title: Limited clinical benefit for surveillance PET-CT scanning in patients with histologically transformed lymphoma in complete metabolic remission following primary therapy.
abstract: The optimum follow-up of patients with transformed indolent lymphoma (TrIL) is not well defined. We sought to determine the utility of surveillance positron emission tomography-computed tomography (PET-CT) in patients with TrIL achieving complete metabolic remission (CMR) after primary therapy. We performed a retrospective analysis of patients with TrIL treated at Peter MacCallum Cancer Centre between 2002 and 2012 who achieved CMR after primary therapy who had ≥1 subsequent surveillance PET-CT. Of 55 patients with TrIL, 37 (67 %) received autologous stem cell transplantation as consolidation following chemoimmunotherapy. After a median follow-up of 34 (range 3-101) months, the actuarial 3-year progression-free (PFS) and overall survival (OS) were 77 % (95 %CI 62-86 %) and 88 % (75-94 %), respectively. Of 180 surveillance PET-CT scans, there were 153 true negatives, 4 false positives, 1 false negative, 7 indeterminate and 15 true positives. Considering indeterminate scans as false positives, the specificity of PET-CT for detecting relapse was 94 %, sensitivity was 83 %, positive predictive value was 63 % and negative predictive value was 98 %. All seven subclinical (PET detected) relapses were of low-grade histology; in contrast, all nine relapses with diffuse large B cell lymphoma (DLBCL) were symptomatic. In our cohort of patients with TrIL achieving CMR, PET-CT detected subclinical low-grade relapses but all DLBCL relapses were accompanied by clinical symptoms. Thus, surveillance imaging of patients with TrIL achieving CMR is of limited clinical benefit. PET-CT should be reserved for evaluation of clinically suspected relapse.
authors.affiliation: Department of Haematology, Peter MacCallum Cancer Centre, Locked Bag 1, A'Beckett St, East Melbourne, 8006, Victoria, Australia.
authors.forename: Chan Y
authors.initials: CY
authors.lastname: Cheah
authors.forename: Michael
authors.initials: M
authors.lastname: Dickinson
authors.forename: Michael S
authors.initials: MS
authors.lastname: Hofman
authors.forename: Anupkumar
authors.initials: A
authors.lastname: George
authors.forename: David S
authors.initials: DS
authors.lastname: Ritchie
authors.forename: H Miles
authors.initials: HM
authors.lastname: Prince
authors.forename: David
authors.initials: D
authors.lastname: Westerman
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Harrison
authors.forename: Kate
authors.initials: K
authors.lastname: Burbury
authors.forename: Max
authors.initials: M
authors.lastname: Wolf
authors.forename: Henry
authors.initials: H
authors.lastname: Januszewicz
authors.forename: Kirsten E
authors.initials: KE
authors.lastname: Herbert
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Carney
authors.forename: Constantine
authors.initials: C
authors.lastname: Tam
authors.forename: John F
authors.initials: JF
authors.lastname: Seymour
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008223:Lymphoma / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods; D012074:Remission Induction / Q000379:methods; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome