Using interim positron emission tomography as a predictor for relapse-free survival in hodgkin lymphoma: Experience from a single Institution

Background: Since the emergence of 18F-fluoro-2-deoxyglucose positron emission tomography (PET), PET has been widely implemented for the initial staging and evaluation of treatment response of classical Hodgkin lymphoma (cHL). Interim PET after two cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) has been proven to be a reliable tool to predict clinical outcomes in patients with cHL, and response-adapted therapies based on interim PET results have become the standard method of treatment. The aim of this study was to report our experience of using interim PET in our institution and determine whether it is a predictive marker for cHL. In addition, we also analyze associations between other patient characteristics and interim PET results at initial diagnosis. Materials and Methods: This retrospective study enrolled patients verified to have newly diagnosed cHL and who received ABVD as frontline treatment between 2008 and 2019 in our hospital. Interim PET was arranged after 2-3 cycles of ABVD, and we used Deauville 5-point score to evaluate the response. Subgroup analysis was performed to assess correlations between interim PET and patient characteristics. Results: Sixty patients underwent interim PET examinations. The age ranged from 14 to 74 years with a medium follow-up of 18.3 months (range: 4–113 months). The patients who had negative interim PET results (n = 36, 60%) had significantly longer relapse-free survival than those with positive results (P < 0.001). Patients with bulky disease, B-symptoms, or neutrophil to lymphocyte ratio (NLR) >6 were more likely to have positive interim PET-computed tomography results (P < 0.001, 0.023, and 0.037, respectively). Conclusion: Interim PET plays an important role in predicting relapse free survival for patients with Hodgkin lymphoma at our institution. A high NLR was correlated with interim PET results in this study.