Most aggressive lymphomas are sensitive to first-line immunochemotherapy and are in first Complete Remission (CR) with initial therapy. CR significantly decreases the risk of recurrence and increases survival. However, a cure is not guaranteed and approximately one third of lymphoma patients have a relapse disease.
FDG PET/CT is a valuable noninvasive tool in the evaluation of lymphomas, especially to differentiate viable lymphoma and fibrosis or necrosis in residual mass.
The majority of relapses are diagnosed based on clinical symptoms reported by patients. And the role of FDG PET/CT for routine surveillance of patients after treatment is controversial.
However, many medical centers use routine follow-up FDG PET/CT in addition to physical examination and laboratory analysis to detect subclinical relapse.
Thus, we can imagine a good timing to routine FDG PET/CT when the tumor burden is small in the asymptomatic window.
Survival improvement for relapse detected by routine follow-up imaging is not clearly established compared to diagnosis by clinical symptoms.
Several studies tried to assess the value of follow-up FDG PET/CT but population, type, timing and duration of surveillance imaging was very heterogeneous.
