Researchers at Dana-Farber Cancer Institute report that full-body PET/CT scanning detected unsuspected, treatable tumors in 3 of 15 patients with Li-Fraumeni syndrome (LFS), a rare genetic cancer syndrome for which no screening tests have been recommended.

The results suggest that periodic scans in combination with physical exams might catch more tumors at a curable stage, the investigators report in the March 19 issue of the Journal of the American Medical Association. But they caution that further, larger studies are needed to determine whether PET/CT screening is beneficial in LFS patients, who are highly susceptible to a variety of cancers from an early age because of an inborn gene mutation.

"We need to be cautious, and we shouldn't say that every patient with the syndrome should have a PET/CT examination," said Annick Van Den Abbeele, MD, clinical director of radiology and director of nuclear medicine/positron emission tomography (PET) at Dana-Farber. "But the study showed some interesting findings that justify a larger, international study in these patients."
PET detects cancers by tracking their abnormal appetite for sugar (glucose) compared to normal tissues, while CT (computed tomography) uses X-rays to show anatomical and structural details. Combining the two modalities in a single machine allows a patient to undergo both exams in one session; the resulting images are superimposed to reveal the precise location of suspected tumors.

LFS is a rare hereditary cancer syndrome named for the researchers who first described it, Frederick Li, MD, of Dana-Farber and Joseph Fraumeni Jr., MD, of the National Cancer Institute. In most cases, the cause is a mutation in the TP53 tumor suppressor gene that can be inherited and creates a high risk of a variety of malignancies, including sarcomas, breast cancer, leukemia, brain tumors, and many more common cancers at unusually early ages, including childhood. Among individuals with LFS, the chance of developing any cancer has been estimated at 50 percent by age 30, and 90 percent by age 60. A survivor of one cancer has a high risk of developing a new malignancy over time.

The syndrome is usually diagnosed after several members of a family develop early-onset tumors, prompting a test for the mutated gene. At present, there is no specific screening test to detect cancers before they become symptomatic in people carrying the Li-Fraumeni mutation because they are prone to such a wide variety of cancer types.

"We decided to study this in the adult LFS population because PET/CT scanning is used in the care of many of the type cancers that occur in LFS. Both LFS families and physicians have been frustrated by the lack of information for families with a rare and burdensome condition," said Judy Garber, MD, MPH, senior author of the paper and director of Dana-Farber's Cancer Risk and Prevention Clinic.

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