Interim FDG-PET/CT for therapy monitoring and prognostication in Hodgkin's Lymphoma

The aim of the study was to assess the predictive value of interim FDG-PET/CT (iPET) in patients with Hodgkin's lymphoma (HL) treated with Adriamycin, bleomycin, vinblastine and dacarbazine (ABVD) chemotherapy. A total of 245 consecutive patients with de novo HL between 12/2013 and 12/2017 were evaluated retrospectively. All patients were treated with upfront ABVD, performed PET/CT scans at baseline, after 2 cycles (interim PET, iPET2) or 4 cycles (iPET4) and at the end of therapy, and followed up for at least 6 months after therapy. The response status on iPET was defined according to the standard five-point Deauville scores (DS) as follows: complete metabolic response (CMR, DS 1-3) and non-complete metabolic response (nCMR) (DS 4 and 5). End-of-treatment (EoT) response was assessed by FDG-PET/CT and if needed biopsy confirmation of PET-positive findings. The association between iPET and EoT response was investigated using logistic regression analysis. Survival analysis was performed using the Cox regression hazard model and Kaplan-Meier methods. Sixty-nine patients underwent iPET-2 and 176 iPET-4. No association was found between the timing of iPET and iPET response status (P-value = 0.71). Two hundred and one patients (82%) had iPET-CMR and 44 (18%) iPET -nCMR. iPET was strongly associated with EoT response status: 194/201 (96 .5%) of iPET-CMR had a complete response at the EoT while only 21/44 (47.7%) of patients with iPET-nCMR presented a complete response at EoT (P-value < 0.0001). The median follow-up was 32 months (range 6-81). Patients with iPET-CMR presented a better outcome with 91% 3 y event-free-survival (EFS) and 95% 3 y overall survival (OS) than those with iPET-nCMR (41 and 86%, respectively, P-value < 0.0001). In multivariable analyses, iPET retained an independent prognostic factor of EFS and OS (P-value < 0.0001 and P-value = 0.002, respectively). iPET is highly predictive of outcome of HL patients treated with ABVD and allows to tailor therapy to the individual patient.

Automated summary

The study assessed the predictive value of interim FDG-PET/CT in HL patients treated with ABVD chemotherapy. The results showed that iPET was strongly associated with treatment response and prognosis, and could help tailor therapy to individual patients.