High prognostic value of one negative F18 FDG PET/CT for cure of malignant lymphomas

Background: The 18-fluorodeoxyglucose positron emission tomography or computed tomography (F18 FDG PET/CT) is a highly sensitive method for determining sites of disease in the diagnosis of lymphoma. F18 FDG PET/CT in post-treatment lymphoma is capable of distinguishing fibrosis from residual active lymphoma. No studies hitherto have addressed the value of a negative PET/CT scan during follow-up. Objective: To determine the incidence and consequence of a negative scan and record the active recurrence or lesion metastasis after negative F18 FDG PET/CT finding in lymphoma patients. Materials and Methods: The present study was done retrospectively, including 82 consecutive Hodgkin's and non-Hodgkin's lymphoma patients with a negative F18 FDG PET/CT finding between January 2008 and December 2013. Demographic and clinical data were collected and analyzed. Results: Seventy-two of 82 negative F18 FDG PET/CT studies (87.8%) had no evidence of disease recurrence, with a mean follow-up of 1,401 days (range 120 to 3,037). Ten of 82 negative F18 FDG PET/CT studies (12.2%) developed recurrent disease, with a mean time of recurrence after PET/CT of 642 days (range 50 to 1,205). Conclusion: Normal F18 FDG PET/CT scan after lymphoma treatment was found to be associated with low incidence of disease recurrence for a long time. Only 10 (12.2%) patients in the present study had disease recurrence, with a mean recurrence time at after PET/CT of 642 days.