PET scanning promising in diagnosing cancer-related neurological disorders


SAN FRANCISCO Positron emission tomography (PET) imaging has recently been shown to aid in the diagnosis of particular neurological syndromes associated with cancer. Study details and results will be presented at the American Academy of Neurology 56th Annual Meeting in San Francisco, Calif., April 24 May 1, 2004.

Before their cancer is even diagnosed, patients can develop problems with the brain, spinal cord or nerves, though the cancer has not spread to the nervous system. Called "paraneoplastic neurological disorders," these neurological problems occur as the body's immune system begins to fight the cancer cells, but accidentally attacks the brain or nerves as well. These problems are uncommon, difficult to diagnose, and usually appear in patients whose primary cancer is extremely difficult to find. Abnormal antibodies in the blood or spinal fluid are often associated with these disorders, though they cannot help identify the primary tumor.

PET imaging has been shown to improve detection of a variety of cancers, and earlier tests have suggested this technique may be useful in identifying small tumors in patients with paraneoplastic neurological disorders. But PET imaging is not yet widely available, and clear indicators of clinically meaningful outcomes using PET are essential to warrant use with this patient population.

"Accurately defining the role of this technique for these patients is critical," comments study author Steven Allder, MD, of the department of Neurology, Royal Hallamshire Hospital in Sheffield, United Kingdom. Toward this end, Adler and colleagues studied the use of PET imaging in 32 patients with suspected paraneoplastic neurological disorders who had not yet been diagnosed with cancer.

With each patient, all relevant investigations had been performed prior to PET imaging resulting in no diagnostic conclusions. Each patient then underwent PET imaging from neck to pelvis. All patients were then prospectively followed-up, with the results of all further investigation collected. Final diagnosis was determined, and the sensitivity and specificity of the results of the initial PET scan were calculated.

"This particular PET scanning in our patient population successfully yielded a high proportion of relevant lesions that were undetectable by alternative diagnostic means," reports Allder. Results of this study indicate that PET is an appropriate, promising tool for patients with undiagnosed paraneoplastic neurological disorders.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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