Whole body PET/CT finds some tricky cancers better than CT alone
Danish researchers have found whole body PET/CT augmented by the radiotracer FDG is superior to straight CT as a first-line modality for imaging patients with serious non-specific symptoms and signs of cancer (NSSC). Their study was published online Jan. 12 in the Journal of Nuclear Medicine.
In introducing their work, Anne-Mette Lebech, MD, PhD, and colleagues at the University of Copenhagen note that a fast-track pathway has been established in Denmark to investigate patients with NSSC. These patients are not eligible to enter an organ-specific cancer program, they point out, and the prevalence of cancer in this cohort is approximately 20 percent.
“The optimal screening strategy in patients with NSSC remains unknown,” they write.
For the modality-comparison study, the team prospectively randomized 197 such patients 1:1 to whole body 18F-FDG-PET/CT or CT of the thorax and abdomen.
Study physicians established a tentative diagnosis after first-line imaging, then adjudicated the final referral diagnosis when sufficient data became available.
Thirty-nine (20 percent) of the patients ended up having diagnoses of cancer. Ten of them (5 percent) had an infection, 15 (8 percent) had an autoimmune disease and 76 (39 percent) had other diseases. In 57 patients (28 percent), no specific disease was found.
Comparing the modalities, the researchers found that 18F-FDG-PET/CT had yielded a higher specificity (96 vs. 85 percent; P = 0.028) and a higher accuracy (94 vs. 82 percent; P = 0.017) than CT alone.
They found no statistically significant differences in sensitivity (83 vs. 70 percent) or negative predictive values (96 vs. 92 percent), and there was no difference in days to final referral diagnosis.
However, for the subgroups where the imaging modality showed suspicion of malignancy, there was a significant delay to final diagnosis in the CT group compared to the 18F-FDG-PET/CT group (11.6 vs. 5.7 days; P = 0.02), the authors report.
“We found a higher diagnostic specificity and accuracy of 18F-FDG-PET/CT compared to CT for detecting cancer in patients with non-specific symptoms and signs of cancer,” they conclude. “18F-FDG-PET/CT should therefore be considered as first-line imaging in this group of patients.”
Dave P. has worked in journalism, marketing and public relations for more than 30 years, frequently concentrating on hospitals, healthcare technology and Catholic communications. He has also specialized in fundraising communications, ghostwriting for CEOs of local, national and global charities, nonprofits and foundations.