Open AccessPS1089 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
Author(s) -
Vassilakopoulos T.,
Chatzidimitriou C.,
Mellios Z.,
Verigou E.,
Papageorgiou S.,
Giatra H.,
Kalpadakis C.,
Gainaru G.,
Karatsanis S.,
Xanthopoulos V.,
Koumarianou A.,
Katodritou E.,
Tsirogianni M.,
Arapaki M.,
Giannikos T.,
Efstathopoulou M.,
Karanakis G.,
Simeonidis A.,
Grentzelias D.,
Sakellariou K.,
Papadaki E.,
Plata E.,
Bakiri M.,
Datseris I.,
Chatziioannou S.,
Prassopoulos V.,
Konstantopoulos K.,
Angelopoulou M.,
Themistoklis K.,
Rontogianni P.
Publication year - 2019
Publication title -
hemasphere
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 11
ISSN - 2572-9241
DOI - 10.1097/01.hs9.0000562648.03390.a7
Subject(s) - medicine , cohort , rituximab , incidence (geometry) , lymphoma , epoch (astronomy) , cyclophosphamide , gastroenterology , chemotherapy , stars , physics , astronomy , optics
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 >1.4xSUVmax liver ) and 4 were reclassified as D5PS score 3 (SUVmax of residual lesion <1.4xSUVmax liver ). 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 3 rd 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.