Predictive value of interim PET/CT visual interpretation in the prognosis of patients with aggressive non-Hodgkin's lymphoma

Objective: The objective of the study was to evaluate the prognostic value of positron emission tomography (PET)/computed tomography (CT) visual interpretation in patients with aggressive non-Hodgkin's lymphoma (NHL) using a meta-analysis and systematic review.

Methods: Using the PubMed, Embase, and Web of Science databases, we performed a systematic review of the use of visual evaluation mid-chemotherapy to evaluate the prognosis of aggressive NHL in studies published up to May 2017. Prospective and retrospective studies assessing progression-free survival (PFS) and overall survival (OS) were included. We used hazard ratio (HR) to determine the value of Deauville criteria and International Harmonization Project (IHP) criteria for measuring survival. Subgroup analysis was performed based on the number of chemotherapy cycles before the mid-term evaluation as well as the visual evaluation method.

Results: A total of 11 studies were included. PFS (HR =2.93, 95% confidence interval [CI]: 2.93-3.90, p<0.0001) and OS (HR =2.55, 95% CI: 1.76-3.68, p<0.0001) of PET/CT-positive patients were significantly lower when determined by the visual method. In subgroup analysis, IHP, Deauville criteria, and having no standard interpretation groups were factors able to predict PFS; IHP and having no standard interpretation group were able to predict OS. With PET/CT, IHP, and Deauville 5-point criteria, the PFS of patients receiving 2-4 cycles of chemotherapy before PET/CT was significantly lower than that of PET/CT-negative patients. No significant difference in OS was observed when patients received 3 or fewer cycles of chemotherapy before PET/CT, though OS was significantly lower in patients receiving more than 3 chemotherapy cycles.

Conclusion: IHP and Deauville criteria are commonly used for PET/CT visual evaluation at present. Interim PET/CT analysis after 3-4 chemotherapy cycles is capable of predicting disease prognosis. Large-scale prospective clinical trials are needed to confirm whether PET/CT analysis can be used as an indication for changing a treatment strategy.