Risk Of Fatal Cancer Research Articles

Cancer risk assessment after exposure from natural radionuclides in soil using Monte Carlo techniques

The purpose of this paper is to assess fatal cancer risk after external and internal (inhalation and ingestion) exposure from natural radionuclides in soil like (238)U, (232)Th, (40)K, and (226)Ra on the territory of Bela Crkva, Serbia. Although receiving doses are low from sources like natural radionuclides in soil, because of stochastic effects of ionizing radiation, risk for developing cancer exists and can be quantified. Concentrations of radionuclides from 80 soil samples are measured using HPGe detector. Fatal cancer risk is assessed from calculated ambient dose rate in the target organs of body due to external and internal exposure. Monte Carlo simulations are used to obtain conversion factors which are required to calculate absorbed dose rate in target organs. Assessed cancer risk for (238)U in the case of both inhalation and ingestion exposure is from 1.11 × 10(-6) to 24 × 10(-6) for minimal and maximal activity in soil samples, from 1.02 × 10(-6) to 23.3 × 10(-6) for exposure to (226)Ra, from 1.89 × 10(-6) to 50.3 × 10(-6) for exposure to (232)Th, and from 0.265 × 10(-6) to 9.83 × 10(-6) for exposure to (40)K. Overall risk from (40)K as external and internal source is from 0.8 × 10(-6) to 31.9 × 10(-6). Calculated cancer risks from both inhalation and ingestion exposure could be related to all tissues that are on the way of distribution of particles within the body but especially to deposition sites in the body. Assessed risks for fatal cancer development from inhaled and ingested natural radionuclides originating in soil are not increased.

Dietary vitamin K intake in relation to cancer incidence and mortality: results from the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg)

Anticarcinogenic activities of vitamin K have been observed in animal and cell studies. On the basis of the growth inhibitory effects of vitamin K as observed in a variety of cancer cell lines, we hypothesized that dietary intake of phylloquinone (vitamin K(1)) and menaquinones (vitamin K(2)) may be associated with overall cancer incidence and mortality. In the prospective EPIC-Heidelberg (European Prospective Investigation into Cancer and Nutrition-Heidelberg) cohort study, 24,340 participants aged 35-64 y and free of cancer at enrollment (1994-1998) were actively followed up for cancer incidence and mortality through 2008. Dietary vitamin K intake was estimated from food-frequency questionnaires completed at baseline by using HPLC-based food-composition data. Multivariate-adjusted hazard ratios (HRs) and 95% CIs were estimated by using Cox proportional hazards models. During a median follow-up time of >10 y, 1755 incident cancer cases occurred, of which 458 were fatal. Dietary intake of menaquinones was nonsignificantly inversely associated with overall cancer incidence (HR for the highest compared with the lowest quartile: 0.86; 95% CI: 0.73, 1.01; P for trend = 0.08), and the association was stronger for cancer mortality (HR: 0.72; 95% CI: 0.53, 0.98; P for trend = 0.03). Cancer risk reduction with increasing intake of menaquinones was more pronounced in men than in women, mainly driven by significant inverse associations with prostate (P for trend = 0.03) and lung (P for trend = 0.002) cancer. We found no association with phylloquinone intake. These findings suggest that dietary intake of menaquinones, which is highly determined by the consumption of cheese, is associated with a reduced risk of incident and fatal cancer.

Hormone therapy and fatal breast cancer.

Among unanswered questions is whether menopausal use of estrogen therapy (ET) or estrogen-plus-progestin therapy (CHT) increases risk of developing fatal breast cancer i.e., developing and dying of breast cancer. Using a population-based case-control design, we estimated incidence rate ratios of fatal breast cancer in postmenopausal hormone therapy (HT) users compared to non-users by type, duration, and recency of HT use. HT use prior to breast cancer diagnosis in 278 women who died of breast cancer within 6 years of diagnosis (cases) was compared with use in 2224 controls never diagnosed with breast cancer using conditional logistic regression. Measures taken to address potential bias and confounding inherent in case-control studies included collecting and adjusting for detailed data on demographic and other factors potentially associated both with HT use and breast cancer. Fifty-six per cent of cases and 68% of controls reported HT use. Among current 3+ year HT users, odds ratios and 95% confidence intervals for death were 0.83 (0.50, 1.38) and 0.69 (0.44, 1.09), respectively, for exclusive use of CHT or of ET, and were 0.94 (0.59, 1.48) and 0.70 (0.45, 1.07) for any use of CHT or of ET regardless of other hormone use. Point estimates suggest no increased risk of fatal breast cancer with HT use, although 50% increases in risk in longer-term current CHT users cannot be ruled out.

Metabolic Syndrome and Endometrial Carcinoma

The authors examined the association between the metabolic syndrome and risk of incident endometrial and fatal uterine corpus cancer within a large prospective cohort study. Approximately 290,000 women from Austria, Norway, and Sweden were enrolled during 1974-2005, with measurements of height, weight, systolic and diastolic blood pressure, and circulating levels of glucose, total cholesterol, and triglycerides. Relative risks were estimated using Cox proportional hazards regression. The metabolic syndrome was assessed as a composite z score, as the standardized sum of z scores for body mass index, blood pressure, glucose, cholesterol, and triglycerides. A total of 917 endometrial carcinomas and 129 fatal cancers were identified. Increased risks of incident endometrial carcinoma and fatal uterine corpus cancer were seen for the metabolic syndrome factors combined, as well as for individual factors (except for cholesterol). The relative risk of endometrial carcinoma for the metabolic syndrome was 1.37 (95% confidence interval: 1.28, 1.46) per 1-unit increment of z score. The positive associations between metabolic syndrome factors (both individually and combined) and endometrial carcinoma were confined to the heaviest women. The association between the metabolic syndrome and endometrial carcinoma risk seems to go beyond the risk conferred by obesity alone, particularly in women with a high body mass index.

Insulin-Like Growth Factor-I and Cancer Mortality in Older Men

Although numerous studies have explored the relation of IGF-I with cancer incidence, few have investigated the association between IGF-I and cancer mortality. This study examined the association of serum IGF-I levels with cancer mortality in older community-dwelling men. We conducted a prospective, population-based study of 633 men aged 50 yr and older (mean = 73) who attended a 1988-1991 research clinic visit when blood was obtained for measurement of IGF-I. Participants were followed for vital status through July 2006. All-cancer mortality was assessed. Median IGF-I was 96 ng/ml. During the 18-yr follow-up, 368 deaths occurred; 74 (20%) were due to cancer. Cox regression analyses showed a significant quadratic association between IGF-I and all-cancer mortality (P = 0.039). Higher levels of IGF-I were associated with progressively higher risk of cancer death after adjusting for age, IGF-binding protein-1, adiposity, exercise, current smoking, and previous cancer. The adjusted risk of cancer death was statistically significant for IGF-I levels above 120 ng/ml, with magnitudes of effect ranging from 1.61 [95% confidence interval (CI) = 1.28-2.02] to 2.61 (95% CI = 1.46-4.64). For the 46% of men with IGF-I above 100 ng/ml, the risk of fatal cancer was 1.82 (95% CI = 1.11-2.96) compared to the risk with lower levels. Higher serum IGF-I in older men is associated with increased risk of cancer death, independent of age, adiposity, lifestyle, and cancer history. These results suggest caution in the use of IGF-I-enhancing therapies to slow the adverse effects of aging.

Radiation dose and risk assessment in hysterosalpingography

Hysterosalpingography is an important diagnostic method for the evaluation of the female reproductive tract involving the exposure of patients to ionizing radiation. The irradiation of ovaries is unavoidable and radiation exposure of the patient and the associated radiological risk for the foetus and born child during the period of growth should be considered, as well. The purpose of this work is to evaluate organ and patient doses and radiation risks during hysterosalpingography procedures performed in a dedicated gynecological hospital. The entrance surface air kerma was measured for a total of 31 patients during hysterosalpingography. Based on the results obtained, the radiogenic risk for hereditary effects and cancer induction was estimated. The patient dose levels are in the range of 3-15 mGy, with a median value of 10 mGy, in terms of entrance surface air kerma. Estimated median ovarian and uterus doses are 1.7 and 2.3 mGy, respectively. The risk for fatal cancer and hereditary effects is estimated to be 5.5?10-5 and 3.4 ?10-6, respectively. Although low compared to the natural incidence of genetic effects and cancer, it can be elevated in cases of prolonged or repeated procedures or procedures where the non-optimized protocol is used.

Blood Glucose and Risk of Incident and Fatal Cancer in the Metabolic Syndrome and Cancer Project (Me-Can): Analysis of Six Prospective Cohorts

Prospective studies have indicated that elevated blood glucose levels may be linked with increased cancer risk, but the strength of the association is unclear. We examined the association between blood glucose and cancer risk in a prospective study of six European cohorts. The Metabolic syndrome and Cancer project (Me-Can) includes cohorts from Norway, Austria, and Sweden; the current study included 274,126 men and 275,818 women. Mean age at baseline was 44.8 years and mean follow-up time was 10.4 years. Excluding the first year of follow-up, 18,621 men and 11,664 women were diagnosed with cancer, and 6,973 men and 3,088 women died of cancer. We used Cox regression models to calculate relative risk (RR) for glucose levels, and included adjustment for body mass index (BMI) and smoking status in the analyses. RRs were corrected for regression dilution ratio of glucose. RR (95% confidence interval) per 1 mmol/l increment of glucose for overall incident cancer was 1.05 (1.01-1.10) in men and 1.11 (1.05-1.16) in women, and corresponding RRs for fatal cancer were 1.15 (1.07-1.22) and 1.21 (1.11-1.33), respectively. Significant increases in risk among men were found for incident and fatal cancer of the liver, gallbladder, and respiratory tract, for incident thyroid cancer and multiple myeloma, and for fatal rectal cancer. In women, significant associations were found for incident and fatal cancer of the pancreas, for incident urinary bladder cancer, and for fatal cancer of the uterine corpus, cervix uteri, and stomach. Data from our study indicate that abnormal glucose metabolism, independent of BMI, is associated with an increased risk of cancer overall and at several cancer sites. Our data showed stronger associations among women than among men, and for fatal cancer compared to incident cancer. Please see later in the article for the Editors' Summary.

Assessment of Radiation Dose Rates in the High Terrestrial Gamma Radiation Area of Selama District, Perak, Malaysia

Survey of terrestrial gamma radiation (TGR) dose rates have been conducted in Selama district, Perak, Malaysia. Themean value of TGR dose rate outdoor in Selama is (273 ± 133) nGy h-1. For the habited land, the mean TGR dose ratesoutdoor and indoor are (205 ± 59) nGy h-1 and (212± 64) nGy h-1 respectively. They contribute fatal cancer risk of 6.4 x10-5 per year to an individual in the area. The activity concentrations of 238U, 232Th, and 40K in the soil samples wereanalysed using a high resolution co-axial HPGe gamma ray spectrometer system. The values obtained range from 57 Bqkg-1 to 364 Bq kg-1 with the mean value of (178±95) Bq kg-1 for 238U; 207 Bq kg-1 to 625 Bq kg-1 with the mean value of(353±143) Bq kg-1 for 232Th, and 26 Bq kg-1 to 601 Bq kg-1 with the mean values of (273±133) Bq kg-1 for 40K.

Health Risk Implications of High Background Radiation Dose Rate in Kampung Sungai Durian, Kinta District, Perak, Malaysia

Terrestrial gamma radiation dose rate measurement has been conducted around Kampung Sungai Durian (Kg. Sg.Durian), Kinta District, Malaysia. The mean value of outdoor terrestrial gamma radiation (TGR) dose rate and indoor inthe area are 458 nGy h-1 and 286 nGy h-1, respectively. It causes fatal cancer risk of about 9.90 x 10-5 per year to eachindividual. The activity concentrations of 238U, 232Th and 40K in soil samples were measured by gamma spectrometry. Itranged from 32 Bq kg-1 to 554 Bq kg-1, 64 Bq kg-1 to 1 806 Bq kg-1 and 21 Bq kg-1 to 2 522 Bq kg-1, respectively.Activity concentration of uranium and thorium ranged from

Cigarette Smoking and Prostate Cancer in a Prospective US Cohort Study

Smoking is an important risk factor for many cancers, yet the relationship between smoking and prostate cancer remains uncertain. We investigated whether smoking affected the risk of prostate cancers within a large prospective cohort study of dietary and environmental cancer risk factors among men ages 50 to 71 upon enrollment in 1995-1996 (n = 283,312). Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (95% CI) were adjusted for age, race, education, height, body mass index, physical activity, family history of prostate cancer, diabetes, self-reported health status, prostate-specific antigen testing, digital rectal exam, total energy, alpha-tocopherol, calcium, alpha-linolenic acid, selenium, red meat, fish, and tomato intake. There were 14,810 nonadvanced and 1,830 advanced incident prostate cancers identified through 2003, and 394 men died of their disease through 2005. Current smokers had a decreased risk of nonadvanced prostate cancer (HR, 0.82; 95% CI, 0.77-0.88), but an increased risk of fatal prostate cancer (HR, 1.69; 95% CI, 1.25-2.27). Former smoking was also associated with decreased risk of nonadvanced prostate cancers (HR, 0.89; 95% CI, 0.86-0.92), but not fatal prostate cancers (HR, 1.03; 95% CI, 0.83-1.27). There was no apparent association between smoking and advanced prostate cancer. A number of biologically plausible mechanisms could explain these results, including the direct effects of carcinogens in tobacco smoke and the resulting changes in sex hormone or growth factor profiles. These findings suggest that current and former smokers may be at decreased risk of being diagnosed with prostate cancer and current smokers are at an increased risk of dying from prostate cancer.

Reduction of the estimated radiation dose and associated patient risk with prospective ECG-gated 256-slice CT coronary angiography

Computed tomography (CT) coronary angiography has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but high radiation doses have been reported. Prospective ECG-gating using a ‘step-and-shoot’ axial scanning protocol has been shown to reduce radiation exposure effectively while maintaining diagnostic accuracy. 256-slice scanners with 80 mm detector coverage have been currently introduced into practice, but their impact on radiation exposure has not been adequately studied. The aim of this study was to assess radiation doses associated with CT coronary angiography using a 256-slice CT scanner. Radiation doses were estimated for 25 patients scanned with either prospective or retrospective ECG-gating. Image quality was assessed objectively in terms of mean CT attenuation at selected regions of interest on axial coronary images and subjectively by coronary segment quality scoring. It was found that radiation doses associated with prospective ECG-gating were significantly lower than retrospective ECG-gating (3.2 ± 0.6 mSv versus 13.4 ± 2.7 mSv). Consequently, the radiogenic fatal cancer risk for the patient is much lower with prospective gating (0.0176% versus 0.0737%). No statistically significant differences in image quality were observed between the two scanning protocols for both objective and subjective quality assessments. Therefore, prospective ECG-gating using a ‘step-and-shoot’ protocol that covers the cardiac anatomy in two axial acquisitions effectively reduces radiation doses in 256-slice CT coronary angiography without compromising image quality.

Smoking as a Risk Factor for Prostate Cancer: A Meta-Analysis of 24 Prospective Cohort Studies

We evaluated the relationship between smoking and adenocarcinoma of the prostate. We pooled data from 24 cohort studies enrolling 21 579 prostate cancer case participants for a general variance-based meta-analysis. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated separately for mortality and incidence studies. We tested the robustness of effect measures and evaluated statistical heterogeneity with sensitivity analyses. In the pooled data, current smokers had no increased risk of incident prostate cancer (RR = 1.04; 95% CI = 0.87, 1.24), but in data stratified by amount smoked they had statistically significant elevated risk (cigarettes per day or years: RR = 1.22; 95% CI = 1.01, 1.46; pack years of smoking: RR = 1.11; 95% CI = 1.01, 1.22). Former smokers had an increased risk (RR = 1.09; 95% CI = 1.02, 1.16). Current smokers had an increased risk of fatal prostate cancer (RR = 1.14; 95% CI = 1.06, 1.19). The heaviest smokers had a 24% to 30% greater risk of death from prostate cancer than did nonsmokers. Observational cohort studies show an association of smoking with prostate cancer incidence and mortality. Ill-defined exposure categories in many cohort studies suggest that pooled data underestimate risk.

Life course sun exposure and risk of prostate cancer: Population‐based nested case‐control study and meta‐analysis

There is currently no means of primary prevention for prostate cancer. Increased exposure to ultraviolet-radiation may be protective, but the literature is inconclusive. We investigated associations of life course exposure to sunlight with prostate cancer. The study design was a UK-wide nested case-control study, based on 1,020 prostate specific antigen-detected cases and 5,044 matched population controls and a systematic review with meta-analysis. Men with olive/brown skin (OR = 1.47; 95% CI: 1.00 to 2.17), men who burnt rarely/never (OR = 1.11; 0.95 to 1.29) and men with the lowest levels of intense sun exposure in the 2 years prior to diagnosis (OR = 1.24; 1.03 to 1.50) had an increased prostate cancer risk. However, amongst men with prostate cancer, spending less time outside was associated with a reduced risk of advanced cancer (OR = 0.49; 0.27 to 0.89) and high Gleason grade (OR = 0.62; 0.43 to 0.91), and men who burnt rarely/never had a reduced risk of advanced cancer (OR = 0.71; 0.47 to 1.08). The meta-analysis provided weak evidence that men with the lowest (versus highest) sunlight exposure had an increased prostate cancer risk (4 studies, random-effects pooled relative risk = 1.13; 0.98 to 1.29) and higher advanced or fatal prostate cancer risk (6 studies, random-effects pooled relative risk = 1.14; 0.98 to 1.33). Our data and meta-analyses provide limited support for the hypothesis that increased exposure to sunlight may reduce prostate cancer risk. The findings warrant further investigation because of their implications for vitamin D chemoprevention trials.

Smoking and aggressive prostate cancer: a review of the epidemiologic evidence

Although tobacco use has been recognized as one of the leading causes of cancer morbidity and mortality, a role of smoking in the occurrence of prostate cancer has not been established. However, evidence indicates that factors that influence the incidence of prostate cancer may differ from those that influence progression and fatality from the disease. Thus, we reviewed and summarized results from prospective cohort studies that assessed the relation between smoking and fatal prostate cancer risk, as well as epidemiological and clinical studies that focused on aggressive behavior in prostate cancer, such as poorer survival, advanced stage, or poorer differentiation at diagnosis. The majority of the prospective cohort studies showed that current smoking is associated with a moderate increase of ~30% in fatal prostate cancer risk compared to never/non-smokers. This association is likely to be an underestimate of the effect of smoking because most studies had a single assessment of smoking at baseline and long follow-up times, and the association was considerably stronger in some sub-groups of heaviest smokers, or when smoking was assessed in a relatively short period (within 10 years) prior to cancer mortality. Using aggressive behavior of prostate cancer as outcome, current smoking was associated with significantly elevated risk, ranging from around twofold to threefold or higher. Although alternative explanations, such as publication bias, residual confounding, screening bias, and the influence of smoking-related comorbidities cannot be ruled out entirely, these findings suggest that smoking is associated with aggressive behavior of prostate cancers or with a sub-group of rapidly progressing prostate cancer. Based on evidence presented in this review, cigarette smoking is likely to be a risk factor for prostate cancer progression and should be considered as a relevant exposure in prostate cancer research and prevention of mortality from this cancer.

Redundant Protective Barriers: Minimizing Operator Occupational Risk

The ubiquitous use of less invasive therapeutic angiographic procedures has created the milieu for long-term occupational risk of cancer and genetic defects. This study set out to determine the relative effectiveness of redundant radiation protective barriers and their impact on operator total-body-ionizing radiation exposure in the catheterization suite. Thermolucent dosimeter x-irradiation was measured inside and outside personal and movable protective barriers used concurrently during 50 consecutive procedures by a single operator. Additionally, the entrance/exit doses were recorded on the back and chest for all patients to provide insight into radiation scatter patterns. The x-ray beam had an average 90.8% decrement in energy traversing the patient's chest when entrance and exit doses were compared, suggesting a 3.3-fold greater operator scatter radiation exposure below the table compared with that above the table. All 0.5-mm lead equivalent personal barriers reduced operator exposure by 72-95%, whereas the 1.0-mm leaded personal barrier (overlapping gown) reduced exposure by 96%. The 0.75-mm leaded glasses reduced exposure to the left eye by 67%. A leaded left-hand glove reduced exposure by only 20%. The effective calculated operator radiation exposure risk reduction provided by the use of personal and movable barriers reduced the theoretical risk of fatal or nonfatal cancer by 22-fold while decreasing potential severe genetic effect by 25-fold in comparison to movable barriers alone. The optimal use of combined personal and movable (redundant) lead barriers results in a significant reduction in total-body operator radiation exposure in the catheterization laboratory. The use of redundant barriers in the catheterization suite is associated with a dramatic theoretical long-term occupational risk reduction and should be encouraged.

Preserved Diagnostic Performance of Dual-Source CT Coronary Angiography with Reduced Radiation Exposure and Cancer Risk

To evaluate the effects of standard and optimal electrocardiographic (ECG) pulsing on diagnostic performance, radiation dose, and cancer risk in symptomatic patients in a "real-world" clinical setting. The institutional review board approved the study, and all patients gave informed consent. Dual-source computed tomographic (CT) coronary angiography was performed in 436 symptomatic patients (301 men, 135 women; mean age, 61.6 years +/- 10.6 [standard deviation]; age range, 23-89 years) referred for conventional coronary angiography. Standard and optimal ECG pulsing was performed in 327 and 109 patients, respectively. The diagnostic performance of dual-source CT coronary angiography for detection of significant stenosis (>or=50 luminal diameter reduction), with quantitative coronary angiography as the reference standard, was reported as sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios. The mean effective radiation dose, additional fatal cancer risk, and age- and sex-specific cancer risks related to one CT coronary angiographic examination were determined from data averaged over the study population. Mean effective doses with standard and optimal ECG pulsing were 14.2 mSv +/- 3.2 and 10.7 mSv +/- 3.6, respectively. Optimal ECG pulsing resulted in a 43% overall reduction in mean effective radiation dose and cancer risk compared with a nonpulsing protocol (18.8 mSv +/- 3.5) and a 25% overall reduction in mean effective dose compared with the standard pulsing protocol. At patient-by-patient analysis, CT coronary angiography with standard ECG pulsing yielded sensitivity, specificity, and positive and negative predictive values of 100% (95% confidence interval [CI]: 99%, 100%), 85% (95% CI: 81%, 88%), 94% (95% CI: 91%, 96%), and 99% (95% CI: 98%, 100%), respectively, for detection of significant stenosis. Optimal ECG pulsing yielded similar results: Sensitivity, specificity, and positive and negative predictive values were 100% (95% CI: 100%, 100%), 88% (95% CI: 82%, 94%), 97% (95% CI: 93%, 100%), and 100%, respectively. Compared with a nonpulsing protocol, optimal ECG pulsing resulted in significant (P < .001) reductions in patient radiation dose and cancer risk (up to 55% reduction in patients with high heart rates) while preserving the diagnostic performance of dual-source CT coronary angiography.

Recommended evaluation of adrenal incidentalomas is costly, has high false-positive rates and confers a risk of fatal cancer that is similar to the risk of the adrenal lesion becoming malignant; time for a rethink?

To assess the performance of current clinical recommendations for the evaluation of an adrenal incidentaloma. DESIGN AND METHODS LITERATURE REVIEW: Electronic databases (Pubmed, Ovid and citation searches from key articles) from 1980 to 2008 were searched. Eligible studies were those deemed most applicable to the clinical scenario of a patient referred to an endocrinologist for assessment of an incidentally detected adrenal mass. Surgical series, histopathological series and oncological series were reviewed and most were excluded. The prevalence of functional and malignant lesions presenting as adrenal incidentaloma was similar to that quoted in most reviews, other than a lower incidence of adrenal carcinoma (1.9 vs 4.7%) and metastases (0.7 vs 2.3%). The development of functionality or malignancy during follow-up was rare (<1% becoming functional and 0.2% becoming malignant). During follow-up, false-positive rates of the recommended investigations are typically 50 times greater than true positive rates. The average recommended computed tomography (CT) scan follow-up exposes each patient to 23 mSv of ionising radiation, equating to a 1 in 430 to 2170 chance of causing fatal cancer. This is similar to the chance of developing adrenal malignancy during 3-year follow-up of adrenal incidentaloma. Current recommendations for evaluation of adrenal incidentaloma are likely to result in significant costs, both financial and emotional, due to high false-positive rates. The dose of radiation involved in currently recommended CT scan follow-up confers a risk of fatal cancer that is similar to the risk of the adrenal becoming malignant. This argues for a review of current guidelines.

Fish intake and the risk of fatal prostate cancer: findings from a cohort study in Japan

We investigated the relationship between the intake of fish and the risk of death from prostate cancer. Data were derived from a prospective cohort study in Japan. Fish consumption obtained from a baseline questionnaire was classified into the two categories of 'low intake' and 'high intake'. The Cox proportional hazards model was used to estimate hazard ratios (HR) and 95 % confidence intervals. Data for 5589 men aged 30-79 years were analysed. A total of twenty-one prostate cancer deaths were observed during 75 072 person-years of follow-up. Mean age at baseline study of these twenty-one subjects was 67.7 years, ranging from 47 and 79 years old. Results showed a consistent inverse association of this cancer between the high v. low intake groups. The multivariate model adjusted for potential confounding factors and some other food items showed a HR of 0.12 (95 % CI 0.05, 0.32) for the high intake group of fish consumption. These results support the hypothesis that a high intake of fish may decrease the risk of prostate cancer death. Given the paucity of studies examining the association between prostate cancer and fish consumption, particularly in Asian populations, these findings require confirmation in additional cohort studies.

Cohort Profile: The Metabolic syndrome and Cancer project (Me-Can)

Background: A large number of prospective studies have shown that overweight and diabetes are related to an increased risk of many cancers, including colorectal cancer. In contrast, diabetes has been related to a decreased risk of prostate cancer, and overweight has been related to an increased risk of fatal, but not of incident, prostate cancer. Data from studies on metabolic factors related to overweight and diabetes, and the association with cancer risk, are limited. Aim: The aim of this thesis was to study metabolic factors in relation to risk of prostate cancer (paper I and III), colorectal cancer (paper II and V), and cancer overall (paper VI). Methods: Study designs were i) case-control studies, nested within the Northern Sweden Health and Disease Cohort (paper I and II), and ii) cohort studies of the Swedish Construction Workers cohort (paper III), and the Metabolic syndrome and Cancer project (Me-Can) comprising seven European cohorts (paper V and VI). Paper IV was a descriptive paper of Me-Can. Results, prostate cancer: In paper I, increasing levels of several factors related to insulin resistance (insulin, insulin resistance index, leptin, HbA1c, and glucose) were associated with a decreased risk of overall incident prostate cancer, and the associations were stronger for non-aggressive tumours. In paper III, increasing levels of blood pressure was associated with a significant decreased risk of overall incident prostate cancer and of non-aggressive tumours. Body mass index (BMI) was significantly positively related to fatal prostate cancer. Results, colorectal cancer: In paper II, obesity, hypertension, and hyperglycaemia, were associated with an increased risk of colorectal cancer, and presence of two or three of these factors was associated with a higher risk than the presence of one single factor. In paper V, BMI was associated with a significant linear positive association with risk of colorectal cancer in men and women, and significant positive associations were also found in men for blood pressure and triglycerides. A high metabolic syndrome score, based on levels of BMI, blood pressure, glucose, cholesterol, and triglycerides, was associated with a significant increased risk of colorectal cancer in men and women. The association was stronger than for any of the factors in single, but there was no evidence of a positive interaction between these metabolic factors. Results, cancer overall: Blood glucose was significantly positively associated with risk of incident and fatal cancer overall, and at several specific sites. The associations were stronger in women than in men, and for fatal than for incident cancer. Conclusions: Results from these studies indicate that elevated blood glucose is related to an increased risk of cancer overall and at several specific sites, and further, that overweight and metabolic aberrations increase the risk of colorectal cancer in an additive way. The association with prostate cancer seems to be more complex; insulin resistance and high blood pressure were in our studies related to a decreased risk of overall incident prostate cancer and of non-aggressive tumours, whereas overweight increased the risk of fatal prostate cancer.

Limiting radiation exposure in coronary CT angiography: much can be achieved with little extra effort

Radiation dose is of concern in coronary CT angiography: a very recent international survey of 50 sites which routinely perform coronary CT angiography— the PROTECTION I study—revealed that some centers performed their scans with average effective radiation doses as high as 30 mSv [1]. However, these high doses are only one end of what is really a spectrum—in fact, a quite extreme end of that spectrum. In PROTECTION I, some sites used average dose as low as 5 mSv, and the median effective dose associated with coronary CT angiography in a total of 1,965 patients was 12 mSv. This needs to be put in perspective in several respects. First of all, other diagnostic measures also expose patients to radiation. A recent Science Advisory of the American Heart Association reported typical effective doses of 7 mSv for an invasive coronary angiogram, 15 mSv for a percutaneous coronary intervention, 9 mSv for a sestamibi 1-day stress/rest myocardial perfusion scan and 41 mSv for a thallium stress/rest myocardial perfusion scan [2]. This in no way means that the radiation exposure of coronary CTA is negligible or irrelevant, but in 2006, it was estimated that cardiac CT accounted for 1.5% of the collective CT-related radiation dose in the US population while cardiac nuclear medicine studies, of which more than 10 million were performed, accounted for about 20% of the collective CT-related radiation dose. Second, the effect of a given radiation exposure is extremely difficult to determine and it also varies tremendously, depending on who the exposed patient is. The induced lifetime cancer risk is superbly difficult to quantify. Assumptions are that an effective dose of 10 mSv increases the lifetime risk of fatal cancer by 0.5 per 1,000 individuals—while the background lifetime risk of ‘‘naturally occurring’’ cancer is 212 per 1,000 individuals (for comparison, the lifetime risk of a fatal motor vehicle accident is 12 per 1,000 individuals) [2]. Radiation effects in young patients and women are more severe than in older individuals and in men, so that protection from overly high radiation doses are most important in young individuals. In older patients, using a higher radiation dose for coronary CT angiography may be completely justified if it helps to avoid invasive coronary angiographies with the associated risk of invasive arterial access, such as bleeding. Radiation effects decrease and non radiation-related risks increase in older patients [3, 4] so that the balance may be entirely different than in younger individuals. All the same, there is absolutely no doubt that radiation exposure carries a risk, as small and difficult to quantify as it may be, and that doses should always be ‘‘as low as reasonably achievable’’. Tremendous progress has recently been made to provide low-dose Editorial Comment on 9396 (DOI: 10.1007/s10554-008-9396-z).