Cancer Risk Estimates Research Articles

Insights into the house dust-bound polycyclic aromatic hydrocarbons and their potential human health risk in Greater Cairo, Egypt

Data dealing with polycyclic aromatic hydrocarbons (PAHs) levels in settled dust of Greater Cairo houses (GCH), Egypt, and their implication on human health risk are scarce. The goal of this study was to gain insights into the characterisations of PAHs in settled dust in GCH and their associated carcinogenic and mutagenic risks. ƩPAH concentrations were 3125 and 268 ng/g in settled dust in GCH and rural houses (RH), respectively. Heavier congeners (4–6 aromatic ring PAHs) represented 86.5% (GCH) and 92% (RH) of ƩPAHs. Houses on main streets are exposed to higher levels of PAHs than those on the side streets. The main sources of PAHs in GCH and RH were vehicular emissions (pyrogenic sources) and PAHs in GCH come from local emissions and in RH from the surrounding urban cities. Results showed that the carcinogenicity of PAHs associated with dust exceeds their mutagenicity. Based on Incremental Lifetime Cancer Risk (ILCR) estimations, the order of cancer risk (CR) was as follows: urban houses (UH) > suburban houses (SUH) > RH. CR and ILCRs calculations suggest that children and adults exposed to settled dust-bound PAHs in GCH and RH have an increase in CR, as CR and ILCRs values exceeded accepted levels.

Genetic clinicians' confidence in BOADICEA comprehensive breast cancer risk estimates and counselees' psychosocial outcomes: A prospective study.

Counseling for familial breast cancer focuses on communicating the gene test result (GENE) to counselees, but risk prediction models have become more complex by including non‐genetic risk factors (NGRF) and polygenic risk scores (PRS). We examined genetic clinicians' confidence in counseling and counselees' psychosocial outcomes, using the BOADICEA risk prediction tool with different categories of risk factors as input. A prospective observational study in Dutch, French and German genetic clinics was performed including 22 clinicians, and 406 of 460 (88.3%) eligible cancer‐unaffected women at high breast cancer risk assessed at pre‐test and 350 (76.1%) at post‐test. We performed multilevel analyses accounting for the clinician, and counselees' characteristics. Overall, risk estimates category by GENE versus GENE+ NGRF, or GENE+NGRF+PRS differed in 11% and 25% of counselees, respectively. In multilevel analyses, clinicians felt less confident in counseling when the full model provided lower breast cancer risks than GENE (i.e., in 8% of cases). Older counselees expressed higher breast cancer risk perception and worries about the hereditary predisposition when the full model provided higher breast cancer risks than GENE only. Genetic clinicians appear confident with breast cancer risk comprehensive models, which seem only to affect perceptions of older counselees.

Does receiving high or low breast cancer risk estimates produce a reduction in subsequent breast cancer screening attendance? Cohort study

Risk-stratified breast cancer screening may improve the balance of screening benefits to harms.We assess a potential new harm: reduced screening attendance in women receiving below average-risk (false reassurance) or higher-risk results (screening avoidance). Following initial screening, 26,668 women in the PROCAS study received breast cancer risk estimates, with attendance recorded for two subsequent screening rounds. First-screen attendance was slightly reduced in below-average (85.6%) but not higher-risk women, compared to other women (86.4%). Second-screen attendance increased for women at higher-risk (89.2%) but not below-average, compared to other women (78.8%). Concerns about this potential harm of risk-stratified screening therefore appear unfounded.

Trace elements in imported black tea products in Iran: quantification and probabilistic health risk assessment

ABSTRACT Tea is a highly consumed beverage around the world, and many studies have indicated its health benefits. However, tea products may contain heavy metals that may cause negative health effects due to their toxicity. This study aimed to quantify the levels of copper (Cu), zinc (Zn), lead (Pb) and cadmium (Cd) in six different imported black tea brands marketed in Mashhad city, Iran. Twenty samples from each six black tea brands were obtained from the markets of Mashhad city, Iran, in 2012. Overall, the content of Cu, Zn, Pb and Cd ranged 6.81–35.21 mg/kg (mean = 15.87 mg/kg), 14.61–164.84 mg/kg (mean = 47.68 mg/kg), 0.038–1.62 mg/kg (mean = 0.72 mg/kg) and 0.006–0.19 (mean = 0.05 mg/kg), respectively. The mean concentration of Zn in brands C, E and F, the mean concentration of Pb in brand B and the mean concentration of Cd in brand E exceeded the Iranian and WHO standard levels. Additionally, the estimation of hazard index (HI) showed that there is no potential adverse health effect due to the consumption of the studied tea samples (HI < 1). In terms of HI, the brands were ordered as B > D > F > E > A > C. However, estimation of excess lifetime cancer risk (ELCR) for Pb showed that there is a significant lifetime cancer risk as a result of consuming the black tea products. but the estimation of ELCR for Cd showed no potential health risks.

The feasibility of implementing risk stratification into a national breast cancer screening programme: a focus group study investigating the perspectives of healthcare personnel responsible for delivery

BackgroundProviding women with personalized estimates of their risk of developing breast cancer, as part of routine breast cancer screening programmes, allows women at higher risk to be offered more frequent screening or drugs to reduce risk. For this to be feasible, the concept and practicalities have to be acceptable to the healthcare professionals who would put it in to practice. The present research investigated the acceptability to healthcare professionals who were responsible for the implementation of this new approach to screening in the ongoing BC-Predict study.MethodsFour focus groups were conducted with 29 healthcare professionals from a variety of professional backgrounds working within three breast screening services in north-west England. An inductive-manifest thematic analysis was conducted.ResultsOverall, healthcare professionals viewed the implementation of personalised breast cancer risk estimation as a positive step, but discussion focused on concerns. Three major themes are presented. (1) Service constraints highlights the limited capacity within current breast services and concerns about the impact of additional workload. (2) Risk communication concerns the optimal way to convey risk to women within resource constraints. (3) Accentuating inequity discusses how risk stratification could decrease screening uptake for underserved groups.ConclusionsStaff who implemented risk stratification considered it a positive addition to routine screening. They considered it essential to consider improving capacity and demands on healthcare professional time. They highlighted the need for skilled communication of risks and new pathways of care to ensure that stratification could be implemented in financially and time constrained settings without impacting negatively on women.

139P Breast cancer risk estimation (CanRisk tool) and perception in unaffected women with family history of breast cancer

Improvement of the accuracy of risk estimation is one of the most challenging goals of cancer risk assessment for women at risk of familial breast cancer (BC) without germline pathogenic variants in known susceptibility genes. Comprehensive risk prediction models such as CanRisk achieve the highest risk stratification by considering a full set of established risk factors. Our aims were: (i) to assess the difference between women´s risk perception and CanRisk-based risk prediction; and (ii) to compare CanRisk-based BC risk estimation with and without the incorporation of breast density (BD).

Extended analysis of solid cancer incidence among the Nuclear Industry Workers in the UK: 1955-2011.

Radiation worker studies provide direct estimates of cancer risk after protracted low-dose exposures to external X-ray and gamma-ray irradiations. The National Registry for Radiation Workers (NRRW) started in 1976 and has become the largest epidemiological program of research on nuclear workers in the UK. Here, we report on the relationship between solid cancer incidence and external radiation at the low-dose levels in 172,452 NRRW cohort members of whom (90%) were men. This study is based on 5.25 million person-years of follow-up from 1955 through the end of 2011. In the range of accumulated low doses two-thirds of workers have doses of less than 10 mSv. This study is an updated analysis of solid cancer incidence data with an additional 10 years of follow-up over the previous analysis of the NRRW cohort (NRRW-3). A total of 18,310 cases of solid cancers based on a 10-year lag were registered and of these 43% of the solid cancer cases occurred during the latest 10 years. Poisson regression was used to investigate the relationship between solid cancers risk and protracted chronic low-dose radiation exposure. This study demonstrated for solid cancers a rapid decrease of risk at high external doses that appeared to be driven by the workers who were monitored for potential exposure to internal emitters and who had also received relatively high external doses. Among cohort members only exposed to external radiation, a strong association was found between external dose and solid cancers (ERR/Sv = 0.52, 95% CI: 0.11; 0.96, based on 13,199 cases). A similar pattern is also seen for lung cancer. Excluding lung cancer from the grouping of all solid cancers resulted in evidence of a linear association with external radiation dose (ERR/Sv = 0.24, 95% CI: 0.01; 0.49, based on 15,035 cases), so suggesting some degree of confounding by smoking. Statistically significantly increasing trends with dose were seen for cancers of the colorectal, bladder and pleura cancer. Some of these results should be treated with caution because of the limited corroborating evidence from other published studies. Information on internal doses as well as non-radiation factors such smoking would be helpful to make more definitive inferences.

Comprehensive Evaluation of Dietary Exposure and Health Risk of Polychlorinated Naphthalenes.

Intake from food is considered an important route of human exposure to polychlorinated naphthalenes. To our knowledge, several studies have quantified dietary exposure but only in European countries and measuring only a few of the 75 congeners. In addition, the influence of source diversity on human exposure has seldom been assessed. We analyzed 192 composite food samples composed of 17,280 subsamples from 24 provinces in China to measure the concentrations of polychlorinated naphthalenes and estimate their daily intake and potential health risks on a national scale. The estimated cancer risk was in the range of 6.8 × 10-8 to 4.6 × 10-7. We compared our findings for 75 congeners with reports in the literature that quantified only 12 congeners. We estimate that these 12 congeners contribute only approximately 4% to the total mass daily intake of polychlorinated naphthalenes and 70% to the total toxic equivalent quantity, indicating underestimation of dietary exposure. The contributions of combustion-associated congeners to the total concentrations of polychlorinated naphthalenes were in the range of 31-52%, suggesting that the ongoing unintentional release of these compounds from industrial thermal processes is an important factor in polychlorinated naphthalene contamination and human exposure in China.

Impact of occupational pesticide exposure assessment method on risk estimates for prostate cancer, non-Hodgkin’s lymphoma and Parkinson’s disease: results of three meta-analyses

Assessment of occupational pesticide exposure in epidemiological studies of chronic diseases is challenging. Biomonitoring of current pesticide levels might not correlate with past exposure relevant to disease aetiology, and indirect...

Allium Vegetables Intake and Risk of Breast Cancer: A Meta-Analysis.

Background:Intake of allium vegetables may modify the risk of breast cancer. The aim of this study was to examine the association between allium vegetables intake and breast cancer risk via a meta-analysis.Methods:PubMed, Web of Knowledge, Scopus and Chinese National Knowledge Infrastructure (CNKI) were electronically searched up to June 2021 to identify relevant studies. We used random-effect models to calculate pooled risk estimates and their 95% confidence intervals (CIs) for risk of breast cancer with allium vegetables intake.Results:A total of 17 studies were included in this meta-analysis on the association of total allium vegetables, garlic and onion intake with breast cancer risk. The combined risk estimate of breast cancer for the highest vs lowest category of total allium vegetables, garlic and onion intake was 0.70 (95% CI: 0.49–0.91, P < 0.001), 0.77 (95% CI: 0.61–0.93, P = 0.016) and 0.75 (95% CI: 0.53–0.98, P < 0.001), respectively. A significant heterogeneity was found among studies for all three pooled analyses.Conclusion:High intake of allium vegetables may be protective against the development of breast cancer. Further well-designed prospective studies are needed to confirm the results.

Dermal Exposure to Hazardous Chemicals in Baby Diapers: A Re-Evaluation of the Quantitative Health Risk Assessment Conducted by The French Agency for Food, Environmental and Occupational Health and Safety (ANSES).

In January 2019, the French Agency for Food, Environmental and Occupational Health and Safety (ANSES) published an opinion on risks related to the presence of hazardous chemicals in infant diapers. ANSES found that health reference values were largely exceeded for polycyclic aromatic hydrocarbons (PAHs), dioxins (PCCD/Fs) and dioxin-like polychlorobiphenyls (DL-PCBs). The levels of formaldehyde and some fragrances were also considered potentially unsafe. Therefore, ANSES concluded that actions have to be taken to restrict levels of these contaminants in diapers. Under the exposure scenario deemed the most reliable by ANSES, estimates of cancer risks of the most potent PAHs detected in diapers exceeded 10−3 and hazard quotients for neurobehavioral effects attained values up to 66. Regarding dioxins and DL-PCBs, ANSES derived a hazard quotient of 12 for the risk of decreased sperm count at adult age. The aim of this study was to examine whether the exposure and risk assessment conducted by ANSES contained potential flaws that could explain such a high exceedance of health reference values. This study also put into perspective the exposure from diapers with that from breast milk whose benefits for children’s health are undisputable despite contamination by PAHs, dioxins and DL-PCBS.

Emissions monitoring and carcinogenic risk assessment of PM10-bounded PAHs in the air from Candiota's coal activity area, Brazil.

The city of Candiota contains a great amount of coal resources. Coal activities, including coal combustion, are major releasers of polycyclic aromatic hydrocarbons (PAHs). The PAHs are considered priority air pollutants regarding their large carcinogenic potential. So, the carcinogenic risk assessment of populations living near areas with PAH sources is mandatory. This study aimed to evaluate the carcinogenic health risk of the PAH inhalation exposure of individuals living in Candiota City. A total of 158 individuals were enrolled in the study. Monitoring of PAH and meteorological parameters were carried out, and the health risk assessment was determined through the benzo(a)pyrene equivalent toxic equivalent quotient (BaP-TEQ) and the incremental lifetime cancer risk (ILCR) estimation. The coal activity area of Candiota demonstrated an annual PAH concentration of 27.7ng/m3, PM10 concentration of 26.3µg/m3, SO2 concentration of 9.5µg/m3, a BaP-TEQ value of 0.3ng/m3, and a daily inhalation of 62.4ng/day. The comparison among seasons showed no difference in PAH concentration and BaP-TEQ. It was observed ILCR values of 2.8 × 10-6 and 2.6 × 10-6 for estimation based on reference and real values, respectively, and these levels were above the reference limit of 10-6, indicating cancer risk. Therefore, an epidemiological survey of cancer cases in the region and its relationship with environmental exposure and air pollutants levels must be required.

A software tool for organ-specific second cancer risk assessment from exposure to therapeutic doses.

The aim of this study was the development of a software tool (SCRcalc) for the automatic estimation of the patient- and organ-specific cancer risk due to radiotherapy. SCRcalc was developed using the Python 3.8.7 programming language. It incorporates equations and parameters of mechanistic models for the calculation of the organ equivalent dose (OED), the excess absolute risk (EA R) and the lifetime attributable risk (LA R) of carcinogenesis for various organs due to radiotherapy. Data from differential dose-volume histograms, as defined by a treatment planning system, could be automatically inserted into the program. Eighteen different cancer risk estimates for various organs were performed of patients subjected to radiation therapy with conventional and modulated techniques. These software estimates were compared with manual calculations. SCRcalc was developed as a standalone executable program without any dependencies. It enables direct estimations of the OED and LAR for various organs at risk. An important aspect of the software is that it does not require pre-processing of the DVH data. No differences were found between the SCRcalc results and those derived from manual calculations. The newly developed software offers the possibility to medical physicists and radiation oncologists to directly estimate the probability of radiotherapy-induced secondary malignancies for various organs at risk.

Concentrations, sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in black, green and fruit flavored tea in Turkey

This study was performed to identify the levels and possible sources of EPA priority PAHs in different types of commercially sold and consumed tea samples in Turkey. Health risk related to PAHs exposure due to tea consumption was also estimated. The average total PAH concentrations were measured as 317.0, 352.3, and 452.3 μg/kg for 25 black, three green, and 12 flavored Turkish tea samples. The results showed that 3- and 4-ring PAHs were the predominant groups for all tea samples. Factor analysis was utilized to identify the source characteristics of PAHs in tea samples. The results indicated that emissions from direct contact during transport and storage of tea leaves have significant impacts in addition to those from thermal processing during production. The estimated lifetime cancer risks ranged from 4.4 × 10−5 to 2.0 × 10−4 for all tea samples, indicating low-to-moderate risks for consumers of these tea products. All the estimated cancer risk values for PAHs in this study were higher than permissible risk levels, while three flavored tea samples were higher than the acceptable risk levels specified by US EPA.

Cancer risk estimation using American College of Radiology Thyroid Imaging Reporting and Data System for cytologically indeterminate thyroid nodules

BackgroundWe sought to determine if using the ACR TI-RADS ultrasound score combined with the Bethesda diagnosis can help augment thyroid cancer risk estimation. MethodsTI-RADS scores and Bethesda diagnoses were collected for patients treated in our center who had undergone thyroidectomy. Data from 186 patients with both TI-RADS scores and Bethesda diagnosis, and Bethesda diagnosis alone, were analyzed by multivariable regression analysis and observed for whether the pathology was benign or malignant. ResultsThe regression analysis model showed that as the TI-RADS score increases, the odds of malignancy increases as well. The predictive value of the odds of malignancy in a thyroid nodule using both Bethesda diagnosis and TI-RADS score together was more powerful than the odds given using the Bethesda diagnosis alone. ConclusionsOur model shows that the ACR TI-RADS score may assist with preoperative decision-making for patients with cytologically indeterminate thyroid nodules when combined with Bethesda diagnosis.

A comparison of Low Dose with Standard Dose Chest CT Scan in Diagnosis of COVID-19

Aim: Comparison of safety profile of low dose CT scan chest with standard dose CT scan in Covid 19. Study design: Prospective study Place and duration of study: Department of Radiology, Benazir Bhutto Hospital, Rawalpindi from -01-09-2020 to 31-03-2021. Methods After approval from ERB, 45 COVID-19 positive patients diagnosed by PCR, aged 55 years and above were selected. In the prospective study, these patients with normal CXR were advised for same day chest CT scan. Initially, a standard dose of chest CT scan of 150mAs was applied. After assessing the chest signs of Covid on scan, a low-dose CT of 30mAs was performed instantly. A comparison was made to check the diagnostic accuracy of standard-dose and low-dose CT for the identification of features of typical COVID19 pneumonia. Results: The mean age of patients was 58.27±7.23. An admirable intra-reader agreement was found between low- and standard-dose CT in identifying typical findings of COVID pneumonia (intraclass correlation coefficient [ICC] = 0.98–0.99 with A p value of less than 0.001 of all readers). Mean effective dose values of low and standard dose groups were 1.69±0.38 mSv and 7.21±1.23, correspondingly. Values of absolute cancer risk per mean cumulative effective dose of low &amp; standard dose chest CT examinations were 0.68 × 10−4 and 2.41×10−4 respectively. Conclusions: The low dose CT chest protocol is better than standard dose for the identification of typical COVID-19 pneumonia features in routine practice with substantial decrease in dose of radiation as well as estimated cancer risk. Keywords: SARS CoV 2, Diagnosis, CT scan, Safety profile

Abstract P2-11-21: Integration of an ancestrally unbiased polygenic risk score with the Tyrer-Cuzick breast cancer risk model

Abstract Background: Polygenic risk scores (PRS) have been shown to provide genomically informed breast cancer risk assessment in both carriers and non-carriers of predisposing genetic mutations. Risk stratification is further improved by combining a PRS with risk models incorporating traditional risk factors to generate a Combined Risk Score (CRS). We recently developed and validated a breast cancer PRS for women of diverse ancestries using ancestry-informative genetic markers. Here, we combine the diverse ancestry PRS with a clinical and family history-based model to develop an integrated genomically-informed and ancestrally unbiased risk assessment tool. Methods: The study sample included women in the U.S. without a personal history of breast cancer, referred for clinical genetic testing between June 2020 and March 2021, and who tested negative for pathogenic or likely pathogenic variants in breast cancer susceptibility genes. A CRS, incorporating a validated PRS and the TC model, was generated using a previously described Fixed-Stratified method that accounts for association between PRS and clinical risk factors. Association between the PRS and each clinical risk factor included in the Tyrer-Cuzick (TC) breast cancer risk model (version 7) was tested using linear regression with PRS as the dependent variable and the TC factor as an independent variable with adjustment for age and ancestry. We examined the rate of reclassification resulting from incorporation of PRS into the CRS by classifying women as having high (&amp;gt;20%) remaining lifetime risk (RLR) versus low (≤20%) RLR according to both TC and CRS. Results: Among 68,803 women, 21,500 (31.2%) had one or more first degree relatives (FDR) with breast cancer. Approximately 10% of women reported only African ancestry and a similar percentage reported only Hispanic/Latina ethnicity (Table 1). Family history was significantly associated with PRS (p=1.0x10-76). After adjusting for multiple testing, no other factors showed significant association with PRS. Improved risk stratification of CRS over TC follows from two results: (1) We previously showed that PRS improved risk stratification above and beyond family history; (2) In the present study, PRS was not associated with any TC factor other than family history. Adding the PRS to the TC model significantly altered breast cancer risk estimates for women of all ancestries, with 17.3% of patients stratified differently by CRS versus TC alone. Differences in risk stratification (using the 20% threshold) for each self-reported ancestry are presented in Table 1. The CRS classified fewer patients (32.0%) as high RLR than the TC model alone (35.4%), with similar results for 5-year risk estimates. Conclusions: This is the first genomically-informed, integrated polygenic and traditional breast cancer risk model for US women referred for contemporary clinical genetic testing. This model advances the PRS component of a previously validated combined model. It effectively estimates 5-year and lifetime risk for breast cancer using a PRS with an objectively genetically determined ancestral composition, calibrated and validated for risk stratification in all ancestries. The model may reliably and responsibly inform risk reduction strategies such as enhanced surveillance and use of preventive medications. Table 1.Self-Reported Ancestry/EthnicityNumber (%) of patientsHigh TC High CRS High TC and Low CRSLow TC and High CRSAll68,803 (100%)24,332 (35.4%)22,041 (32.0%)7,080 . (10.3%)4,789 . (7.0%)Asian1,450. (2.1%)487 (33.6%)475 (32.8%)94 . (6.5%)82 . (5.7%)African7,909 (11.5%)2,540 (32.1%)2,473 (31.3%)435 . (5.5%)368 . (4.7%)Hispanic6,481 . (9.4%)1,614 (24.9%)1,345 (20.9%)606 . (9.4%)346 . (5.3%)Non-European*19,225 (27.9%)5,701 (29.7%)5,297 (27.6%)1,429 . (7.4%)1,025 . (5.3%)European**46,640 (67.8%)17,507 (37.5%)15,733 (33.7%)5,328 . (11.4%)3,554 . (7.6%)*Includes any combination of Black/African, Middle Eastern, Pacific Islander, Asian, Hispanic/Latino and/or Native American ancestry. **Includes White/Non-Hispanic and/or Ashkenazi Jewish. Citation Format: Elisha Hughes, Ryan Bernhisel, Holly Pederson, Braden Probst, Timothy Simmons, Susanne Wagner, Thaddeus Judkins, Eric Rosenthal, Benjamin Roa, Susan M. Domchek, Charis Eng, Judy Garber, Monique Gary, Ora K. Gordon, Jennifer Klemp, Semanti Mukherjee, Kenneth Offit, Funmi Olopade, Joseph Vijai, Jeffrey N. Weitzel, Pat Whitworth, Lamis Yehia, Allison Kurian, Mark Robson, Thomas P. Slavin, Alexander Gutin, Jerry S. Lanchbury. Integration of an ancestrally unbiased polygenic risk score with the Tyrer-Cuzick breast cancer risk model [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-11-21.

Out-of-field doses in pediatric craniospinal irradiations with 3D-CRT, VMAT, and scanning proton radiotherapy: A phantom study.

Craniospinal irradiation (CSI) has greatly increased survival rates for patients with a diagnosis of medulloblastoma and other primitive neuroectodermal tumors. However, as it includes exposure of a large volume of healthy tissue to unwanted doses, there is a strong concern about the complications of the treatment, especially for the children. To estimate the risk of second cancers and other unwanted effects, out-of-field dose assessment is necessary. The purpose of this study is to evaluate and compare out-of-field doses in pediatric CSI treatment using conventional and advanced photon radiotherapy (RT) and advanced proton therapy. To our knowledge, it is the first such comparison based on in-phantom measurements. Additionally, for out-of-field doses during photon RT in this and other studies, comparisons were made using analytical modeling. In order to describe the out-of-field doses absorbed in a pediatric patient during actual clinical treatment, an anthropomorphic phantom, which mimics the 10-year-old child, was used. Photon 3D-conformal RT (3D-CRT) and two advanced, highly conformal techniques: photon volumetric-modulated arc therapy (VMAT) and active pencil beam scanning (PBS) proton RT were used for CSI treatment. Radiophotoluminescent and poly-allyl-diglycol-carbonate nuclear track detectors were used for photon and neutron dosimetry in the phantom, respectively. Out-of-field doses from neutrons were expressed in terms of dose equivalent. A two-Gaussian model was implemented for out-of-field doses during photon RT. The mean VMAT photon doses per target dose to all organs in this study were under 50% of the target dose (i.e.,<500mGy/Gy), while the mean 3D-CRT photon dose to oesophagus, gall bladder, and thyroid, exceeded that value. However, for 3D-CRT, better sparing was achieved for eyes and lungs. The mean PBS photon doses for all organs were up to three orders of magnitude lower compared to VMAT and 3D-CRT and exceeded 10mGy/Gy only for the oesophagus, intestine, and lungs. The mean neutron dose equivalent during PBS for eight organs of interest (thyroid, breasts, lungs, liver, stomach, gall bladder, bladder, prostate) ranged from 1.2mSv/Gy for bladder to 23.1 mSv/Gy for breasts. Comparison of out-of-field doses in this and other phantom studies found in the literature showed that a simple and fast two-Gaussian model for out-of-field doses as a function of distance from the field edge can be applied in a CSI using photon RT techniques. PBS is the most promising technique for out-of-field dose reduction in comparison to photon techniques. Among photon techniques, VMAT is a preferred choice for most of out-of-field organs and especially for the thyroid, while doses for eyes, breasts, and lungs are lower for 3D-CRT. For organs outside the field edge, a simple analytical model can be helpful for clinicians involved in treatment planning using photon RT but also for retrospective data analysis for cancer risk estimates and epidemiology in general.

Estimation of excess life cancer risk and annual effective dose for boreholes and well water in Dutse, Jigawa State Nigeria

The level of 222Rn concentration for water samples collected from twenty-two (22) water samples in Dutse Local Government, Jigawa State, Nigeria was determined using liquid scintillation counter (Model: Tri-CarbLSA1000). Borehole and local hand dug wells are the two sources of water been collected. Also, an attempt was made to estimate the Excess Life Cancer Risk and Annual Effective Dose due to Ingestion for different ages groups. The mean value of 222Rn concentration were found to be 82.7461 and 94.10771 BqL-1 for boreholes and well water samples respectively. All the mean values are above the maximum concentration level set by UNSCEAR; WHO, but below European commission of 100 BqL-1. The resulting mean annual effective doses due to ingestion of radon in the water samples for infants, children and adults, were1.057081 and 1.202226 mSvy-1, 0.90607 and 1.030479 mSvy-1 and 0.604047 and 0.686986 mSvy-1, respectively. Also, the resulting mean Excess life cancer risk due to ingestion in borehole and well water sample for adults, children and infants were 2.114E-3 and 2.37 E-1, 3.171 x 10-3 and 3.61 E-3 and 3.7 E-4 and 4.21 E-3 respectively. All the values were found to be above the maximum concentration level for drinking water and domestic purposes. as set by UNSCEAR, WHO, EU and USEPA. From the radiological point of view, this study indicates that water resources around Dutse Local Government Area Jigawa State were not safe for domestic purposes and drinking.

Influence of Cancer Susceptibility Gene Mutations and ABO Blood Group of Pancreatic Cancer Probands on Concomitant Risk to First-Degree Relatives.

ABO blood group is associated with pancreatic cancer risk. Whether ABO blood group alone or when combined with inherited mutation status of index pancreatic cancer cases (probands) can enhance pancreatic cancer risk estimation in first-degree relatives (FDR) is unclear. We examined FDRs' risk for pancreatic cancer based on probands' ABO blood group and probands' cancer susceptibility gene mutation status. Data on 23,739 FDRs, identified through 3,268 pancreatic cancer probands, were analyzed. Probands' ABO blood groups were determined serologically or genetically, and 20 cancer susceptibility genes were used to classify probands as "mutation-positive" or "mutation-negative." SIRs and 95% confidence intervals (CI) were calculated, comparing observed pancreatic cancer cases in the FDRs with the number expected in SEER-21 (reference population). Overall, FDRs had 2-fold risk of pancreatic cancer (SIR = 2.00; 95% CI = 1.79-2.22). Pancreatic cancer risk was higher in FDRs of mutation-positive (SIR = 3.80; 95% CI = 2.81-5.02) than mutation-negative (SIR = 1.79; 95% CI = 1.57-2.04) probands (P < 0.001). The magnitude of risk did not differ by ABO blood group alone (SIRblood-group-O = 1.57; 95% CI = 1.20-2.03, SIRnon-O = 1.83; 95% CI = 1.53-2.17; P = 0.33). Among FDRs of probands with non-O blood group, pancreatic cancer risk was higher in FDRs of mutation-positive (SIR = 3.98; 95% CI = 2.62-5.80) than mutation-negative (SIR = 1.66; 95% CI = 1.35-2.03) probands (P < 0.001), but risk magnitudes were statistically similar when probands had blood group O (SIRmutation-positive = 2.65; 95% CI = 1.09-5.47, SIRmutation-negative = 1.48; 95% CI = 1.06-5.47; P = 0.16). There is a range of pancreatic cancer risk to FDRs according to probands' germline mutation status and ABO blood group, ranging from 1.48 for FDRs of probands with blood group O and mutation-negative to 3.98 for FDRs of probands with non-O blood group and mutation-positive. Combined ABO blood group and germline mutation status of probands can inform pancreatic cancer risk estimation in FDRs.