Study shows PET/CT imaging can help diagnose and define occult recurrent cancer

Combined positron emission tomography and computerized tomography (PET/CT) can help diagnose occult (hidden) recurrent cancer, possibly a cancer patient’s greatest post-treatment fear, report a team of Israeli physicians in the December issue of the Society of Nuclear Medicine’s “Journal of Nuclear Medicine.”

PET and CT scans are standard imaging tools that allow clinicians to pinpoint the location of cancer within the body before making treatment recommendations. PET/CT involves sequential PET and CT imaging on the same device, allowing for simultaneous acquisition of functional (PET) and anatomical (CT) data. “PET/CT was found to indicate the presence of new malignancy and also precisely localize and define the extent of disease” in patients in whom recurring cancer was suspected, explained lead author and SNM member Ora Israel, M.D.

The physicians asked the question, “Is FDG-PET/CT Useful for Imaging and Management of Patients With Suspected Occult Recurrence of Cancer?” Their study points to an affirmative answer, said Israel, who also noted the need for these initial results to be confirmed in large studies with more homogenous patient populations. The research team studied 36 cancer patients for whom blood tests showed increasing levels of serum cancer markers during follow-up.

“PET/CT was the only test that showed whether recurrent tumors were indeed present,” and since anatomic information was obtained, the type of treatment that should be applied could be determined, she said. “This is clinically important, since no treatment could be planned in these patients without the benefit of this combined test,” added Israel, who is with the department of nuclear medicine at Rambam Medical Center and the B. Rappaport School of Medicine, Technion, Israel Institute of Technology, both in Haifa, Israel.

“If these results are confirmed by larger studies in patients with different types of malignant tumors, PET/CT may potentially be used in the future as the first imaging modality in this group of patients,” Israel said. “In some of these patients, further invasive diagnostic procedures may not be needed, and the treating physicians may proceed directly with the appropriate treatment strategy,” she added.

Israel noted that PET/CT is already playing a major role in a large variety of clinical indications in cancer patients. “The clinical dilemma of a suspicion of cancer raised by abnormal blood tests may be solved, and management of this patient group may be optimized by this imaging modality,” said Israel. The study produced “important and very promising results,” said Israel, “since they showed not only improved diagnostic accuracy of PET/CT over PET, as was initially hypothesized, but also the impact of patient management.”