CHICAGO - Conducting an FDG-PET scan on patients with head and neck or lung cancer can help reduce unnecessary or futile surgical interventions, according to research presented this week at the 2008 American Society of Clinical Oncology (ASCO) meeting.
"Detection of metastatic disease in head and neck cancer patients is critical to preoperative planning because surgical management is reserved for patients with locoregional disease," said Dr. Shannon Fogh, a resident in radiation oncology at Jefferson Medical College of Thomas Jefferson University in Philadelphia.
In her retrospective review of newly diagnosed head and neck cancer patients, she said that 156 PET scans of 157 patients who were negative later proved to be negative, for a 0.5% false-negative rate or a 99.5% negative predictive value. PET's sensitivity was 91% and specificity was 93%. Six percent of the patients were found to have metastatic disease.
However, the positive predictive value of PET was 45%, with 10 of 22 patients who underwent biopsy for suspicious lesions proving to have cancer. The suboptimal positive predictive value requires that "positive" PET findings be confirmed by "confirmatory imaging or ideally biopsy," Fogh said.
In a similar study, Dr. Donna Maziak, a thoracic surgeon at Ottawa Hospital in Ontario, said that she found that whole-body PET plus MRI or CT of the brain was more accurate than conventional staging -- CT of the liver and adrenals, total-body bone scan, and a CT or MRI brain scan -- for non-small cell lung cancer.
The conventional screening understaged 30% of 157 patients, while PET screening resulted in 11% of 163 patients being understaged.
"Preoperative staging with PET identifies more patients with mediastinal and extrathoracic disease compared to conventional staging," Maziak said at a press briefing. "Staging with PET spared more patients from stage-inappropriate surgery."
As Fogh noted, "Identifying distance metastases in an accurate and timely fashion can eliminate false hopes of surgical cure, result in timely and appropriate treatment of metastases or synchronous primary tumors, and eliminate the morbidity and mortality associated with extensive head and neck procedures."
By Edward Susman
AuntMinnie.com contributing writer
June 3, 2008
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