Risk Of Fatal Cancer Research Articles

Complex Social-Ecological Systems Network：New Perspective on the Sustainability

The complex social-ecological systems network is an integrative platform of ecology, economy, management and complex networks which providing a new perspective on the comprehensive management of ecological and socio economical processes. Through research of the structures, functions and processes, one four-dimensional conceptual model of the complex social-ecological system for sustainable development was set up. The complex social-ecological systems comprise of natural subsystem, social subsystem, economic subsystem and integrative decision subsystem. The complex social-ecological systems network was defined as one six-element tuple which denotes the comprehensive spatial structure with different kinds of nodes of ecosystem, social system and economic system. The complex social-ecological systems network has some important characteristics including hierarchies, power-low, vulnerabilities, resilience, dynamics, co-evolution of flow and structure, et al. At last, based on the Multimedia Environment Pollutant Assessment System (MEPAS) of US EPA, the relationship between POPs (Persistent Organic Pollutants) exposure and lifetime fatal cancer risk was studied, and comprehensive risk network of the Taihu basin water pollution and human body health was established.

Radiation Exposure During Pediatric Videourodynamics

Videourodynamics is useful for evaluating and treating neurological disorders in children. Traditional urodynamic parameters can be obtained while simultaneous visualization of the urinary system can reveal anatomical anomalies. This additional information comes at the cost of radiation exposure to the child. We characterized radiation exposure from videourodynamics. We reviewed all recent videourodynamic studies and recorded patient demographics, urological diagnoses, physical attributes, total fluoroscopy time, total radiation exposure in mGy, bladder capacity and the number of filling cycles performed. Multivariate linear regression was used to identify patient factors that independently influenced total radiation exposure. A total of 64 videourodynamic studies were performed in 34 female and 28 male patients with a mean age of 8.6 years (95% CI 7.2-10.0). The most common diagnosis was neurogenic bladder in 40 patients, although 49 had multiple diagnoses. Mean total fluoroscopy time was 1.8 minutes (95% CI 1.4-2.1) and mean total radiation exposure was 10 mGy (95% CI 7.5-13.3). On multivariate linear regression patient weight and bladder capacity were the only independent predictors of total radiation exposure. Videourodynamics entail significant radiation exposure. Patient weight and bladder capacity were independent predictors of total radiation exposure. Physician awareness of radiation exposure may result in the judicious use of fluoroscopy and aid in counseling parents on the risk of videourodynamics. Further research is needed to quantify organ specific doses of radiation due to medical imaging in children and the associated cancer risks.

Blood Pressure and Risk of Incident and Fatal Cancer in the Metabolic Syndrome and Cancer Project (Me-Can) — Analysis of Seven Prospective Cohorts

Blood Pressure and Risk of Incident and Fatal Cancer in the Metabolic Syndrome and Cancer Project (Me-Can) — Analysis of Seven Prospective Cohorts

Genetic Variants in the LEPR, CRY1, RNASEL, IL4, and ARVCF Genes Are Prognostic Markers of Prostate Cancer-Specific Mortality

Prostate cancer is the second leading cause of cancer-related deaths in men, accounting for more than 30,000 deaths annually. The purpose of this study was to test whether variation in selected candidate genes in biological pathways of interest for prostate cancer progression could help distinguish patients at higher risk for fatal prostate cancer. In this hypothesis-driven study, we genotyped 937 single nucleotide polymorphisms (SNPs) in 156 candidate genes in a population-based cohort of 1,309 prostate cancer patients. We identified 22 top-ranking SNPs (P ≤ 0.01, FDR ≤ 0.70) associated with prostate cancer-specific mortality (PCSM). A subsequent validation study was completed in an independent population-based cohort of 2,875 prostate cancer patients. Five SNPs were validated (P ≤ 0.05) as being significantly associated with PCSM, one each in the LEPR, CRY1, RNASEL, IL4, and ARVCF genes. Compared with patients with 0 to 2 of the at-risk genotypes those with 4 to 5 at-risk genotypes had a 50% (95% CI, 1.2-1.9) higher risk of PCSM and risk increased with the number of at-risk genotypes carried (P(trend) = 0.001), adjusting for clinicopathologic factors known to influence prognosis. Five genetic markers were validated to be associated with lethal prostate cancer. This is the first population-based study to show that germline genetic variants provide prognostic information for prostate cancer-specific survival. The clinical utility of this five-SNP panel to stratify patients at higher risk for adverse outcomes should be evaluated.

Excess Cancer Risk Assessment from Some Common X-Ray Examinations in Sabzevar County

Introduction: Nowadays ionizing radiation has a considerable contribution in medical diagnostic and treatment. Using ionizing radiation is increasing rapidly, so biological effects of ionizing radiation should be considered more. X-rays in the range of diagnostic radiology have hazardous effects and risks that are defined as random effects. These effects obey the LNT hypothesis that occur at low doses and include many types of cancer and genetic mutations. So it is very important to assess the risk of exposure in medical examinations. Cancer is one of these hazardous risks caused by low dose ionizing radiation that may occur during life after exposure. According to BEAR 7, low dose radiation is defined as radiation that produces doses near zero up to 100 mSv. Materials and Methods: This work was carried out in eight radiology centers in the Sabzevar county of Iran for 485 patients in eight typical x-ray examinations chosen for the study: chest PA, chest AP, lumbar spine AP, lumbar spine LAT, pelvis AP, abdomen AP, skull AP and Lat. In order to estimate the excess cancer risk, we need to obtain collective effective dose caused by radiation in the study population. Usually effective dose offers precise assessment of radiography examination injuries in adult patients. In this study, we used the PCXMC Monte Carlo based software to obtain effective dose and organ dose. This software calculates organ and effective dose following input of patient and radiographic conditions. Results: Average patient weight and height, entrance surface dose, parameters used for each type of examination, and DAP values were entered. Effective dose, collective effective dose, number of radiographs per year and the excess cancer risk arising from these radiographic examinations were then calculated. Discussion and Conclusion: Excess risk of fatal cancer due to x-ray examinations in the study population was calculated by collective effective dose. This risk in the population is about 0.42 cases suffering fatal cancer per year in this county. If the doses from other diagnostic radiology procedures, in which absorbed dose to patients are considerably higher than conventional radiography, are added to this amount, then the excess risk will be significantly greater than that obtained in this assessment.

Body mass index in early and middle-late adulthood and risk of localised, advanced and fatal prostate cancer: a population-based prospective study

Background:The relationships between body mass index (BMI) during early and middle-late adulthood and incidence of prostate cancer (PCa) by subtype of the disease (localised, advanced) and fatal PCa is unclear.Methods:A population-based cohort of 36 959 Swedish men aged 45–79 years was followed up from January 1998 through December 2008 for incidence of PCa (1530 localised and 554 advanced cases were diagnosed) and through December 2007 for PCa mortality (225 fatal cases).Results:From a competing-risks analysis, incidence of localised PCa was observed to be inversely associated with BMI at baseline (middle-late adulthood; rate ratio (RR) for 35 kg m–2 when compared with 22 kg m–2 was 0.69 (95% CI 0.52–0.92)), but not at age 30. For fatal PCa, BMI at baseline was associated with a nonstatistically significant increased risk (RR for every five-unit increase: 1.12 (0.88–1.43)) and BMI at age 30 with a decreased risk (RR for every five-unit increase: 0.72 (0.51–1.01)).Conclusion:Our results indicate an inverse association between obesity during middle-late, but not early adulthood, and localised PCa. They also suggest a dual association between BMI and fatal PCa – a decreased risk among men who were obese during early adulthood and an increased risk among those who were obese during middle-late adulthood.

Evaluation of risk of secondary cancer occurrence after proton radiotherapy of ocular tumours

Abstract Reduction of undesired exposure to scattered neutron and gamma radiation associated with proton therapy should reduce the risk of occurrence of secondary cancers, especially in paediatric patients. By replacing the patient with a RANDO ® antropomorphic phantom, we determined the undesired radiation doses during the entire course of treatment at the ocular proton radiotherapy facility at IFJ PAN in Krakow and estimated the associated risk of secondary cancers. The highest exposure from the scattered radiation, per therapeutic proton absorbed dose, was found in the brain close to the target volume. Using TASTRAK PADC track detectors we estimated the fast neutron dose equivalent in the brain at 15.2 μSv/Gy, a value consistent with 17.06 μSv/Gy obtained from MCNPX 2.5.0 Monte Carlo calculations. The ambient dose equivalent, H ∗ (10), determined with WENDI II and FHT 192 detectors at the position of the patient (50 cm below the isocentre), was 2.41 μSv/Gy from neutrons and 0.43 μSv/Gy from γ -rays, respectively. Based on estimated values of organ dose equivalents, we evaluate the whole-body risk of fatal secondary cancers per course of treatment at below 0.001%.

Dose assessment of the patient and the helper in emergency head computed tomography

Abstract Computed Tomography (CT) becomes more and more important and is frequently used in modern diagnostic techniques. CT offers an effective diagnosis on lesion and pathology; however, it also delivers a radiation dose to patients. Besides, in some special emergency cases, the patient may require someone to help him in the examination room to perform the head CT, due to the patient lost intellectual and operational capacity. This study evaluated the delivered radiation dose and the risk of radiation-induced cancer for the patient and for the helper after carrying out the emergent head CT examination. A Rando phantom with thermoluminescent dosimeter (TLD) chips inside relevant organs was used to simulate the patient during head CT examination. An effective dose of 2.06 ± 0.16 mSv and 1.46 ± 0.07 mSv without and with wearing the lead apron were found respectively, considering ICRP 60 recommendation. ICRP 103 recommendations the readings would have been 1.29 ± 0.15 mSv and 0.71 ± 0.04 mSv. The effective dose determined from the dose-length product (DLP) method (2.19 mSv) was similar to the value (2.06 ± 0.16 mSv) estimated by TLD method considering the ICRP 60 recommendation (without lead apron). Assuming a 5% total risk for fatal cancer per Sv in the general population, risk of radiation-induced cancer for patients were 1.03 × 10 −2 % (without lead apron) and 7.80 × 10 −3 % (with lead apron) for ICRP 60, and were 6.45 × 10 −3 % (without lead apron) and 3.55 × 10 −3 % (with lead apron) for ICRP 103. The dose received by the helper was assessed by wearing a personal badge. The helper during emergent head CT examination may receive a personal dose equivalent ( H p (10)) of 19.36 ± 5.89 μSv and 138.81 ± 101.28 μSv with and without lead apron, respectively, at distance of 0.3–1 m from the center of CT scanner. Based on the observed dose reduction of a factor of 7.17 we recommend that helpers wear lead apron in the CT examination room.

Teenage motherhood and risk of premature death: long-term follow-up in the ONS Longitudinal Study

Teenage motherhood is relatively common in the UK, but little is known about related health inequalities in this population. We estimated cause-specific mortality risks over three decades in a nationally representative cohort. We examined premature mortality in a 1.1% sample of all women who were teenagers in England and Wales during the 1970s, 1980s and 1990s using data from the Office for National Statistics Longitudinal Study (ONS LS). Our primary outcome was suicide. Long-term follow-up to 31 December 2006, to a potential maximum age of 49 years, was achieved through near-complete routine linkage to national mortality records. We created a time-dependent exposure variable, with relative risks estimated according to age when women first experienced motherhood versus a reference group of those currently without children. Women who were teenage mothers were around 30% more likely to die prematurely by any cause and almost 60% more likely to die unnaturally, whereas first-time motherhood at mature age conferred lower risk compared to women without children. Teenage motherhood was associated with a more than doubled risk of suicide [mortality rate ratio (MRR) 2.23, 95% confidence interval (CI) 1.30-3.83], and elevated risks of fatal cancer of the cervix and lung were also found. Changing the reference category to first-time mothers at 20 years and above also revealed a significant elevation in risk of accidental death. The complex psychosocial needs of these women require greater attention from clinicians, public health professionals, social services and policymakers. Their elevated risk of poor health outcomes may persist well beyond the actual teenage motherhood years.

Familial Mortality and Familial Incidence in Cancer

An overwhelming majority of data on familial risk in cancer is based on incident cancer, whereas familiality in cancer mortality is largely unknown. If fatal form of cancer was a highly familial subtype, then familial risk for mortality may exceed that of incidence, which would be particularly relevant for clinical decision making and counseling. The individuals in the nationwide Swedish Family-Cancer Database were classified according to family history of fatal and nonfatal cancer. Familial risks of incident and fatal concordant cancer were calculated for offspring based on their parental family history using a Cox model with hazard ratio (HR); offspring without family history were the reference. Most HRs for offspring incident cancers were somewhat higher for fatal compared with nonfatal parental family history. For breast (HR, 1.87 fatal v 1.66 nonfatal; P < .001) and prostate (HR, 2.30 fatal v 1.84 nonfatal; P < .001) cancers, 51.0% of patients with familial breast cancer and 56.6% of patients with prostate cancer had fatal family history. HRs for death in offspring according to a fatal compared with nonfatal family history were significantly increased for colorectal (HR, 1.76 v 1.47, respectively; P = .02), breast (HR, 1.97 v 1.51, respectively; P = .002), and prostate (HR, 2.03 v 1.59, respectively; P = .002) cancers. TNM classification did not seem to differ between the family histories. We showed also that an overwhelming proportion of offspring were diagnosed after the parental death. Familial breast, prostate, and colorectal cancers might have a yet unidentified genetic component associated with poorer survival. It may be useful to record survival data in family history records.

Collective radiation dose from diagnostic x-ray examination in nine public hospitals in Addis Ababa, Ethiopia

Background: Medical x-ray exposures have the largest man made source of population exposure to ionizing radiation in different countries. Recent developments in medical imaging have led to rapid increases in a number of high dose xray examinations performed with significant consequences for individual patient doses and for collective dose to the population as a whole. It is therefore important in each country to make regular assessments of the magnitude of these large doses.Objectives: To calculate collective dose of the population as a result of radiation dose from diagnostic x-rays, thereby to estimate the annual incidence of cancer which would be reduced by the use of rare earth intensifying screen.Methods: Data on the number of diagnostic procedures using x-ray examination in year 2007 in nine governmental hospitals, excluding military hospitals, by body site were collected in Addis Ababa. The number of examinations of specific body site was multiplied by the average effective dose per examination to get the collective dose over the population. Based on International Commission on Radiological Protection (ICRP) the fatality risk of fatal cancers (5% per Sv) was estimated.Results: In this study, the annual collective dose over the population is 31.21manSv (0.0.42mSv per person). Based on ICRP fatality risk of 500 fatal cancers per 10,000 man-sieverts (5% per Sv), estimation of incidence of fatal cancers cases in year 2007 was 2 cases half of which can be reduced by adoption of rare earth screens.Conclusion: Although the use of ionizing radiation for diagnostic medical procedures is an acceptable part of modern medicine, there is also the potential for inappropriate use and unnecessary radiation dose to the patient, so the request of radiography must be justified. It is estimated that the adoption of rare earth screen technology might reduce the annual incidence of cancer which would be fatal after an average latency period of 18.4 years by half, hence this research recommended adopting rare earth screen technology in Ethiopia. [Ethiop. J. Health Dev. 2010;24(2):140-144]

CHEMICAL AND RADIOACTIVE CARCINOGENS IN CIGARETTES: ASSOCIATED HEALTH IMPACTS AND RESPONSES OF THE TOBACCO INDUSTRY, U.S. CONGRESS, AND FEDERAL REGULATORY AGENCIES

²¹⁰Po and ²¹⁰Pb were discovered in tobacco in 1964. This was followed by detailed assessments of the nature of their deposition, and accompanying dose rates to the lungs of cigarette smokers. Subsequent studies revealed: (1) the sources and pathways through which they gain access to tobacco; (2) the mechanisms through which they preferentially deposit in key segments of the bronchial epithelium; and (3) the fact that the accompanying alpha radiation plays a synergistic role in combination with the chemical carcinogens, to increase the fatal cancer risk coefficient in cigarette smokers by a factor of 8 to 25. Nonetheless, it was not until 2009 that Congress mandated that the Food and Drug Administration require that the cigarette industry reveal the presence of these carcinogens. In the meantime, cigarette smoking has become not only the number one source of cancer deaths in the United States, but also a major contributor to heart disease and other health impacts. If the latter effects are included, smoking is estimated to have caused an average of 443,000 deaths and 5.1 million years of potential life lost among the U.S. population each year from 2000 through 2004. The estimated associated collective dose is more than 36 times that to the workers at all the U.S. nuclear power plants, U.S. Department of Energy nuclear weapons facilities, and crews of all the vessels in the U.S. Nuclear Navy. This unnecessary source of lung cancer deaths demands the utmost attention of the radiation protection and public health professions.

Long-term effect of aspirin on colorectal cancer incidence and mortality: 20-year follow-up of five randomised trials

High-dose aspirin (≥500 mg daily) reduces long-term incidence of colorectal cancer, but adverse effects might limit its potential for long-term prevention. The long-term effectiveness of lower doses (75-300 mg daily) is unknown. We assessed the effects of aspirin on incidence and mortality due to colorectal cancer in relation to dose, duration of treatment, and site of tumour. We followed up four randomised trials of aspirin versus control in primary (Thrombosis Prevention Trial, British Doctors Aspirin Trial) and secondary (Swedish Aspirin Low Dose Trial, UK-TIA Aspirin Trial) prevention of vascular events and one trial of different doses of aspirin (Dutch TIA Aspirin Trial) and established the effect of aspirin on risk of colorectal cancer over 20 years during and after the trials by analysis of pooled individual patient data. In the four trials of aspirin versus control (mean duration of scheduled treatment 6·0 years), 391 (2·8%) of 14 033 patients had colorectal cancer during a median follow-up of 18·3 years. Allocation to aspirin reduced the 20-year risk of colon cancer (incidence hazard ratio [HR] 0·76, 0·60-0·96, p=0·02; mortality HR 0·65, 0·48-0·88, p=0·005), but not rectal cancer (0·90, 0·63-1·30, p=0·58; 0·80, 0·50-1·28, p=0·35). Where subsite data were available, aspirin reduced risk of cancer of the proximal colon (0·45, 0·28-0·74, p=0·001; 0·34, 0·18-0·66, p=0·001), but not the distal colon (1·10, 0·73-1·64, p=0·66; 1·21, 0·66-2·24, p=0·54; for incidence difference p=0·04, for mortality difference p=0·01). However, benefit increased with scheduled duration of treatment, such that allocation to aspirin of 5 years or longer reduced risk of proximal colon cancer by about 70% (0·35, 0·20-0·63; 0·24, 0·11-0·52; both p<0·0001) and also reduced risk of rectal cancer (0·58, 0·36-0·92, p=0·02; 0·47, 0·26-0·87, p=0·01). There was no increase in benefit at doses of aspirin greater than 75 mg daily, with an absolute reduction of 1·76% (0·61-2·91; p=0·001) in 20-year risk of any fatal colorectal cancer after 5-years scheduled treatment with 75-300 mg daily. However, risk of fatal colorectal cancer was higher on 30 mg versus 283 mg daily on long-term follow-up of the Dutch TIA trial (odds ratio 2·02, 0·70-6·05, p=0·15). Aspirin taken for several years at doses of at least 75 mg daily reduced long-term incidence and mortality due to colorectal cancer. Benefit was greatest for cancers of the proximal colon, which are not otherwise prevented effectively by screening with sigmoidoscopy or colonoscopy. None.

Associations between an Obesity Related Genetic Variant (FTO rs9939609) and Prostate Cancer Risk

Observational studies suggest that obese men have a lower risk of incident prostate cancer, but an increased risk of advanced and fatal cancers. These observations could be due to confounding, detection bias, or a biological effect of obesity. Genetic studies are less susceptible to confounding than observational epidemiology and can suggest how associations between phenotypes (such as obesity) and diseases arise. To determine whether the associations between obesity and prostate cancer are causal, we conducted a genetic association study of the relationship between a single nucleotide polymorphism known to be associated with obesity (FTO rs9939609) and prostate cancer. Data are from a population-based sample of 1550 screen-detected prostate cancers, 1815 age- and general practice matched controls with unrestricted prostate specific antigen (PSA) values and 1175 low-PSA controls (PSA <0.5 ng/ml). The rs9939609 A allele, which was associated with higher BMI in the sample, was inversely associated with overall (odds ratio (OR) versus all controls = 0.93; 95% confidence interval (CI): 0.85–1.02 p = 0.12 per allele) and low-grade (OR = 0.90; 0.81–0.99 p = 0.03 per allele) prostate cancer risk, but positively associated with high-grade cancer among cases (OR high- versus low-grade cancer = 1.16; 0.99–1.37 p = 0.07 per allele). Although evidence for these effects was weak, they are consistent with observational data based on BMI phenotypes and suggest that the observed association between obesity and prostate cancer is not due to confounding. Further research should confirm these findings, extend them to other BMI-related genetic variants and determine whether they are due to detection bias or obesity-related hormonal changes.Trial RegistrationControlled-Trials.com ISRCTN20141297

Osteoclast differentiation factor RANKL controls development of progestin-driven mammary cancer

Breast cancer is one of the most common cancers in humans and will on average affect up to one in eight women in their lifetime in the United States and Europe. The Women's Health Initiative and the Million Women Study have shown that hormone replacement therapy is associated with an increased risk of incident and fatal breast cancer. In particular, synthetic progesterone derivatives (progestins) such as medroxyprogesterone acetate (MPA), used in millions of women for hormone replacement therapy and contraceptives, markedly increase the risk of developing breast cancer. Here we show that the in vivo administration of MPA triggers massive induction of the key osteoclast differentiation factor RANKL (receptor activator of NF-κB ligand) in mammary-gland epithelial cells. Genetic inactivation of the RANKL receptor RANK in mammary-gland epithelial cells prevents MPA-induced epithelial proliferation, impairs expansion of the CD49f(hi) stem-cell-enriched population, and sensitizes these cells to DNA-damage-induced cell death. Deletion of RANK from the mammary epithelium results in a markedly decreased incidence and delayed onset of MPA-driven mammary cancer. These data show that the RANKL/RANK system controls the incidence and onset of progestin-driven breast cancer.

Risk assessment of baseline outdoor gamma dose rate levels study of natural radiation sources in Bursa, Turkey

Within the scope of this study, gamma radiation dose rate measurements have been carried out in the province of Bursa. The mean outdoor (terrestrial and cosmic) gamma dose rate in this area was 90 nGy h(-1). The cosmic gamma dose rate was measured to be 16 nGy h(-1) at the Iznik lake in the region. The mean annual effective dose due to outdoor gamma radiations was determined to be 110.4 µSv. The collective effective dose equivalent was calculated to be 3.21 × 10(2) man Sv per year. The average relative excess lifetime risk of fatal cancer was calculated at 4.50 × 10(-4) for the people living in the city. The activity concentrations of natural radionuclides such as (238)U series, (232)Th series, (40)K and fission products like (137)Cs in surface soil samples were measured by using an HPGe-based gamma spectrometry system. The mean activity concentration of (238)U series, (232)Th series, (40)K and (137)Cs were found to be 55.9 Bq kg(-1) for (226)Ra, 23.6 Bq kg(-1) for (214)Pb, 22.5 Bq kg(-1) for (214)Bi, 31.3 Bq kg(-1) for (208)Tl, 32.9 Bq kg(-1) for (228)Ac, 430 Bq kg(-1) for (40)K and 5.4 Bq kg(-1) for (137)Cs. The radiation hazards associated with the radionuclides were estimated at an average of 136 Bq kg(-1) by calculating the radium equivalent activity (Ra(eq)). The mean calculated value of the external hazard index (H(ex)) for the soil was found to be 0.37.

Radiation Dose from Computed Tomography in Patients with Necrotizing Pancreatitis: How Much Is Too Much?

ObjectivesLow-dose ionizing radiation from medical imaging has been indirectly linked with subsequent cancer. Computed tomography (CT) is the gold standard for defining pancreatic necrosis. The primary goal was to identify the frequency and effective radiation dose of CT imaging for patients with necrotizing pancreatitis. MethodsAll patients with necrotizing pancreatitis (2003–2007) were retrospectively analyzed for CT-related radiation exposure. ResultsNecrosis was identified in 18% (238/1290) of patients with acute pancreatitis (mean age = 53 years; hospital/ICU length of stay = 23/7 days; mortality = 9%). A median of five CTs/patient [interquartile range (IQR) = 4] were performed during a median 2.6-month interval. The average effective dose was 40 mSv per patient (equivalent to 2,000 chest X-rays; 13.2 years of background radiation; one out of 250 increased risk of fatal cancer). The actual effective dose was 63 mSv considering various scanner technologies. CTs were infrequently (20%) followed by direct intervention (199 interventional radiology, 118 operative, 12 endoscopic) (median = 1; IQR = 2). Magnetic resonance imaging did not have a CT-sparing effect. Mean direct hospital costs increased linearly with CT number (R = 0.7). ConclusionsThe effective radiation dose received by patients with necrotizing pancreatitis is significant. Management changes infrequently follow CT imaging. The ubiquitous use of CT in necrotizing pancreatitis raises substantial public health concerns and mandates a careful reassessment of its utility.

Radiation Doses and Cancer Risks from Breast Imaging Studies

To compare radiation doses and lifetime attributable risks (LARs) of radiation-induced cancer incidence and mortality from breast imaging studies involving the use of ionizing radiation. Recent literature on radiation doses from radiologic procedures and organ doses from nuclear medicine procedures, along with Biologic Effects of Ionizing Radiation (BEIR) VII age-dependent risk data, is used to estimate LARs of radiation-induced cancer incidence and mortality from breast imaging studies involving ionizing radiation, including screen-film mammography, digital mammography, digital breast tomosynthesis, dedicated breast computed tomography, breast-specific gamma imaging (BSGI), and positron emission mammography (PEM). Two-view digital mammography and screen-film mammography involve average mean glandular radiation doses of 3.7 and 4.7 mGy, respectively. According to BEIR VII data, these studies are associated, respectively, with LARs of fatal breast cancer of 1.3 and 1.7 cases per 100,000 women aged 40 years at exposure and less than one case per one million women aged 80 years at exposure. Annual screening digital or screen-film mammography performed in women aged 40-80 years is associated with an LAR of fatal breast cancer of 20-25 cases in 100,000. A single BSGI study involving a label-recommended dose of 740-1100 MBq (20-30 mCi) of technetium 99m-sestamibi is estimated to involve an LAR of fatal cancer that is 20-30 times that of digital mammography in women aged 40 years. A single PEM study involving a labeled dose of 370 MBq (10 mCi) of fluorine 18 fluorodeoxyglucose is estimated to involve an LAR of fatal cancer that is 23 times higher than that of digital mammography in women aged 40 years. A single BSGI or PEM study is associated with a fatal radiation-induced cancer risk higher than or comparable to that of annual screening mammography in women aged 40-80 years.

Blood pressure, body size and prostate cancer risk in the Swedish Construction Workers cohort

Data from prospective studies on blood pressure and prostate cancer risk are limited, and results are inconclusive. Baseline measurements of height, weight and blood pressure were available in 336,159 men in the Swedish Construction Workers cohort. During an average of 22.2 years of follow-up, 10,002 incident cases and 2,601 fatal cases of prostate cancer were identified in National registers. For 5,219 cases, tumor characteristics were available; 2,817 tumors were classified as nonaggressive and 2,402 as aggressive. Relative risks of disease were estimated from Cox regression models, using attained age as time-scale, and adjusting for birth year, smoking status and body mass index (BMI). Top compared to bottom quintile level of systolic or diastolic blood pressure was associated with a significant 15-20% decreased risk of incident prostate cancer (p for trend: systolic < 0.0001, diastolic = 0.3), but blood pressure was not significantly associated with risk of fatal prostate cancer. BMI was not associated with prostate cancer incidence, but was positively associated with fatal prostate cancer; men in the top quintile had a 30% increased risk (p for trend = 0.0004). The associations between blood pressure and BMI and nonaggressive tumors were similar to those of incident prostate cancer, and associations with aggressive tumors were similar to those of fatal prostate cancer. Data from our study suggest that hypertension is associated with a decreased risk of incident prostate cancer, but the explanation for this finding is unclear. Our study support a positive association between overweight and risk of fatal prostate cancer.

Estimation of organs doses and radiation-induced secondary cancer risk from scattered photons for conventional radiation therapy of nasopharynx: a Monte Carlo study

We used Monte Carlo modeling to calculate the organs doses due to out-of field photons during radiation therapy of the nasopharynx. A medical internal radiation dose (MIRD)-based mathematical phantom resembling an adult man was modeled by MCNP4C MC code. Three validated models of a cobalt-60 machine, a 6-MV photon beam of a Varian 2300 C/D linac, and a 9-MV photon beam of a Neptun linac were used to simulate the isocentric irradiation of a mathematical phantom with two lateral fields of the nasopharynx. The organspecific dose, effective dose, and cancer risk estimates were obtained. The effective doses for out-of-field radiation were 320, 295, and 248 mSv for the (60)Co beam, 6-MV beam, and 9-MV beam devices, respectively, for a 70-Gy tumor dose. The fatal cancer risks of 1.6%, 1.5%, and 1.2% were estimated for a 70-Gy tumor dose of (60)Co and the 6- and 9-MV photon beams, respectively. Our results regarding the effective dose and cancer risk are in agreement with previously published experimental results on conventional radiation therapy. Further investigation on patients' out-of-field dose to provide more knowledge on various radiotherapy techniques is suggested.