increase was not evaluated with respect to radiation dose. The SMOKY test was one of 30 tests in 1957 within the PLUMBBOB test series. These early studies led to public laws where atomic veterans could qualify for compensation for presumptive radiogenic diseases. A retrospective cohort study was conducted of 12219 veterans at the PLUMBBOB test series, including 3020 at the SMOKY nuclear test. Mortality follow-up was through 2010 and observed causes of death were compared with expected causes based on general population rates. Radiation dose to red bone marrow was based on individual dose reconstructions, and Cox proportional hazards models were used to evaluate dose response for all leukemias other than chronic lymphocytic leukemia (non-CLL leukemia). Vital status was determined for 95.3% of the 12 219 veterans. The dose to red bone marrow was low (mean 3.2 mGy, maximum 500 mGy). Military participants at the PLUMBBOB nuclear test series remained relatively healthy after 53 years and died at a lower rate than the general population. In contrast, and in comparison with national rates, the SMOKY participants showed significant increases in all causes of death, respiratory cancer, leukemia, nephritis and nephrosis, and accidents, possibly related in part to lifestyle factors common to enlisted men who made up 81% of the SMOKY cohort. Compared with national rates, a statistically significant excess of non-CLL leukemia was observed among SMOKY participants (Standardized Mortality Ratio = 1.89, 95% 1.24-2.75, n = 27) but not among PLUMBBOB participants after excluding SMOKY (SMR = 0.87, 95% 0.64-1.51, n = 47). Leukemia risk, initially reported to be significantly increased among SMOKY participants, remained elevated, but this risk diminished over time. Despite an intense dose reconstruction, the risk for leukemia was not found to increase with increasing levels of radiation dose to the red bone marrow. Based on a linear model, the estimated excess relative risk per mGy is -0.05 (95% CI -0.14, 0.04). An explanation for the observed excess of leukemia remains unresolved but conceivably could be related to chance due to small numbers, subtle biases in the study design and/or high tobacco use among enlisted men. Larger studies should elucidate further the possible relationship between fallout radiation, leukemia and cancer among atomic veterans.

Chronic Lymphocytic Leukemia in Chornobyl Cleanup Workers.

This paper describes the chronic lymphocytic leukemia (CLL) incidence in a cohort of 110,645 (enlarged later to 152,520) male Ukrainian cleanup workers of the Chornobyl (Chernobyl) accident who were exposed to a range of radiation doses over the 1986-1990 time period. The standardized incidence rates are presented for a 27-y period after the exposure. For 2007-2012 period, the authors have identified the incident CLL cases in an enlarged cohort of 152,520 persons by linkage of the cohort file with the Ukrainian National Cancer Registry (NCRU). CLL data for the previous period (1987-2006) were identified in a frame of the Ukrainian-American leukemia study in the original cohort of 110,645 male clean-up workers. A significant CLL incidence excess was shown for the entire study period 1987-2012, with more prominent levels for the earliest years (1987-1996) when the standardized incidence rate (SIR) value was estimated to be 3.61 with 95% confidence interval from 2.32 to 4.91. In 2007-2012, the CLL incidence decreased substantially but still exceeded the national level although not significantly. In parallel, the several studies were performed at the National Research Center for Radiation Medicine (NRCRM) to explore if any clinical and cytogenetic features of CLL existed in the clean-up workers. The clinical study included 80 exposed and 70 unexposed CLL cases. Among the major clinical differences of the CLL course in the clean-up workers were a shorter period of white blood cells (WBC) doubling (10.7 vs. 18.0; p<0.001), frequent infectious episodes, lymphoadenopathy and hepatosplenomegaly (37 vs. 16), higher expression for CD38, and lower expression for ZAP-70 antigen.

Childhood CT scans and cancer risk: impact of predisposing factors for cancer on the risk estimates.

To investigate the role of cancer predisposing factors (PFs) on the associations between paediatric computed tomography (CT) scan exposures and subsequent risk of central nervous system (CNS) tumours and leukaemia. A cohort of children who underwent a CT scan in 2000-2010 in 23 French radiology departments was linked with the national childhood cancers registry and national vital status registry; information on PFs was retrieved through hospital discharge databases. In children without PF, hazard ratios of 1.07 (95% CI 0.99-1.10) for CNS tumours (15 cases) and 1.16 (95% CI 0.77-1.27) for leukaemia (12 cases) were estimated for each 10 mGy increment in CT x-rays organ doses. These estimates were similar to those obtained in the whole cohort. In children with PFs, no positive dose-risk association was observed, possibly related to earlier non-cancer mortality in this group. Our results suggest a modifying effect of PFs on CT-related cancer risks, but need to be confirmed by longer follow-up and other studies.

Secondary acute lymphoblastic leukemia is an independent predictor of poor prognosis.

Compared to secondary acute myeloid leukemia, secondary acute lymphoblastic leukemia (sALL) is poorly characterized. We utilized data from the Surveillance, Epidemiology, and End Results (SEER) 13 database to further elucidate patient characteristics and prognostic factors in sALL. Cases of adult de novo acute lymphoblastic leukemia (ALL) and sALL in patients with primary breast, rectum, cervix, or ovarian cancers or lymphoma with a latency period of at least 12 months were identified within the SEER 13 database. Survival in sALL and de novo ALL were compared after propensity matching based on age, gender, race, ALL subtype, and year of diagnosis. 4124 cases of de novo ALL and 79 cases of sALL were identified. sALL patients were older at diagnosis (median 62 years vs. 44 years; p<0.01). Overall survival (OS) in sALL was lower than de novo ALL (median 8 months vs. 11 months), 1 year OS: 35% vs. 47% (p=0.05), 2 year OS: 16% vs. 31% (p<0.01), and 5 year OS: 7% vs. 21% (p<0.01). Multivariate analysis revealed sALL as an independent predictor of worsened survival (adjusted HR 1.54; 95% CI 1.16-2.04, p<0.01) after propensity matching.

Simulation-extrapolation method to address errors in atomic bomb survivor dosimetry on solid cancer and leukaemia mortality risk estimates, 1950-2003.

Analyses of the Life Span Study (LSS) of Japanese atomic bombing survivors have routinely incorporated corrections for additive classical measurement errors using regression calibration. Recently, several studies reported that the efficiency of the simulation-extrapolation method (SIMEX) is slightly more accurate than the simple regression calibration method (RCAL). In the present paper, the SIMEX and RCAL methods have been used to address errors in atomic bomb survivor dosimetry on solid cancer and leukaemia mortality risk estimates. For instance, it is shown that using the SIMEX method, the ERR/Gy is increased by an amount of about 29 % for all solid cancer deaths using a linear model compared to the RCAL method, and the corrected EAR 10(-4) person-years at 1 Gy (the linear terms) is decreased by about 8 %, while the corrected quadratic term (EAR 10(-4) person-years/Gy(2)) is increased by about 65 % for leukaemia deaths based on a linear-quadratic model. The results with SIMEX method are slightly higher than published values. The observed differences were probably due to the fact that with the RCAL method the dosimetric data were partially corrected, while all doses were considered with the SIMEX method. Therefore, one should be careful when comparing the estimated risks and it may be useful to use several correction techniques in order to obtain a range of corrected estimates, rather than to rely on a single technique. This work will enable to improve the risk estimates derived from LSS data, and help to make more reliable the development of radiation protection standards.

A prognostic model of therapy-related myelodysplastic syndrome for predicting survival and transformation to acute myeloid leukemia.

INTRODUCTION/BACKGROUND: We evaluated the characteristics of a cohort of patients with myelodysplastic syndrome (MDS) related to therapy (t-MDS) to create a prognostic model. PATIENTS AND METHODS: We identified 281 patients with MDS who had received previous chemotherapy and/or radiotherapy for previous malignancy. Potential prognostic factors were determined using univariate and multivariate analyses. RESULTS: Multivariate Cox regression analysis identified 7 factors that independently predicted short survival in t-MDS: age ≥ 65 years (hazard ratio [HR], 1.63), Eastern Cooperative Oncology Group performance status 2-4 (HR, 1.86), poor cytogenetics (-7 and/or complex; HR, 2.47), World Health Organization MDS subtype (RARs or RAEB-1/2; HR, 1.92), hemoglobin (< 11 g/dL; HR, 2.24), platelets (< 50 × 10(9)/dL; HR, 2.01), and transfusion dependency (HR, 1.59). These risk factors were used to create a prognostic model that segregated patients into 3 groups with distinct median overall survival: good (0-2 risk factors; 34 months), intermediate (3-4 risk factors; 12 months), and poor (5-7 risk factors; 5 months) (P < .001) and 1-year leukemia-free survival (96%, 84%, and 72%, respectively, P = .003). This model also identified distinct survival groups according to t-MDS therapy. CONCLUSION: In summary, we devised a prognostic model specifically for patients with t-MDS that predicted overall survival and leukemia-free survival. This model might facilitate the development of risk-adapted therapeutic strategies.