In a nutshell
This study explored the accuracy and predictive power of FDG-PET/CT scans for measuring remaining disease after treatment in childhood non-Hodgkin lymphoma (NHL). This study determined that a negative scan was predictive of remission, but there was a high false positive rate.
Some background
FDG-PET scans measure regional glucose (sugar) uptake in the body. Cancer cells use glucose faster than normal cells. This activity will appear on an FDG-PET scan. The use of FDG-PET, combined with CT scans, has been shown to be an accurate predictor of treatment response and outcome in patients with Hodgkin lymphoma. It is also used to guide therapy, such as intensifying treatment if any remaining disease is found. However, it is not clear whether FDG-PET/CT is as predictive in NHL, or whether it is as specific as a biopsy (an invasive procedure where tissue is removed to test for cancer cells). The use of the scans in children for response assessment is unclear.
Methods & findings
The records of 18 childhood NHL patients were examined. All children underwent FDG-PET/CT scans after starting treatment, and all had biopsies within 2 weeks of the scan.
FDG-PET/CT scans identified 8 patients with suspected residual disease (a positive PET response). Other imaging methods (CT scans, ultrasound, or MRI) identified 15 patients with possible remaining disease. Biopsy confirmed residual disease in 2 patients.
Both of the positive biopsy patients has positive FDG-PET/CT scans. Two of the remaining FDG-PET/CT positive patients had early relapses. The other 4 were disease-free after an average of 4.7 years.
All patients with negative scans also had negative biopsies. The predictive power of a negative FDG-PET/CT scan was 100%. The predictive power of a positive FDG-PET/CT scan was 25%.
The bottom line
This study concluded that a negative FDG-PET/CT scan was a good predictor of outcome. However, the rate of false positives was high. The authors suggested that biopsy and close monitoring is required.
Published By :
British Journal of Haematology
Date :
Mar 01, 2015
