POSTER'15'
THE'PREDICTIVE'VALUE'OF'INTERIM'FDGIPET/CT'FINDINGS'IN'GASTRIC'
DIFFUSE'LARGE'BICELL'LYMPHOMA'
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Maria! Eduarda! Couto1,! Isabel! Oliveira1,! Nelson! Domingues1,! Luisa! Viterbo1,! Angelo! Martins1,! Ilídia!
Moreira1,!Sérgio!Chacim1,!Ana!EspiritoJSanto1,!Dulcineia!Pereira1,!Cláudia!Moreira1,!Hugo!Duarte2!and!
José!Mariz1!
!
(1)OncoUhematology!Service,!Instituto!Português!de!Oncologia!do!Porto,!F.G.,!E.P.E.,!Porto,!Portugal,!
(2)Nuclear!Medicine!Service,!Instituto!Português!de!Oncologia!do!Porto,!F.G.,!E.P.E.,!Porto,!Portugal!
!
The! prognostic! value! of! the! intermediate! positron! emission! tomography! (PET)! scan! along!
first! line! therapy! in! gastric! diffuse! large! BJcell! nonJHodgkin! lymphoma! (gDLBCL)! is! not!
completely!clarified.!According!to!NCCN!it!can!lead!to!increased!false!positives!and!should!be!
carefully! considered! in! selected! cases! (if! positive,! reJbiopsy! is! suggested).! Some! studies!
found! that! the! positive! and! negative! predictive! values! of! InterimJPET! (relapse! or! disease!
progression)!are!57.1%!and!75.8%,!being!the!intermediate!PET!scan!more!likely!a!negative!
exam.!!
This! retrospective! study! analyses! the! value! of! intermediate! PET! scan! in! all! patients!
diagnosed!with!gDLBCL!between!january/2010!and!december/2018!in!one!institution.!
101!patients!were!analysed,!median!age!64!years!23J94,!50.5%!male.!Lugano!stage!was!I!in!
16.8%,!II1!in!20.8%,!II2!in!10.9%,!IIE!in!13.9%,!IV!in!34.7%.!RJCHOPJlike!treatment!was!used!
as! first! line! in! 94.8%! and! radiotherapy! in! 49.5%! (for! localized! disease);! 76.5%! obtained!
complete!response.!The!overall!survival!and!progression!free!survival!were!not!reached.!The!
median!followJup!(FU)!time!was!74!months.!Intermediate!PET!scan!along!first!line!treatment!
was!made!in!12!patients!(11,9%),!showing!complete!response!in!9!cases,!a!partial!response!
in! 2! and! progressive! disease! in! 1.! All! patients! with! complete! response! in! the! intermediate!
PET! scan! remained! cured! until! the! end! of! this! study.! Those! with! partial! response! in! the!
intermediated! PET! scan! (evidencing! sensitivity! to! the! treatment! in! course)! achieved! a!
complete!response!at!the!end!of!first!line!treatment!(which!was!completed!in!all!cases)!and!
sustained! their! responses! until! the! end! of! this! study.! The! only! patient! with! progressive!
disease! in! the! intermediate! PET! scan! was! not! able! to! eliminate! the! disease! (even! after! a!
second!line!treatment)!and!is!currently!in!supportive!care.!The!positive!predictive!value!of!
the! intermediate! PET! in! this! group! of! patients! was! 100%! (the! unique! patient! with!
progressive! disease! remained! resistant! to! the! treatment! in! course;! all! other! patients!
evidenced! chemotherapy! sensitivity! which! was! confirmed! later! in! the! end! of! first! line!
treatment).!
This! study! showed! that! a! short! number! of! patients! were! exposed! to! an! intermediate! PET!
scan! in! the! cohort,! evidencing! the! absence! of! agreement! about! its! relevance.! The!
intermediate!PET!scan!was!a!trustable!exam!to!predict!first!line!treatment!response!in!these!
12!patients,!however,!it!is!still!not!systematically!used!as!a!tool!to!decide!treatment!options!
given!the!lack!of!clinical!evidence.!
! !