Abstract
Purpose: The clinical role of 18F-fluorodeoxyglucose (FDG)-positron emission tomography-computed tomography (PET/CT) in performing upfront high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) remains unclear in peripheral T cell lymphomas (PTCLs). This study investigated the prognostic relevance of interim and final FDG-PET/CT in predicting the outcome of upfront ASCT for the treatment of PTCLs.
Method: The study conducted newly diagnosed 96 patients with PTCLs who aged under 65 years between January 2005 and December 2016 from two independent institutions. For making a comparison of clinical outcome between transplant and non-transplant patients according to interim or final FDG- PET/CT, 37 transplanted and 59 non-transplanted patients with the same populations were evaluated as a comparative group (non-ASCT). The enrolled patients were treated with mainly anthracycline-based chemotherapy except patients with NK/T cell lymphoma who were treated with non-anthracycline-based. If achieved complete or partial remission after primary treatment, patients proceeded to upfront ASCT. FDG-PET/CT was performed at the time of diagnosis, interim, and after primary treatment. The response of interim or final FDG-PET/CT was analyzed by visual assessment using Deauville five-point scale (5-PS).
Results: The characteristics of transplant patients were similar to non-transplant patients except two features (IPI score, CT response). Final FDG-PET/CT response (P<0.001, Hazard ratio (HR) 3.51), CT response (P<0.001, HR 2.11) and age (P=0.005, HR 1.07) were significant prognostic factors of progression-free survival (PFS) in transplant patients on multivariate analysis. In non-ASCT patients, final FDG-PET/CT response (P<0.001, HR 9.65), prognostic index for T-cell lymphomas (PITs) score (P=0.001, HR 5.24), and CT response (P<0.001, HR 2.34) were prognostic for PFS. After a median follow-up of 60.8 months, 5-year PFS rates of ASCT and non-ASCT patients according to interim FDG-PET/CT response were 75.5 vs 74.5% of Deauville score 1-2, 20% vs 22.2% of Deauville score 3 and 33.3% vs 42.2% of Deauville score 4, respectively (P=0.092, P=0.005; Figure 1A, 1C). 5-year PFS rates according to final FDG-PET/CT response of ASCT and non-ASCT patients were 70.2% vs 80.5% of Deauville score 1-2, 22.2% vs 25% of Deauville score 3 and 0% vs 0% of Deauville score 4, respectively (P<0.001, P<0.001; Figure 1B, 1D).
Conclusion: Final FDG-PET/CT response based on Deauville 5-PS had prognostic significance on the treatment outcome of PTCLs regardless of upfront ASCT. However, patients with ≥ 3 of Deauville score assessed by interim or final FDG-PET/CT had poor prognosis even though performing upfront ASCT.
No relevant conflicts of interest to declare.
