Hodgkin lymphoma (HL) with bulky mass - Staging and interim assessment using dual point FDG-PET/CT (2P-PET)

Objectives FDG PET/CT has an established role for early therapy response in patients (pts) with HL. However interpretation of interim PET/CT scans in patients with bulky lesions remain unsatisfactory. This might be the result of unspecific inflammatory reactions within the bulky lesions. We hypothesized that 2P-PET would help to differentiate reactive changes from active disease.

Methods To test this hypothesis we identified from March 2010 to December, 2011, 12 pts, age 39± 7,4 12 out of 84 pts with HL treated with ABVD at our institution in whom we performed 2P-PET at diagnosis and/or after 2nd ABVD cycle. FDGPET/CT studies were made using the BiographmCT and 6 scanners, 60 and 120 min after 5-7/MBq kg injection. Interim FDG-PET scans were graded according to the 5 point scale(5PS).We also assessed kinetics of FDG uptake between 60-120 min. The median follow up is 13 (2-21) months.

Results In the initial staging SUV values ranged between 8,7 and 21,5 (mean 12,3) and raised mean 3,5 between 60 and 120 min. Interim 2P-PETs were negative in 8 and positive in 4 pts according to 5PS. In 3 positive pts increase of SUV values, mean 2,9, after 120min was noted. Those pts subsequently relapsed. In 1 patient decrease of SUV uptake was noted and he remains in complete response. In the subgroup of negative pts, 1 patient after 60min had a slight increase in SUV value. Interestingly, this patient relapsed.

Conclusions Our preliminary results may suggest that the dynamic of the FDG uptake between 60 and 120 min in early PET assessment might be a useful factor predicting response to chemotherapy