Posttreatment PET/CT Rather Than Interim PET/CT Using Deauville Criteria Predicts Outcome in Pediatric Hodgkin Lymphoma: A Prospective Study Comparing PET/CT with Conventional Imaging

Abstract

Data about the significance of F-FDG PET at interim assessment and end of treatment in pediatric Hodgkin lymphoma (HL) are limited. Patients (≤18 y) with HL were prospectively evaluated with contrast-enhanced CT (CECT) and PET combined with low-dose CT (PET/CT) at baseline, after 2 cycles of chemotherapy, and after completion of treatment. Revised International Working Group (RIW) criteria and Deauville 5 point-scale for response assessment by PET/CT were used. All patients received doxorubicin (Adriamycin), bleomycin, vinblastine, dacarbazine chemotherapy along with involved-field radiotherapy (25 Gy) for early stage (IA, IB, and IIA) and advanced stage (IIB-IV) with bulky disease. Of the 57 enrolled patients, median follow-up was 81.6 mo (range, 11-97.5 mo). Treatment decisions were based on CECT. At baseline, PET/CT versus CECT identified 67 more disease sites; 23 patients (40.3%) were upstaged and of them in 9 patients (39%) upstaging would have affected treatment decision; notably none of these patients relapsed. The specificity of interim PET/CT based on RIW criteria (61.5%) and Deauville criteria (91.4%) for predicting relapse was higher than CECT (40.3%) ( = 0.03 and < 0.0001, respectively). Event-free survival based on interim PET/CT (RIW) response was 93.3 ± 4.1 versus 89.6 ± 3.8 (positive vs. negative scan, respectively; = 0.44). The specificity of posttreatment PET/CT (Deauville) was 95.7% versus 76.4% by CECT ( = 0.006). Posttreatment PET/CT (Deauville) showed significantly inferior overall survival in patients with positive scan versus negative scan results (66.4 ± 22.5 vs. 94.5 ± 2.0, = 0.029). Interim PET/CT has better specificity, and use of Deauville criteria further improves it. Escalation of therapy based on interim PET in pediatric HL needs further conclusive evidence to justify its use. Posttreatment PET/CT (Deauville) predicts overall survival and has better specificity in comparison to conventional imaging.

FDG PET in response evaluation of bulky masses in paediatric Hodgkin’s lymphoma (HL) patients enrolled in the Italian AIEOP-LH2004 trial

“…Among patients who received radiotherapy, PET-negative patients also showed a longer TTP than PET-positive patients, although they received a higher dose of radiotherapy. These results are similar to those of the studies discussed above [11,12] in which both early and late therapy response assessment with 18 F-FDG PET were able to identify paediatric HL patients with longer survival. Comparing the calculated predictive values for all three PET scans (i.e.…”

“…This difference was also seen between patients with PR in the range 50-75% and those with a response of ≥75%. Furthermore, Bakhshi et al [12], in a recent study evaluating the role of interim FDG PET after two cycles of chemotherapy in a paediatric HL cohort, found that interim PET/CT had a significantly higher specificity than conventional imaging. However, they did not recommend treatment reduction based on the interim PET/CT assessment by either the Revised International Working Group criteria or the Deauville score, as few patients would have benefited from less intense therapy.…”

“…The excellent results produced so far have created the need for new paediatric studies with the aim of reducing treatment-related morbidity while maintaining high survival rates. Multicentre trials have been conducted or are currently ongoing, mainly focusing on this aim [10][11][12].…”

Prognostic value of baseline, interim and end-of-treatment 18F-FDG PET/CT parameters in extranodal natural killer/T-cell lymphoma: A meta-analysis

“…Previous studies have confirmed that the DS, where values of 1–3 are defined as negative results and 4–5 are defined as positive results on I-PET/CT, can better predict PFS and OS, with good concordance among reviewers and inter-reader reliability in HL and NHL [ 40 – 42 ]. Jiang et al [ 25 ] evaluated the prognostic value of I-PET/CT using the DS and found that NPVs were better than PPVs in predicting PFS and OS, with NPVs of 87.5% and 96.9%, respectively, and PPVs of 60.7% and 39.3%, respectively.…”

Interim FDG-PET/CT in Hodgkin lymphoma: what are we actually looking at?

“…In other studies on the value of interim FDG-PET/CT in patients with advanced-stage Hodgkin lymphoma treated with ABVD, the predictive value was less strong, with PFS rates ranging between 28.8% and 43% for those with positive interim FDG-PET/CT results [6][7][8]. Of note, in two recent studies including an ABVD treated cohort of early-and advanced-stage Hodgkin lymphoma patients, interim FDG-PET/CT had minor or no predictive value at all, with interim FDG-PET/CT positive patients having PFS of 56.3% [9] and 100% [10], respectively. In patients treated with BEACOPP, the prognostic value of interim FDG-PET/CT diminishes drastically.…”