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Risk projection methods allow for timely assessment of the potential magnitude of radiation-related cancer risks following low-dose radiation exposures. The estimation of such risks directly through observational studies would generally require infeasibly large studies and long-term follow-up to achieve reasonable statistical power. We developed an online radiation risk assessment tool (RadRAT) which can be used to estimate the lifetime risk of radiation-related cancer with uncertainty intervals following a user-specified exposure history (https://irep.nci.nih.gov/radrat). The uncertainty intervals constitute a key component of the program because of the various assumptions that are involved in such calculations. The risk models used in RadRAT are broadly based on those developed by the BEIR VII committee for estimating lifetime risk following low-dose radiation exposure of the US population for eleven site-specific cancers. We developed new risk models for seven additional cancer sites, oral, oesophagus, gallbladder, pancreas, rectum, kidney and brain/central nervous system (CNS) cancers, using data from Japanese atomic bomb survivors. The lifetime risk estimates are slightly higher for RadRAT than for BEIR VII across all exposure ages mostly because the weighting of the excess relative risk and excess absolute risk models was conducted on an arithmetic rather than a logarithmic scale. The calculator can be used to estimate lifetime cancer risk from both uniform and non-uniform doses that are acute or chronic. It is most appropriate for low-LET radiation doses <1 Gy, and for individuals with life-expectancy and cancer rates similar to the general population in the US. [ABSTRACT FROM AUTHOR]

The article presents a study on computed tomography (CT) which aims to identify radiation dose and its associated potential cancer risk. It uses cross-sectional method in analyzing radiation dose among the types of diagnostic CT in patients and identifies the risk of cancer from measured doses. It finds that there is greater possibility of developing cancer after CT scan in women than in men. Moreover, it suggests standardization of CT scan in health institutions.

The article focuses on the study that reviews the protocols for coronary artery calcification (CAC) screening using multidetector computed tomography (MDCT) to calculate organ-specific radiation doses. It notes the use of Monte Carlo radiation transport to estimate the radiation doses delivered to adult patients. It cites the findings on the radiation doses and concludes that doses and radiation-induced cancer risks can be minimized using optimized protocols.

Smoking and diabetes are the only established risk factors for pancreatic cancer. Findings from recent studies suggest that obesity may also be associated with an increased risk of pancreatic cancer, but several earlier studies were less conclusive. We examined this relationship in a meta-analysis of published data. Six case-control and eight cohort studies involving 6391 cases of pancreatic cancer were identified from a computer-based literature search from 1966 to 2003. The relative risk per unit increase in body mass index was estimated for each of the studies from the published data. In a random effects model, the summary relative risk per unit increase in body mass index was 1.02 (95% CI: 1.01-1.03). There was some evidence of heterogeneity between the studies' results (P = 0.1). The summary relative risk estimates were slightly higher for studies that had adjusted for smoking and for case-control studies that had not used proxy respondents. The estimated per unit increase in body mass index would translate into a relative risk of 1.19 (95% CI: 1.10-1.29) for obese people (30 kgm[SUP-2]) compared to people with a normal body weight (22 kg m[SUP-2]). These results provide evidence that the risk of pancreatic cancer may be weakly associated with obesity. However, the small magnitude of the summary risk means the possibility of confounding cannot be excluded. [ABSTRACT FROM AUTHOR]

The article presents the results of a study on the link between cervical cancer and hormonal contraceptives. The International Agency for Research on Cancer says that combined oral contraceptives are a cause of cervical cancer but because the incidence of cervical cancer increases with age, long after the use of oral contraceptives has ceased by women, the authors sought to see if the effects of oral contraceptives can last that long in a body. The analyzing of data from 24 world wide studies showed that the risk of cervical cancer did increase in current users of oral contraceptives but declines after the woman ceases taking them. Ten years of oral contraceptive use appears to increase the risk of cancer by the age of 50.

Summary: Background: Human papillomavirus (HPV) is believed to be the most important cause of cervical cancer. Recent studies suggest that long duration use of oral contraceptives increases the risk of cervical cancer in HPV positive women. Methods: Results from published studies were combined to examine the relationship between invasive and in situ cervical cancer and duration and recency of use of hormonal contraceptives, with particular attention to HPV infection. Findings: 28 eligible studies were identified, together including 12 531 women with cervical cancer. Compared with never users of oral contraceptives, the relative risks of cervical cancer increased with increasing duration of use: for durations of approximately less than 5 years, 5-9 years, and 10 or more years, respectively, the summary relative risks were 1.1 (95% CI 1.1-1.2), 1.6 (1.4-1.7), and 2.2 (1.9-2.4) for all women; and 0.9 (0.7-1.2), 1.3 (1.0-1.9), and 2.5 (1.6-3.9) for HPV positive women. The results were broadly similar for invasive and in situ cervical cancers, for squamous cell and adenocarcinoma, and in studies that adjusted for HPV status, number of sexual partners, cervical screening, smoking, or use of barrier contraceptives. The limited available data suggest that the relative risk of cervical cancer may decrease after use of oral contraceptives ceases. However, study designs varied and there was some heterogeneity between study results. Interpretation: Although long duration use of hormonal contraceptives is associated with an increased risk of cervical cancer, the public health implications of these findings depend largely on the extent to which the observed associations remain long after use of hormonal contraceptives has ceased, and this cannot be evaluated properly from published data. [ABSTRACT FROM AUTHOR]