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PET-SCAN FOR RESPONSE ASSESSEMENT AFTER RITUXIMAB-DOSE-ADJUSTED-EPOCH (R-DA-EPOCH) IN PRIMARY MEDIASTINAL LARGE B-CELL LYMPHOMA (PMLBCL): CLINICAL AND PROGNOSTIC SIGNIFICANCE

PS1089

Vassilakopoulos, T.1; Chatzidimitriou, C.1; Mellios, Z.2; Verigou, E.3; Papageorgiou, S.4; Giatra, H.2; Kalpadakis, C.5; Gainaru, G.1; Karatsanis, S.6; Xanthopoulos, V.7; Koumarianou, A.8; Katodritou, E.9; Tsirogianni, M.10; Arapaki, M.1; Giannikos, T.1; Efstathopoulou, M.1; Karanakis, G.7; Simeonidis, A.3; Grentzelias, D.7; Sakellariou, K.2; Papadaki, E.5; Plata, E.1; Bakiri, M.2; Datseris, I.11; Chatziioannou, S.12; Prassopoulos, V.13; Konstantopoulos, K.1; Angelopoulou, M.1; Themistoklis, K.2; Rontogianni, P.11

doi: 10.1097/01.HS9.0000562648.03390.a7
Poster Session II: Aggressive non-Hodgkin lymphoma - Clinical
Free

1Department of Hematology, National and Kapodistrian University of Athens, Laikon General Hospital

2Department of Hematology, Evangelismos General Hospital, Athens

3Department of Hematology, University of Patras, Patra

42nd Propedeutic Department of Internal Medicine, National and Kapodistrian University of Athens, Attikon Hospital, Athens

5Department of Hematology, University of Crete, Heraclion

63rd Department of Internal Medicine, National and Kapodistrian University of Athens, Sotiria Hospital

7Department of Hematology, Hygeia Hospital

8Department of Hematology, Iaso General Hospital, Athens

9Department of Hematology, Theagenion Anticancer Hospital, Thessaloniki

10Department of Hematology, Ag Savvas Anticancer Hospital

11Department of Nuclear Medicine, Evangelismos General Hospital

12Department of Nuclear Medicine, Foundation for Biomedical Research of the Academy of Athens

13Department of Nuclear Medicine, Hygeia Hospital, Athens, Greece

Background: PET-scan has been evaluated in PMLBCL regarding its prognostic significance under R-CHOP and R-MACOP-B chemotherapy. Patients with clearly positive scans, and especially those with SUVmax ≥5 and Deauville 5-point scale (D5PS) score 5, have inferior outcomes even after consolidative radiotherapy (RT) [1,2]. However, after more intensive chemotherapy, as R-da-EPOCH, the prognostic significance of PET/CT can be modulated, since most patients with positive scans achieve durable remissions without consolidative RT, pointing out to the possibility of false-positive results [3].

Aims: To assess the clinical and prognostic significance of end-of-treatment PET (EOT-PET) in patients with PMLBCL and to evaluate the outcome of patients without subsequent RT

Methods: Among 54 patients with PMLBCL treated with R-da-EPOCH in 11 Greek Centers, 45 were evaluated with EOT-PET-scan after 6 cycles. PET evaluation was pending in 5 patients, whereas no data were available in 4 patients at the time of the analysis.

Results: The median follow-up from treatment initiation was 17 months. Among 45 evaluable patients, 6 had an EOT-PET D5PS of 1 (13%), 9 had D5PS 2 (20%), 13 had D5PS 3 (29%), 12 had D5PS 4 (27%) and 5 had D5PS 5 (11%). Among the 12 patients with D5PS 4, when evaluated according to the “1,4” criterion: 8 were reviewed as D5PS score 4 (SUVmax of residual lesion >1.4xSUVmaxliver) and 4 were reclassified as D5PS score 3 (SUVmax of residual lesion <1.4xSUVmaxliver). Thus the frequency of D5PS score 4 was reduced from 27% to 14% (6/43) with that of D5PS score 3 increasing from 29% to 40% (17/43). Only one of the patients with D5PS scores 1-3 (28 or 62% of total) actually received RT (a patient with D5PS score 2). Among the 12 patients with D5PS score 4, 5 were irradiated (42%). The SUVmax for these 5 patients was 2.9, 3.8, 4.3, 4.5, and 6.0 (4/5 were D5PS score 4 according to the “1.4” criterion). Two of them achieved complete metabolic remission (D5PS 1 and 2), the 3rd continued to have D5PS score 4 after RT and 2 had no available follow-up scans post-RT. Overall, none of the 40 patients with D5PS score 1-4 developed disease progression despite the omission of consolidative RT in 34/40 (85%). In contrast, all 5 patients with D5PS score 5 either progressed or received salvage chemotherapy. Data on follow-up scans will be presented at the Meeting.

Summary/Conclusion: PET/CT is a valuable tool for response assessment in PMBCL after R-da-EPOCH, greatly facilitating clinical decision making regarding further consolidative RT. In a real-life setting, RT was safely omitted in the vast majority of patients with EOT-PET D5PS scores 1-4 without even a single case of treatment failure. Patients with D5PS score 5 are rare and their handling requires further study.

Copyright © 2019 The Authors. Published by Wolters Kluwer Health Inc., on behalf of the European Hematology Association.