Radiation from Medical Imaging May Increase Cancer Rates

Medical imaging techniques that use high doses of radiation, including computed tomography (CT) scans, play an important role in modern medicine, including cancer screening. However, these procedures may themselves increase the incidence of cancer. Radiation exposure from medical imaging in the U.S. has increased more than sixfold between the 1980s and 2006. Several studies have linked multiple CT scans to increased cancer risk. Moreover, there are no official guidelines on the correct radiation doses for different medical imaging techniques, meaning that doses at one hospital may be up to 50 times higher than at another. Clear standards are needed to ensure that high-radiation imaging techniques are only used when clearly medically necessary and that the lowest feasible radiation doses are employed.


Radiation from Medical Imaging May Increase Cancer Rates

Medical imaging techniques that use high doses of radiation, including computed tomography (CT) scans, play an important role in modern medicine, including cancer screening. However, these procedures may themselves increase the incidence of cancer. Radiation exposure from medical imaging in the U.S. has increased more than sixfold between the 1980s and 2006. Several studies have linked multiple CT scans to increased cancer risk. Moreover, there are no official guidelines on the correct radiation doses for different medical imaging techniques, meaning that doses at one hospital may be up to 50 times higher than at another. Clear standards are needed to ensure that high-radiation imaging techniques are only used when clearly medically necessary and that the lowest feasible radiation doses are employed.


Radiation from Medical Imaging May Increase Cancer Rates

Medical imaging techniques that use high doses of radiation, including computed tomography (CT) scans, play an important role in modern medicine, including cancer screening. However, these procedures may themselves increase the incidence of cancer. Radiation exposure from medical imaging in the U.S. has increased more than sixfold between the 1980s and 2006. Several studies have linked multiple CT scans to increased cancer risk. Moreover, there are no official guidelines on the correct radiation doses for different medical imaging techniques, meaning that doses at one hospital may be up to 50 times higher than at another. Clear standards are needed to ensure that high-radiation imaging techniques are only used when clearly medically necessary and that the lowest feasible radiation doses are employed.


Breath Test May Help Detect Lung Cancer

A new breath test may offer a noninvasive way to detect lung cancer, even in the early stages. In a recent study, researchers analyzed the breath of patients who had either early stage lung cancer or noncancerous lung growths. They assessed the levels of four carbonyls (a type of organic chemical) in the breath. Ninety-five percent of patients with elevated levels of three or four carbonyls had lung cancer, while 80% of patients without elevated carbonyl levels were cancer-free. When lung cancer was surgically removed, carbonyl levels dropped to normal. By following up on computed tomography (CT) scan findings with this breath test, patients without cancerous growths may be able to avoid invasive biopsies, while those with cancer could progress directly to surgery.


MSC Lung Cancer Test Offers Fewer False Positives, Early Detection

Low-dose computed tomography (CT) scans are the currently recommended screening method for lung cancer in heavy smokers. However, these scans produce many false positives (identifying suspicious lung nodules when no cancer is actually present), needlessly exposing numerous people to the costs and risks of invasive follow-up procedures. Now, a large study has shown that a simple blood test may complement CT scans to reduce the false positive rate in lung cancer screening. The microRNA signature classifier (MSC) Lung Cancer assay measures the expression levels of several molecules called microRNAs to classify patients as low, intermediate, and high risk. In a trial of over 4,000 current or former smokers, the MSC Lung Cancer assay detected the vast majority of all lung cancers accurately, but produced a low rate of false positives. Moreover, the test detected some cancers up to 2 years before the CT scans.


Annual Lung Cancer Screening Recommended for High-Risk Individuals

The U.S. Preventive Services Task Force has published its final recommendations on lung cancer screening. The panel advises annual computed tomography (CT) scans for high-risk individuals (heavy smokers or former heavy smokers who have quit within the past 15 years) between 55 and 80 years of age. The recommendation is based on the results of a comprehensive review of the existing evidence and on modeling studies predicting the benefits and harms of different screening programs. Some experts have criticized the use of modeling data in developing the guidelines. Others consider practical concerns in implementing the recommendation, such as how to actually select those patients eligible and refer them to screening.


Taking Steps to Reduce Rates of Silica-Related Lung Cancer

Silica is a chemical found in sand and quartz and used in a multitude of industrial applications. Inhalation of silica dust can occur in a number of occupations and increases the risk of lung cancer. A recent review highlights new developments in understanding the health effects of silica exposure and recommends steps to reduce silica-related illness and death. Studies documenting the health risks associated with different levels of silica exposure have enabled evidence-driven regulations. Federal regulators are considering lowering the permissible occupational exposure to silica for workers, a measure that could cut the number of silica-related deaths in half. The review authors also recommend that workers exposed to silica who also smoke undergo computed tomography (CT) scans to screen for lung cancer starting at age 50 years.


Inflammation Markers Offer Clue About Lung Cancer Risk

Increased inflammation may be a warning of elevated lung cancer risk. A recent study analyzed blood samples taken from over 1,000 patients getting screened for lung cancer. Half of the patients went on to develop lung cancer in the following years. Eleven chemical markers of inflammation in the patients’ blood were associated with an increased risk of developing lung cancer. The researchers developed an inflammation score based on the levels of four of these inflammation markers. Patients with the highest inflammation score were 2.8 times more likely to develop lung cancer than those with the lowest score (3.4 times more likely if the patients were current smokers). This inflammation score may therefore serve to identify high-risk patients in the future.


CT Scans May Overdiagnose Lung Cancer

Low-dose computed tomography (LDCT) scans have emerged as an effective screening tool for lung cancer, especially in high-risk patients. However, the method may have a significant rate of overdiagnosis, that is, detection of cancers that would not have caused any symptoms during the patient’s lifetime. These cancers may be slow growing or otherwise clinically insignificant. Overdiagnosis can lead to unnecessary treatment, generating significant cost and anxiety and risking medical complications. A large study comparing LDCT screening with another screening method, chest radiography, estimated that 18.5% of the lung cancer cases detected represented overdiagnoses. For cases of non-small cell lung cancer (NSCLC) and bronchioalveolar carcinoma (cancer of the air sacs), estimated overdiagnosis rates were 22.5% and 78.9%, respectively.