FDG-PET Interpreted By Deauville Criteria Prior to Allogeneic Transplantation Predicts Outcomes in Patients with Relapsed or Refractory Hodgkin Lymphoma

Background: Despite high curative rates with upfront therapy, 20-30% of patients (pts) with Hodgkin lymphoma (HL) experience disease relapse. Survival is further diminished for those who fail autologous stem cell transplantation (ASCT). However a fraction of pts can still be salvaged with allogeneic hematopoietic cell transplantation (allo-HCT).

Methods: In this retrospective cohort study, we investigated the prognostic significance of FDG-PET (interpreted by both standard and Deauville criteria) among 42 consecutive patients with relapsed/refractory (RR) HL undergoing allo-HCT from 2004-2012. All FDG-PET scans were obtained within 4 weeks prior to allo-HCT. The study cohort included recipients of non-myeloablative (NMA) conditioning consisting of fludarabine 150-200 mg/m², cyclophosphamide 50 mg/kg and total body irradiation TBI 200 cGy followed by transplantation of umbilical cord blood (n=30; 71%), matched related (n=10; 24%) and unrelated (n=2; 5%) donor grafts.

Results: The median age was 28 years (range, 6-59); 52% were males. Median time from HL diagnosis to allo-HCT was 34.6 months (range, 13.3-228.6) and median follow up of pts was 26.5 months (range, 0.8-97.1). Pts had received a median of 4 lines (range, 3-9) of prior regimens with 83% failing ASCT; only 13 pts (31%) had achieved PET-negative (neg) CR prior to allografting. Blinded re-evaluation of all pre-HCT FDG-PET scans using Deauville 5-point scale (i.e. PET_D-pos if Deauville>3) by independent nuclear medicine physicians, confirmed all pre-existing PET-neg reports, but also reclassified 4 prior PET-pos scans as PET_D-neg (kappa coefficient=0.79 [95% CI, 0.61-0.98] for PET_D vs. archived PET). All 17 PET_D-neg pts had significantly better 3-yr post-transplant OS, PFS, and relapse rate as compared to PET_D-pos pts (100% vs. 51%; 76% vs. 17%; 24% vs. 65%, respectively; all p<0.01, Figure). Three out of four reclassified PET_D-neg pts remained alive and in remission after a median follow up of 3.3 years (range, 1.0-8.0). Three-year non-relapse mortality for all pts was 7% (0% for PET_D-neg vs. 12% for PET_D-pos, p=0.1). Pre-HCT PET_D-neg status remained prognostic for improved 3-yr OS (HR=0.1; 95% CI, 0-0.86) and lower relapse risk (HR=0.34; 95% CI, 0.1-1.0) in the multivariable Cox models.

Conclusions: Our study demonstrates encouraging outcomes achieved with NMA allo-HCT in heavily pre-treated pts (3-yr OS, PFS and relapse of 72% [95% CI, 54%-84%], 40% [95% CI, 24%-55%], 48% [95% CI, 29%-66%], respectively). FDG-PET imaging interpreted by Deauville criteria can serve as a powerful prognostic tool in pts with RR HL considered for NMA allo-HCT.