جستجوی مقالات مرتبط با کلیدواژه "cancer risk" در نشریات گروه "پزشکی"

This study aimed to investigate the concentration of potentially toxic elements (PTEs) including iron (Fe), zinc (Zn), copper (Cu), cadmium (Cd) and lead (Pb) and determine their health risks, and evaluate the water quality of Abbas-Abad, Khako, Moradbeig Valley rivers and Ekbatan Dam inlets and bodies located in Hamadan, Iran.

In spring 2019, the concentrations of PTEs in water samples collected from 61 stations were quantified using an inductively coupled plasma optical emission spectrometry device. Water quality was evaluated using heavy metal pollution index (HPI), heavy metal evaluation index (HEI), contamination degree , heavy metal toxicity load (HMTL), and environmental water quality index (EWQI) indices. Carcinogenic and non-carcinogenic risks were calculated usingcancer risk (CR) and hazard index (HI), respectively.

It was found that the average concentration of Fe and Zn had a statistically significant difference (P < 0.05). By comparing the metal concentration to the World Health Organization’s standard, the concentrations of all elements were below the permissible limit, except for Fe and Cd, in 4 and 5 sampling stations. The quality of water sources revealed a low level of PTE contamination in the studied surface water. According to the HI results, there was no apparent threat to the residents’ health. Based on the CR assessment results, the dermal absorption of PTEs for both age groups was classified as low-risk. However, ingestion of these elements was categorized as high-risk.

Since Hamdan’s surface water sources are contaminated with PTEs, it is necessary to investigate effective management strategies for preserving the integrity and health of water resources.

miRNAs are non-coding RNAs participating actively in the post-translational regulation of oncogenes, tumor suppressor, and DNA repair genes implicated in colorectal cancer (CRC). This study aims to examine the association of the variants miR-27a (rs895819 A > G), miR-196a2 (rs11614913 T > G) and miR-146a (rs2910164 C > G) in Mexican CRC patients.

DNA samples from 183 patients and 186 healthy Mexican subjects were analyzed. Variants were identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated by the odds ratio (OR) and adjusted by the Bonferroni test.

Patients carrying the G/G genotype of the rs895819 variant in the miR-27a gene showed an increased risk of CRC (19% vs 12%, P = 0.013). A similar tendency was noticed for patients younger than 50 years carrying A/G (48% vs 41%, P = 0.014). The A/G genotype in TNM stages I + II (55.7% vs 40.8%, P = 0.011) and tumor location in the colon (69.5 vs 40.8%, P = 0.001) were also increased. For the variant rs11614913 of the miR-196a2 gene, carriers of the C/C genotype showed an increased risk of CRC (32% vs 22%, P = 0.009). This genotype was more frequent in TNM stage III + IV (36.8% vs 22.5%, P = 0.007) and the tumor had a more recurrent location in the rectum (31.6% vs 22.5%, P = 0.013). The rs2910164 variant of the miR-146a gene was found to have no significant risk associations.

Our results reveal that the rs895819 variant in miR-27a and rs11614913 in miR-196a2 have a substantial impact on the development of CRC.

Radiotherapy (RT), which is considered one of the critical treatments for cancer patients is also known as adjuvant therapy and palliative care, and can be attempted alone or concurrent with chemotherapy. Although RT reduces the risk of recurrence, the scattered dose may enhance the risk of secondary cancer induction; this is raising some challenges in clinical practice. To the best of our knowledge, few studies to date have assessed such effects of brain cancer adjuvant radiotherapy.

We estimated the RT-induced risk of secondary cancer for a 45-year-old patient who had undergone radiotherapy of the head and pelvis with a 6 MV photon beam in 15 and 10 sessions, respectively. The absorbed dose by the thyroid, breast, eye lenses, region overlying ovaries, and parotids was measured using Thermoluminescent Dosimeters (TLD). Since the patient was scanned before radiotherapy, it was decided to calculate their risk as well. To evaluate the cancer risk, radiobiological models for Excess Absolute Risk (EAR), as well as Excess Relative Risk (ERR) published by the Committee on the Biological Effects of Ionizing Radiation (BEIR) in report VII, were implemented. This study thus aimed to estimate the Risk of Exposure-Induced Death (REID) and assess the radiation dose delivered to patients from Computed Tomography (CT) scans and common diagnostic nuclear medicine examinations.

The mean risk of secondary cancer for sensitive organs was calculated 3 years after radiotherapy. The highest estimated ERR was related to the region overlying right and left ovaries for pelvic radiotherapy (47.82) and (51.17), and the next highest EAR followed by right and left eye lenses for brain radiotherapy (18.09) and (15.43), respectively. In addition, other cancers arising from CT scans had the highest REID values for solid cancer (0.0015) and bone scans revealed the highest REID values for other cancers (0.00121).

Calculating the corresponding risks of RT is of great significance for the patients in procedural change. Choosing proper field sizes and adapted techniques to avoid excessive doses to healthy organs can thus be a great assistance in this regard.

 The purpose of this study was to evaluate the risk of gonad cancer induction attributable to pelvic radiation therapy in adult patients. 

 By characterizing the peripheral dose the TLDs were placed on the testis and ovary in two fractions of radiotherapy. All patients delivered a 45 Gy total dose in 4 fields in the prone position with 3D planning. The doses from a linear accelerator at 18 MV photon beam, were investigated.

 The mean excess relative risk (ERR) based on the BEIR IIV models of men and women after 5 and 10 year of radiotherapy treatment for pelvic radiotherapy was 0.825±0.168, 0.948±0.504, 0.700±0.135, and 0.803±0.407 respectively.

 Estimating the second cancer risk of untargeted organs is crucial in radiotherapy. Using the single-energy mode linear accelerator and proper shields can be minimized the out-of-field doses.

The danger of radiation at low doses continues linearly, and without a threshold, investigations concluded that although the risk of cancer from Computed Tomography (CT) scans is low, it is not zero. This study aims to determine the patient's radiation dose and estimate the Lifetime Attributable Risk (LAR) of cancer incidence for a single chest CT scan in children

We divided 1,105 children into four age groups: 0 years, 5 years, 10 years, and 15 years. Dosimetric data of chest CT scan were plugged in VirtualDoseCT software, and organ dose and effective dose were calculated. The cancer risk based on organ dose is estimated according to the BEIR VII report.

The highest dose in boys was related to lung (5.13 - 6.8 mSv) and heart (5.27-5.97 mSv), and in girls, lung (4.98 - 5.91 mSv), breast (4.24 - 5.21 mSv), and heart (4.9 - 5.71 mSv) had the highest dose. The highest LAR (per 100,000) was obtained for the breast in the age group of 0 years (61.01), followed by the breast for the age group of 5 years (46.16) and lung in the age group of 0 years (43.32) in girls.

This study shows a better concept of radiation dose in the chest CT scan in children and how much effective dose and organ dose values increase the cancer risk.

The present research addressed the spatiotemporal variations in such pollutants as benzene, toluene, ethylbenzene, and xylene (BTEX) in the atmosphere of Arak, a city in central Iran. Also, the health risk evaluation and ozone formation potential (OFP) were assessed.

The air samples were collected and evaluated through gas chromatography-mass spectrometry (GC-MS) over a one-year period.

The overall BTEX levels ranged between 2.7-256 µgr/m3. The seasonal levels showed considerable variations among benzene, toluene, ethylbenzene, and xylene, and the levels of total BTEX. Comparison of the air samples between morning and evening for the concentrations of BTEX components revealed that the values were higher in the evening; however, there were no significant differences observed among them. The spatial map indicated that the maximal concentration of BTEX components occurred in high-traffic zones of the city. The maximal and minimal OFP levels were recorded in the summer (254.8 µgr/m3) and autumn (64.9 µgr/m3), respectively. The average toluene/benzene (T/B) ratio found to be 4.3, indicating the fuel combustion was the major source of atmospheric BTEX from vehicles.

The measured cancer risk value for benzene (6.68×10-5) was higher than those recommended by the WHO and U.S. Environmental Protection Agency. Therefore, exposure to atmospheric benzene had a carcinogenic risk for Arak inhabitants.  This needs further investigation in future studies. The acceptable hazard quotients (<1) for all BTEX species posed minimal risks of non-cancer diseases for the population.

Radionuclide ingestion has raised a global concern due to its radiological implication on man.

Activity concentration of natural radionuclides (226Ra, 232Th and 40K) in soil, leaf and fruit samples of mango plants from Akure, Nigeria has been estimated using gamma ray spectrometer NaI (Tl) detector. Spectra analyses were performed with the Genie2K spectrometry software, version 2.1 (Canberra industries Inc).

The mean activities concentration of 40K, 226Ra and 232Th in soils were 469.72 ± 86.44, 25.17 ± 9.87 and 19.33 ± 6.98 Bq kg-1 respectively. The mean activities concentration of 40K, 226Ra and 232Th in leaves were 444.76 ± 89.10, 20.43 ± 7.47 and 17.23 ± 7.39 Bq kg-1 respectively. The mean activities concentration of 40K, 226Ra and 232Th in fruits were 439.54 ± 87.39, 18.96 ± 6.80 and 15.43 ± 5.64 Bq kg-1 respectively. The mean total absorbed dose rate in air and the mean annual effective dose equivalent for soil sample were estimated at 39.37 ± 11.43 nGy h-1 and 48.28 ± 14.01 µSv y-1.

The mean radium equivalent, hazard indices and excess lifetime cancer risks (ELCR) through soil exposures are below the world average, but the mean annual effective dose equivalent and ELCR for different age groups, from radionuclide ingestion through mango consumption in the area are above the world average.

The increasing frequency of computed tomography (CT) scans for a range of purposes, particularly pediatrics, has raised concerns regarding the population's radiation exposure and subsequent chances of cancers. This study aimed to estimate the effective doses of pediatrics radiation and induced cancer risks from five most common CT scan procedures in Yazd Province, Iran.

Data of pediatric patients from four age groups of ≤1, 1-5, 5-10, and 10-15 years old were retrospectively collected from 6 educational institutions located in diverse areas of Yazd Province. For each participant, the effective doses and REID (risk of exposure-induced death) rate were estimated by Impact Dose and PCXMC software, respectively. Then, the findings were reported by categorizing the patients regarding their effective diameter.

The effective doses and REID values did not show any significant differences among the studied age groups. The highest mean of effective dose was recorded for the scan of abdomen-pelvis (average ± standard deviation, 5.24±3.19 mSv) followed by chest (3.76±2.28 mSv), brain (1.25±1.07 mSv), and sinus (0.65±0.4 mSv) examinations. The highest REID was documented for chest scan (490±314 excess deaths in one million scans) followed by abdomen-pelvis procedure (404±280).

The radiation doses delivered to the pediatric patients and the associated fatal cancer risk with common CT procedures were comparably in the same range of the previous studies. Our findings can represent an estimation of the radiation-induced risks of CT scans and can be used for extending the knowledge of clinicians and researchers.

Despite significant diagnosis benefits, the usage of ionizing radiation is not risk-free. The aim of this study was to determine the risk of thyroid cancer for children who exposed to brain computed tomography (CT) scan.
In this cross-sectional study, 90 patients under 20 years of age who underwent brain CT-scan were selected. Parameters such as age, sex, imaging technique, imaging characteristics, and thyroid absorbed dose were considered. We used SPSS software, version 21, at 95% confidence interval to analyze the absorbed dose and risk for each individual.
The mean and standard deviation of absorbed doses for girls and boys for the spiral technique were 3.954±0.393 and 4.72±0.000 mGy, and in sequential technique, were 2.282±0.461 and 1.985±0.431 mGy, respectively. The mean and standard deviation of the absorbed doses in <5 years age group were 5.65±2.00, 3.03±1.34 in 6 to 10 years, 2.63±0.98 in 11 to 15 years, and in 16 to 20 years were 2.57±1.04 mGy (P < 0.001). There was a significant negative correlation between the absorbed dose and field dimensions (r = -0.604, P < 0.001) and slice thickness (r = -0.777, P < 0.001). The mean and standard deviation of Lifetime risk for thyroid cancer induction (×105) in <5 years age group in spiral technique was 158.79±322.50 for female subjects and 16.5±42.90 for male patients, which was significantly more than those of other groups and techniques (P < 0.001).
The rate of thyroid absorbed dose during brain CT-scan was found to be noticeable, especially in spiral CT imaging, for female patients < 5 years. Based on our results, it was associated with an increased risk of thyroid cancer in this age group.

This study aimed to investigate the concentrations of heavy metals bound to airborne particulate matter (PM) in high-traffic districts of Tehran and to determine the carcinogenic risk and hazard quotient (HQ) of these metals through a descriptive-applied method.

Six indoor/outdoor stations were established in three high-traffic districts. Each station was sampled (n = 36) with six replicates in winter 2018. After extraction of the metals from fiberglass filters by acid digestion based on the ASTM method, the concentrations of heavy metals were determined by inductively coupled plasma (ICP-OES) device. The human health risk was evaluated according to the U.S. EPA standard method. Data were analyzed by SPSS software using Spearman correlation and multivariate analysis of variance (MANOVA).

Districts 2, 3, and 15 were the most high-traffic areas of Tehran, respectively. Average heavy metal concentrations were in order of Al > Fe > Pb > Mn > Cu > Zn > Cr > As > Ni > Cd, which were significantly different in indoor and outdoor environments. The correlations between heavy metal concentrations, carcinogenic risk, and HQ were significant in all three districts (p<0.05). Mean carcinogenic risk variables, HQ levels, and heavy metal concentrations in all three regions were in the order of districts 15 > 2 > 3, and outdoors > indoors.

Based on the results, serious measures are recommended to control traffic congestion in Tehran for the prevention of cancer risk and other health hazards caused by heavy metal bonded TSP (Total Suspended Particulate Matter).

Since the radionuclides concentration in teeth is a good indicator of the human body’s radioactive contamination, the purpose of this study was to measure the track density of alpha particles emitted from the human teeth and to assess the resulting cancer risk.

In this cross-section study, 93 permanent and unfilled tooth samples were collected from the patients residing in Khorramabad, Iran, and visiting dental clinics in this city. The alpha track density for the tooth samples was measured using CR-39 nuclear track detector. Annual effective dose (AED) and excess lifetime cancer risk (ELCR) were estimated based on the recommendations made by ICRP and UNSCEAR.

The mean alpha track density from 222Rn in patients’ teeth was410.15 tracks cm-2, whereas the mean for women and men equaled 441.42 and 378.20, respectively. This difference was not statistically significant (P=0.22), but there was a statistically significant difference between the track densities in different age groups (P˂0.001).In this study, the average radon activity concentration was 40.62 Bq m-3. Also, the mean annual effective dose and the mean ELCR were calculated as 1.02 mSvy-1 and 3.59 ×10-3, respectively.

The AED value was higher than the permissible dose limit and also the mean ELCR was higher than the global average. Based on the results, it is necessary to perform periodical monitoring to detect pollution sources.

The field of physician health is gaining increasing attention; however, most research and interventions have concentrated on factors such as job stress, mental health, and substance abuse. The risks of major cancers in physicians remain unclear. We used a propensity score-matched analysis to investigate the risk of cancer in physicians relative to the general population who had no healthcare-related professional background.

Data were obtained from the National Health Insurance system in Taiwan. The physician cohort contained 29,713 physicians, and each physician was propensity score-matched with a person from the general population.

The physicians demonstrated a 0.90-fold lower risk of all-cancers (95% confidence interval [CI] = 0.83 – 0.96) when compared with the general population. Female physicians had a higher risk of cancer than male physicians (adjusted hazard ratio [HR] = 1.59; 95% CI = 1.28 – 1.96). Physicians had higher risks of prostate (HR = 1.26; 95% CI = 1.00 – 1.59) and thyroid cancers (HR = 3.16; 95% CI = 1.69 – 5.90) when compared with the general population.

Physicians have lower rates of overall cancer risk than the general population. Female physicians have higher cancer risks than male physicians. Male physicians have higher risks of thyroid and prostate cancer relative to the general population.

The aim of this study was to estimate the cancer risks and mortalities of different types induced by routine examinations of digital radiography for one year in Mazandaran province, Iran.

Radiation parameters and calculated entrance skin dose (ESD) values of 13 digital radiographic examinations were collected from 2340 patients at 18 high-patient-load radiography centers. Organ mean doses were estimated based on the collected parameters applying PCXMC software. The BEIR VII-Phase 2 model was used to calculate the induced cancer risks and mortalities of various cancer types at different ages.

The average ± standard deviation (SD) lifetime risks (incidence probability in 100,000 people) induced by radiations from radiography examinations for one year was 51.29±4.73 and 99.62±7.36 for new-born males and females, respectively. The lifetime cancer risk decreased with age and reached 3.77±0.62 and 4.88±0.07 for 80-year men and women, respectively. The average lifetime risks of mortality due to cancers induced by annual radiographies were obtained at 14.18±1.62 and 22.83±2.55 for new-born males and females, respectively. This risk reduced with age and was reached 1.97±0.27 and 2.45±0.38 for men and women at the age of 80 years, respectively.

Our results showed that there are low but significant risks of cancer incidence for patients undergoing digital radiography, which included a large percentage of the population in Mazandaran province, especially for children and newborns. Therefore, further efforts like appropriate patient setup and beam geometry should be carried out to decrease patient doses.

This study aimed to estimate and compare the absorbed dose, lifetime cancer risk and mortalities due to cone-beam computed tomography (CBCT) and panoramic examinations on patients.

The exposure factors were applied to 332 patients in two age groups (6-10, and ˃18-year-old). The dose-area product (DAP) values were measured for CBCT and panoramic radiographies. Organ absorbed doses and effective doses were calculated based on the collected parameters applying PCXMC software. The risk of exposure-induced death (REID) and cancer risks were estimated by BEIR VII phase 2 model at different age groups and genders for the two dental radiography modalities.

Salivary glands was the largest contribution of the organ absorbed dose and effective dose in both CBCT and panoramic radiographies. The mean (±SD) REID values (per ten million) in CBCT were obtained at 35.6±5.2 for females and 29.01±1.8 for males, in the pediatric group, and were 31.1±2.2 for females and 25.71±2.02 for males in the adult group for all cancers. In addition, these values for panoramic radiography were 10.2±1.2 and 6.61±1.2 for women and men, respectively, in the pediatric group, and were 5.3±1.06 and 3.01±1.12 in the adult group. The mean REID values were higher significantly in CBCT compared to panoramic, and also in the pediatric than adult groups (p˂0.05).

CBCT had a significantly higher level of radiation risks compared to panoramic radiography. Therefore, clinicians should request CBCT examinations by considering their determents and benefits.