Whole-body PET/CT screens Li-Fraumeni patients for range of cancers

April 22, 2008

Though whole-body PET/CT is expensive, it may prove its worth by periodically screening Li-Fraumeni syndrome patients for the emergence of various cancers that are characteristic of the rare and dangerous genetic disorder.

Though whole-body PET/CT is expensive, it may prove its worth by periodically screening Li-Fraumeni syndrome patients for the emergence of various cancers that are characteristic of the rare and dangerous genetic disorder.

LFS patients are extremely susceptible to a range of cancers that can appear anywhere in the body, frequently when the patient is young. Preliminary research from the Dana-Farber Cancer Institute in Boston showed that whole-body fluorine-18 FDG-PET/CT scanning identified unsuspected but treatable tumors in three of 15 patients studied.

"These patients can develop brain tumors as well as sarcomas and various types of tumors that can occur anywhere in the body," said Dr. Annick Van Den Abbeele, clinical director of radiology and director of nuclear medicine/PET at Dana-Farber. "So having a modality that can look at the entire body at once is quite advantageous."

Published in the March 19 issue of the Journal of the American Medical Association, these initial findings indicate that whole-body screenings using dual modalities may detect more tumors at a curable stage compared with other diagnostic options.

"As of now, we have little to offer patients with this frightening syndrome. The only screening modalities available to them are regular physical examinations, mammograms, breast MRI, and colonoscopies. PET/CT is more likely to supplement these techniques than to replace them," said lead author Dr. Serena Masciari.

Using PET/CT, doctors found papillary thyroid cancer in a 31-year-old breast cancer survivor and in a 48-year-old survivor of breast cancer and childhood sarcoma. The body scan also revealed esophogeal adenocarcinoma in a 36-year-old male LFS patient with no history of cancer.

Ultimately, Van Den Abbeele believes PET/CT may prove to be the most affordable method for screening LFS patients.

"Here we have a modality that not only provides you with anatomic and functional information, it allows you to look at the patient from head to toe for a price that's less than what you would have to do using comprehensive whole-body CT or MRI," she said. "You have to put the price in perspective of what these patients would undergo should the PET/CT not be available."

In addition, the body scan offers advantages in terms of time. It takes about half an hour compared with two hours minimum that it would take for a patient to be have an MRI of the brain, head, neck, chest, abdomen, and pelvis.

Masciari said that they will still need to be cautious about the radiation when it comes to developing a regular screening schedule for these cancer-prone individuals, but PET/CT scanning allows for flexibility in minimizing the dose to the patient compared with standard diagnostic CT scanning.

"We also need to know if there is a high rate of false-positive findings from screening that would have to be followed up," she said.

Masciari and Van Den Abbeele emphasize the results are preliminary. They have yet to establish if every LFS patient would benefit from whole-body PET/CT exams. Follow-up research involving more patients will aim at determining when and at what time increments screenings should be performed. Ways to minimize radiation exposure will also be considered, Van Den Abbeele said.

For more information from the Diagnostic Imaging archives:

Experts outline pros and cons of functional MR and PET in clinical area

Whole-body imaging need more tailored approach to be effective

Oncology tasks require disease-specific PET/CT