Prognostic Significance of PET CT in Relapsed/Refractory Diffuse Large B Cell Non-Hodgkin Lymphoma Before Transplantation of Autologous Hematopoietic Progenitors: Experience of a Public Hospital

Context: Patients with RR DLBC NHL after first-line of treatment who undergo a salvage chemotherapy regimen and subsequent consolidation with autologous stem cell transplant have a progression-free survival (PFS) and overall survival (OS) of nearly 80% (1). The response to the second line of chemotherapy assessed by PET CT before ASCT becomes an independent prognostic factor to predict outcome (2). Objective: To analyze the results of PET CT before ASCT as a prognostic factor; to determine the PFS and OS of patients undergoing PET CT before ASCT; to compare the PFS and OS of our population to the results reported in the international literature. Design and setting: This is an observational retrospective cohort study based on the collection of information from the ASCT records of the Hospital “El Cruce” Nestor Kirchner. We included 20 patients with RR DLBC NHL who underwent PET CT prior to performing ASCT. Analysis of qualitative variables was carried out with measures of central tendency and dispersion and of quantitative variables with summary measures. Results: A large majority of patients (75%, n= 15) were in complete remission (CR) prior to ASCT. The other 25% (n=5) were in partial remission (PR). There were only 4 (20%) post-transplant relapses. In the group of patients who were in PR before ASCT, 20% (n=1) relapsed after the procedure, and this event was recorded in 20% (n=3) of those who achieved CR before ASCT. The 2-year PFS of the entire group was 83%, and the 5-year OS was 76%. The 2-year PFS for patients who had achieved CR was 80% while for patients in PR it was 80% (p=0.9). The 5-year OS of both was 76% (p=0.87). Conclusions: Even though we have not been able to establish statistically significant differences between the two groups, we have identified similar trends to those published in the international literature. Although our population of patients achieved good outcomes and there was an appropriate follow-up time, the group of patients with PR was very small, and this is probably an important bias to prove a worse outcome in that group. References: [1] Raut LS, Chakrabarti PP. Management of relapsed-refractory diffuse large B cell lymphoma. South Asian J Cancer. 2014;3(1):66-70. doi:10.4103/2278-330×.126531. [2] Charles Mesguich. Prognostic value of pre-transplant 18-FDG PET/CT in Diffuse Large B Cell Lymphoma after R-DHAC salvage therapy. J Nucl Med May 1, 2018 vol. 59 no. supplement 1 1425.