Tag: cancer risk

Cancer Risk from CT Scans up to Four Times Higher than Previous Estimates

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Computed tomography (CT) scans may account for 5% of all cancers annually, according to a new study out of UC San Francisco that cautions against overusing and overdosing CTs. For children, the greatest risk comes from scans of the head.

The danger is greatest for infants, followed by children and adolescents. But adults are also at risk, since they are the most likely to get scans. In the U.S., nearly 103 000 cancers are predicted to result from the 93 million CT scans that were performed in 2023 alone. This is 3 to 4 times more than previous assessments, the authors said.

“CT can save lives, but its potential harms are often overlooked,” said first author Rebecca Smith-Bindman, MD, a UCSF radiologist and professor of epidemiology and biostatistics and obstetrics, gynaecology and reproductive sciences.

“Given the large volume of CT use in the United States, many cancers could occur in the future if current practices don’t change,” said Smith-Bindman.

“Our estimates put CT on par with other significant risk factors, such as alcohol consumption and excess body weight,” she said. “Reducing the number of scans and reducing doses per scan would save lives.”

Benefits and potential dangers

CT is both indispensable and widely used to detect tumours and diagnose many illnesses. Since 2007, the number of annual CT exams has surged by 30% in the U.S. But the ionising radiation dose from CT is a known cancer risk.

To assess the public health impact of current CT use, the study estimates the total number of lifetime cancers associated with radiation exposure in relation to the number and type of CT scans performed in 2023.

“Our approach used more accurate and individualised CT dose and utilisation data than prior studies, allowing us to produce more precise estimates of the number of radiation-induced cancers,” said co-author Diana Miglioretti, PhD, a breast cancer researcher and division chief of biostatistics at UC Davis. “These updated estimates suggest the excess risks – particularly among the youngest children – are higher than previously recognised.”

Researchers analysed 93 million exams from 61.5 million patients in the U.S. The number of scans increased with age, peaking in adults between 60 to 69 years old. Children accounted for 4.2% of the scans. The researchers excluded testing in the last year of a patient’s life because it was unlikely to lead to cancer.

Future cancers from radiation exposure

Adults 50 to 59 had the highest number of projected cancers: 10 400 cases for women, 9300 for men. The most common adult cancers were lung, colon, leukaemia, bladder and breast. The most frequently projected cancers in children were thyroid, lung and breast.

The largest number of cancers in adults would come from CTs of the abdomen and pelvis, while in children they came from CTs of the head. Projected cancer risks were highest among those who underwent CT when they were under 1 year old. They were 10 times more likely to get cancer compared to others in the study.

The researchers said some CT scans are unlikely to help patients, and are overused, such as those for upper respiratory infections or for headaches without concerning signs or symptoms. They said patients could lower their risk by getting fewer of these scans or by getting lower dose scans.

“There is currently unacceptable variation in the doses used for CT, with some patients receiving excessive doses,” Smith-Bindman said.

Co-author Malini Mahendra, MD, a UCSF assistant professor of Pediatric Critical Care, said it was important that families understand the risk of developing cancer from paediatric scans.

“Few patients and their families are counselled about the risk associated with CT examinations,” she said. “We hope our study’s findings will help clinicians better quantify and communicate these cancer risks, allowing for more informed conversations when weighing the benefits and risks of CT exams.”

Source: University of California – San Francisco

Is Red Wine a Healthier Choice than White Wine? Uncorking the Cancer Risks

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Epidemiologists in the School of Public Health conducted a meta-analysis to assess whether red wine protects against cancer, comparing the cancer risks of red wine vs. white wine. It is published in the journal Nutrients.

Alcohol – specifically, the ethanol in alcoholic beverages – metabolises into compounds that damage DNA and proteins, contributing to cancer risk. In 2020, excessive alcohol consumption was linked to more than 740 000 cancer cases worldwide, accounting for 4.1% of all cases.

Despite the classification of alcoholic beverages as Group 1 carcinogens, meaning they are carcinogenic to humans, a common perception is that not all alcoholic beverages are alike. Red wine, in particular, is often considered a healthier choice, and its consumption is on the rise. The popularity of red wine may stem from the widespread belief that its high resveratrol content, an antioxidant with anti-inflammatory properties, offers protective effects against cancer.

Researchers from the Brown University School of Public Health have conducted a study that scours “the vast and often contradictory literature on the carcinogenicity of red and white wine” to assess whether this assumption holds up, and to compare the cancer risks associated with wine type.

“In an effort to better understand the potential impact of wine consumption on cancer risk, we conducted a comprehensive meta-analysis to assess whether red wine is truly a healthier choice than white wine,” said Eunyoung Cho, co-lead author of the study and associate professor of epidemiology and of dermatology at Brown. “Our analysis included as many published epidemiological studies as possible that separately explored the relationship between red and white wine consumption and cancer risk.”

Analyzing 42 observational studies (20 cohort and 22 case-control) involving nearly 96,000 participants, Cho and her team found no overall increased cancer risk from wine consumption, regardless of type. However, they also found no clear evidence that red wine mitigates cancer risk.

Paradoxically, when focusing on cohort studies that follow participants over a long period of time, researchers found that white wine is associated with a 22% increased risk of skin cancer compared to red wine intake.

“The results of our meta-analysis revealed no significant difference in cancer risk between red and white wine overall,” Cho said. “However, we did observe a distinction when it came to skin cancer risk. Specifically, the consumption of white wine, but not red wine, was associated with an increased risk of skin cancer.”

The reasons for this are indeterminate. Researchers suggest that heavy consumption of wine may correlate to high-risk behaviors, such as indoor tanning and inadequate sunscreen use. However, it is unclear why white wine, in particular, is the culprit. 

In an additional twist, the study also found a stronger association between white wine intake and increased overall cancer risk among women. This finding warrants further investigations into potential underlying mechanisms.

The meta-analysis, the first study of its kind, challenges the belief that red wine is healthier than white. It also points to the need for further study into the association between white wine consumption and cancer risk, particularly in women.

Source: Brown University

MS Associated with an Increased Risk of Certain Cancers

This is a pseudo-coloured image of high-resolution gradient-echo MRI scan of a fixed cerebral hemisphere from a person with multiple sclerosis.

Credit: Govind Bhagavatheeshwaran, Daniel Reich, National Institute of Neurological Disorders and Stroke, National Institutes of Health

A new study has found some cancers to be slightly more frequent in people with multiple sclerosis (MS) than in people without MS. The study is published online in Neurology®, the medical journal of the American Academy of Neurology. Types of cancers found to have a small increased risk include bladder, brain and cervical cancers.

“People with MS undergo an increased number of tests to monitor MS, making it more likely to detect other diseases,” said study author Emmanuelle Leray, PhD, of Rennes University in France. “We found an association between some types of cancer and MS which may have different explanations depending on a person’s age and the types of cancer. Overall, our study found the increased risk of cancer was quite small.”

For the study, researchers reviewed 10 years of data in the French national health care database. Researchers identified 140 649 people with MS and matched them for factors such as age, sex and residence to 562 596 people without MS. All participants were cancer free three years before the study. They were followed for an average of eight years.

During the study, 8,368 people with MS and 31,796 people without MS developed cancer.

Researchers determined there were 799 cancers per 100 000 person-years for people with MS and 736 cancers per 100 000 person-years for people without MS. Person-years represent both the number of people in the study and the amount of time each person spends in the study.

Researchers found people with MS had a 6% increased risk of developing any type of cancer regardless of age, sex and residence. They also found cancer risk was higher in those under 55 and lower in people 65 and older when compared to people without MS.

Researchers then looked at cancer types. People with MS had a 71% increased risk for bladder cancer, a 68% increased risk for brain cancer and a 24% increased risk for cervical cancer. However, they also had a 20% lower risk of prostate cancer, a 10% lower risk of colorectal cancer and a 9% lower risk of breast cancer.

“While our study found a higher risk for brain cancer, it may be due in part to earlier detection in those with MS since they regularly have brain scans which may detect cancers earlier, before a person has symptoms,” said Leray. “Frequent urinary tract infections in people with MS and the use of immunosuppressant drugs may contribute to their higher risk of bladder and cervical cancers.”

Leray added, “The lower risk for colorectal and breast cancers may be due in part to fewer people with MS getting screened for cancer in older age when they may be experiencing more MS symptoms. More research is needed, including studies that look at more closely at how cancer screenings may play a role.”

A limitation of the study was that researchers were unable to adjust for factors such as education, income, smoking and alcohol consumption since this information was not available in the national database.

Source: American Academy of Neurology

Worsening Metabolic Syndrome Exacerbates Cancer Risk

Study reveals a significant link, suggesting that managing metabolic syndrome may help prevent cancer.

Source: Pixabay CC0

New research indicates that individuals with persistent and worsening metabolic syndrome – which encompasses conditions such as high blood pressure, elevated blood sugar, excess abdominal fat, and abnormal cholesterol – face an elevated risk of developing various types of cancer. The findings are published by Wiley online in CANCER, a peer-reviewed journal of the American Cancer Society.

In the study, 44 115 adults in China with an average age of 49 years were categorised into 4 different trajectories based on trends from 2006 (the time of the first physical exam) to 2010: 10.56% exhibited a low-stable pattern and maintained low metabolic syndrome scores; 40.84% exhibited a moderate-low pattern and maintained moderate to low metabolic syndrome scores; 41.46% exhibited a moderate-high pattern and consistently maintained moderate to high metabolic syndrome scores; and 7.14% exhibited an elevated-increasing pattern in which initially elevated metabolic syndrome scores increased over time.

During the follow-up period of 2010–2021, with a median follow-up of 9.4 years, there were 2271 cancer diagnoses among participants. Compared with participants with a low-stable trajectory pattern, those with an elevated-increasing trajectory pattern had 1.3-, 2.1-, 3.3-, 4.5-, 2.5-, and 1.6-times higher risks of developing any cancer, breast cancer, endometrial cancer, kidney cancer, colorectal cancer, and liver cancer, respectively.

Even when the low-stable, moderate-low, and moderate-high trajectory pattern groups were combined, the elevated-increasing trajectory pattern group had higher risks of developing all cancer types.

Also, participants with persistently high metabolic syndrome scores and concurrent chronic inflammation had the highest risks of developing breast, endometrial, colon, and liver cancer, whereas the risk of kidney cancer was predominantly observed among participants with persistently high scores but without chronic inflammation.

“This research suggests that proactive and continuous management of metabolic syndrome may serve as an essential strategy in preventing cancer,” said senior author Han-Ping Shi, MD, PhD, of Capital Medical University, in Beijing. “Our study can guide future research into the biological mechanisms linking metabolic syndrome to cancer, potentially resulting in targeted treatments or preventive strategies. Formal evaluation of these interventions will be needed to determine if they are able to modulate cancer risk.” 

Source: Wiley