Mesothelioma Screening - Imaging Scans
In patients with potentially resectable disease, MR imaging can provide additional staging information. Use of different pulse sequences and gadolinium-based contrast material can help differentiate between tumor and normal tissue. Relative to adjacent chest wall muscle, MPM is typically iso- or slightly hyperintense on T1-weighted images and moderately hyperintense on T2-weighted images. MPM enhances with use of gadolinium-based contrast material. The excellent contrast resolution of MR imaging can allow improved detection of tumor extension, especially to the chest wall and diaphragm, and better prediction of overall resectability. Anatomic and morphologic MR imaging features similar to those seen at CT are used to establish local invasion of MPM. Loss of normal fat planes, extension into mediastinal fat, and tumoral encasement of more than 50% of the circumference of a
medi-astinal structure are some of the MR imaging features that suggest tumor extension.
A recent study showed that MR imaging is superior to CT in revealing two types of invasive growth of MPM: invasion of the diaphragm and invasion of endothoracic fascia or a single chest wall focus . MR imaging is most useful in evaluating patients with questionable areas of local tumor extension at CT or in whom intravenous administration of iodinated contrast material is contraindicated.
Chest x-ray: This may show irregular thickening of the pleura, calcium deposits on the pleura, or fluid in the pleural space. These findings suggest asbestos exposure leading to the development of a mesothelioma.
Imaging studies such as x-rays, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans will help determine the location, size, and extent of the cancer.
Computed tomography (CT): The CT scan is an X-ray procedure that produces detailed cross-sectional images of your body. Instead of taking one picture, like a conventional x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these pictures into an image of a slice of your body. The machine will take pictures of multiple slices of the part of your body that is being studied.
CT scans are often used to make the initial diagnosis of malignant mesothelioma, and are helpful in staging the cancer (determining the extent of its spread).
Often after the first set of pictures is taken you will receive an intravenous injection of a "dye" or radiocontrast agent that helps better outline structures in your body. A second set of pictures is then taken. CT scans are more tiring than regular x-rays because they take longer and you need to lie still on a table while they are being done. But just like other computerized devices, they are getting faster and your stay might be pleasantly short. Also, you might feel a bit confined by the ring you lie within when the pictures are being taken. You will have an IV (intravenous) line through which the contrast "dye" is injected. The injection can also cause some flushing (redness and warm feeling).
Some people are allergic and get hives or rarely more serious reactions like trouble breathing and low blood pressure. Be sure to tell the doctor if you have ever had a reaction to any contrast material used for x-rays. You may be asked to drink 1 to 2 pints of a solution of contrast material. This helps outline the intestine so that it is not mistaken for tumors.
Detecting Mesothelioma Using CAT / CT Scan
CT / CAT (computed axial tomography) scans are basically three dimensional x-rays that are able to project extremely detailed internal pictures of the organs, bones and skeletal structures. CT scan is a method of combining images from multiple x-rays using a computer to reproduce cross sectional or three-dimensional pictures of internal organs. It is useful in determining the location and spread of mesothelioma. They are much more accurate in detail than the x-ray, helping the physician / surgeon make a more accurate diagnosis. One of the drawbacks of CT scans is that it cannot differentiate between benign or malignant mesothelioma.
Positron Emission Tomography (PET Scan): In this test, radioactive glucose (sugar) is injected into your vein. Because cancers use sugar much faster than normal tissues, the cancerous tissue takes up the radioactive material. A scanner can spot the radioactive deposits. This test, which is still being
studied, is useful for telling whether a thickening of the tissues is cancer or merely scar tissue. It can also spot spread of the cancer.
Detecting Mesothelioma Using PET Scans
PET imaging is the best and most widely used imaging technology for diagnosing mesothelioma. PET scans use cameras and tracers that form images to indicate biological changes which are able to detect extremely small cancerous tumors. They are much superior in their image quality and details when compared to x-rays, CAT scans, and even MRI scans. PET scans also help the physician / surgeon in determining the staging of the cancer.
Magnetic resonance imaging (MRI): MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of tissue and by certain diseases. A computer translates the pattern of radio waves given off by the tissues into a very detailed image of parts of the body. Not only does this produce cross sectional slices of the body like a CT scanner, it can also produce slices that are parallel with the length of your body. A contrast material might be injected just as with CT scans, but is used less often. Sometimes MRI scans are
useful in looking at the diaphragm (the thin muscle at the bottom of the lung cage that is responsible for breathing) where the mesothelioma may spread.
MRI scans are particularly helpful in examining the brain and spinal cord. MRI scans are a little more uncomfortable than CT scans. First, they take
longer - often up to 1 hour. Also, you have to be placed inside a tube, which is confining and can upset people with claustrophobia (fear of enclosed places). The machine also makes a thumping noise that you may find disturbing. Some places will provide headphones with music to block this out.
Detecting Mesothelioma Using MRI Scan
MRI scans are more sophisticated than the x-ray and CT scans. It makes use of high magnetic fields and radio waves, and with the help of a computer give physicians / surgeons a clear picture of the internal organs and skeletal structure. MRI scans are extremely clear and very useful in detecting mesothelioma related soft tissue growths and determining the severity of the tumor.
Mesothelioma and Early Lung Cancer Identified by Screening
Posted on Tuesday, May 26, 2009.
Using computed tomography scans to screen former asbestos workers can detect both early and late-stage lung cancer and late-stage mesothelioma, according to a study in the May Journal of Thoracic Oncology. However, it’s still not clear whether screening for these cancers might improve patients’ prognoses.
Exposure to asbestos fibers is a known risk factor for lung cancer and the cause of mesothelioma. Although asbestos is still not completely banned in theU.S., it was phased out of American industry to a large degree beginning in the 1970s. However because asbestos-related diseases can take 20 to 40 years to emerge after people have been exposed, former asbestos workers and those exposed to products containing this carcinogen continue to be diagnosed with asbestos caused cancers.
As researchers search for better treatments and even a cure for these diseases, they are also focusing on new diagnostic methods that might identify the cancers earlier. Early diagnosis is particularly crucial with mesothelioma, because many patients survive only one year after they first start to show signs, and symptoms are often difficult to distinguish from those of other lung diseases.
One potential screening method uses low-dose computed tomography (LDCT) to evaluate the lungs and their lining (pleura). LDCT can locate plaques in the lungs, which are a sign of asbestos exposure and have been linked to an increased cancer risk.
Currently, there are no recommendations about using LDCT or any other method to screen people who have been exposed to asbestos, and screening isn’t routinely done. “There are currently no methods for the early detection of mesothelioma available,” says lead author Heidi Roberts, MD, Associate Professor of Radiology at theUniversity ofToronto. “This is why we are doing the research.”
To determine the effectiveness of LDCT as a screening tool for asbestos-related lung cancers, Dr. Roberts and her colleagues recruited 516 people (most of them men) who had been exposed to asbestos at least 20 years before, or who had known plaques. Participants were given LDCT scans of the chest. Patients who had abnormal scans were given follow-up tests. Those with normal test results were invited to have an annual LDCT scan.
Of the 516 participants, 357 had evidence of plaques. Based on the results of the first scan and annual scans, six of the patients were diagnosed with lung cancers and four were diagnosed with mesothelioma.
Although LDCT was able to detect advanced mesothelioma, as well as early- and late-stage lung cancers, it was not able to diagnose early mesothelioma. The study authors say they need to continue screening patients to help them get a better idea of what early mesothelioma looks like. Also, they say adding biomarkers (substances in the blood that indicate the presence of cancer) to the screening process may provide greater sensitivity to help diagnose those at very high risk for mesothelioma.
Even as techniques are fine-tuned, screening is just one step of a three-tiered effort to combat these cancers, according to Dr. Roberts. “The second step is the parallel development of biomarkers, and the third step is the parallel development of treatment strategies,” she says. “These have to be developed hand-in-hand in order to make this a useful and meaningful tool.”
Roberts HC, Patsios DA, Paul NS, dePerrot M, Teel W, Bayanati H, Shepherd F, Johnston MR. Screening for malignant pleural mesothelioma and lung cancer in individuals with a history of asbestos exposure. Journal of Thoracic Oncology. 2009;5:620-628.
Prometheus announces new mesothelioma diaPrometheus Launches ProOnc Dx Cancer Diagnostics
Thu Oct 15, 2009 7:00am EDT
Three New Tests Based on Breakthrough MicroRNA Technology
SAN DIEGO, Oct. 15 /PRNewswire/ -- Prometheus Laboratories Inc., a specialty
pharmaceutical and diagnostic company, today announced the nationwide
commercial launch of three new cancer diagnostic products: ProOnc TumorSource
Dx, ProOnc Squamous Dx and ProOnc Mesothelioma Dx. Each of these tests is
based on recently developed, highly sensitive microRNA technology.
"Prometheus has a long and successful history of providing innovative
diagnostics that complement targeted therapeutics to help physicians
individualize patient care," said Joseph M. Limber, President and Chief
Executive Officer of Prometheus. "Now we are proud to introduce the first
three products from our cancer diagnostics portfolio with the launch of ProOnc
Dx. We believe that these highly tissue-specific tests provide more objective
and quantitative results than current methods, which, may lead to more
personalized treatments for patients."
ProOnc TumorSource Dx identifies the tissue-of-origin of a metastatic tumor.
The test identifies 25 different tumor types, including colon, liver, brain,
breast, kidney, lung, ovary, pancreas, prostate and testis, and measures the
expression level of 48 microRNA biomarkers. ProOnc TumorSource Dx uses a
proprietary classifier to assign a primary site to the cancer sample based on
the microRNA expression in the tumor and may become a critical tool in the
detection of cancer of unknown primary (CUP).
ProOnc Squamous Dx classifies non-small cell lung carcinoma tumors into two
histological groups: cancers of squamous histology and non-squamous cancers.
The test measures the expression level of a squamous microRNA biomarker to
differentiate patients that have squamous cell carcinoma of the lung from
patients that have non-squamous non-small cell lung cancer.
ProOnc Mesothelioma Dx is a cutting-edge molecular diagnostic test that uses
microRNA to differentiate malignant pleural mesothelioma from peripheral
adenocarcinoma of the lung and metastatic carcinomas involving the lung and
"MicroRNAs are small, non-coding sequences of RNA that are critically
important in many biological and pathological processes," saidHarveyPass,
M.D., Professor of Cardiothoracic Surgery and Director of the Division of
Thoracic Surgery and Thoracic Oncology atNew YorkUniversity Langone Medical
Center and its NYU Cancer Institute. "The sensitivity and specificity of
microRNA-based diagnostics should enable clinicians to differentiate
particular cancer tissues with increased confidence, which may ultimately
guide medical oncologists to deliver the safest and most efficacious therapy
for their patients."
For more information about ProOnc Dx tests, please call (877) 378-4919 or
Prometheus acquired exclusiveU.S. rights to ProOnc TumorSource Dx, ProOnc
Squamous Dx and ProOnc Mesothelioma Dx from Rosetta Genomics (Nasdaq: ROSG) in
April 2009. The tests are offered as miRview mets, miRview squamous and
miRview meso outside of theU.S. In addition, Prometheus and Rosetta are
collaborating to develop two new microRNA-based gastroenterology tests.
Prometheus Laboratories Inc. is a specialty pharmaceutical and diagnostic
company committed to developing and commercializing novel pharmaceutical and
diagnostic products to help physicians individualize patient care. Prometheus
is a leader in applying the principles of personalized medicine to the
diagnosis and treatment of gastrointestinal diseases and is applying these
principles to oncology. Its strategy includes the marketing and delivery of
pharmaceutical products complemented by proprietary diagnostic testing
services. By integrating pharmaceutical products and diagnostic testing
services, Prometheus believes it can address the full continuum of care,
thereby providing physicians with a comprehensive solution to treat chronic
diseases. Prometheus' corporate offices are located inSan Diego.
ProOnc TumorSource Dx, ProOnc Squamous Dx and ProOnc Mesothelioma Dx are
trademarks of Prometheus Laboratories Inc. miRview mets, miRview squamous and
miRview meso are trademarks of Rosetta Genomics Ltd.
OURCE Prometheus Laboratories Inc.
Pete DeSpain, Director, Investor Relations & Corporate Communications of
Prometheus Laboratories Inc., +1-858-587-4117, firstname.lastname@example.org; or
John F. Kouten, Chief Executive Officer of JFK Communications, Inc.,
+1-609-514-5117, email@example.com, for Prometheus Laboratories Inc.