Concordance in interim PET reporting in the prospective HD 0607 clinical trial in advanced-stage Hodgkin lymphoma

Objectives Assess the role of chemotherapy intensification in ABVD-treated Hodgkin Lymphoma (HL) patients with PET2 positive after 2 cycles.

Methods After baseline PET patients were treated with 2 ABVD courses and performed PET2. All 169 non-physiological PET2 scan according to the local center (scan with any FDG uptake outside the physiological areas) were uploaded to WIDEN and reviewed by the expert panel. The PET2 were evaluated according to the Deauville criteria. PET2 pos patients shifted to BEACOPP or Rituximab-BEACOPP escalated treatment while PET2 neg ones continued with ABVD.

Results According to the results of the 367 reviewed patients, 64 (17.4%) were scored as positive and 303 (82.6%) were scored as negative. The 64 PET2 positive showed a single residual focus in 44 cases and multiple foci of residual uptake in 20 (10 of them with score 5). 38 showed lesions in the mediastinum, 24 in superficial lymph nodes and 2 in the lung. In 23 (64%) patients the single residual FDG uptake was within a bulky lesion and in 15 (36%) was outside. The concordance between couples of reviewers (Cohen’s Kappa) ranged between 0.77 and 0.87. The overall concordance among all the six reviewers (Krippendorf’s Alpha) was 0.80. In a cohort of 181 patients who completed the therapy with a mean follow-up of 522 days, 28 showed a positive and 153 a negative PET-2. Overall, 172/181 (95%) were in continuous complete response and 9 (5%) progressed or relapsed: 6 in the PET-2 positive and 3 in the PET-2 negative cohort.

Conclusions (1) the online review process for PET2 is feasible and simple (2) a very high binary and overall concordance rate among reviewers is obtained using the Deauville score for PET2 reporting; (3) most of the positive PET2 scan showed a residual FDG uptake in the site of bulky disease, mostly in mediastinum.

Research Support AIL Italian Lymphoma Societ