The predictive role of interim PET after the first chemotherapy cycle and sequential evaluation of response to ABVD in Hodgkin’s lymphoma patients—the Polish Lymphoma Research Group (PLRG) Observational Study

Abstract Background Interim PET after two ABVD cycles (iPET2) predicts treatment outcome in classical Hodgkin’s lymphoma. To test whether an earlier assessment of chemosensitivity would improve the prediction accuracy, we launched a prospective, multicenter observational study aimed at assessing the predictive value of iPET after one ABVD (iPET1) and the kinetics of response assessed by sequential PET scanning. Patients and methods Consecutive patients with newly diagnosed classical Hodgkin’s lymphoma underwent interim PET scan after one ABVD course (iPET1). PETs were interpreted according to the Deauville score (DS) as negative (−) (DS 1–3) and positive (+) (DS 4, 5). Patients with iPET1 DS 3–5 underwent iPET2. Results About 106 early (I–IIA) and 204 advanced (IIB–IV) patients were enrolled between January 2008 and October 2014. iPET1 was (−) in 87/106 (82%) or (+) in 19/106 (18%) of early, and (−) in 133/204 (65%) or (+) in 71/204 (35%) of advanced stage patients, respectively. Twenty-four patients were excluded from response analysis due to treatment escalation. After a median follow-up of 38.2 (3.2–90.2) months, 9/102 (9%) early and 43/184 (23%) advanced patients experienced a progression-free survival event. At 36 months, negative and positive predictive value for iPET1 were 94% and 41% (early) and 84% and 43% (advanced), respectively. The kinetics of PET response was assessed in 198 patients with both iPETs. All 116 patients with iPET1(−) remained iPET2(−) (fast responders), 41/82 with IPET1(+) became iPET2(−) (slow responders), and the remaining 41 stayed iPET2(+) (non-responders); progression-free survival at 36 months for fast, slow and non-responders was 0.88, 0.79 and 0.34, respectively. Conclusion The optimal tool to predict ABVD outcome in HL remains iPET2 because it distinguishes responders, whatever their time to response, from non-responders. However, iPET1 identified fast responders with the best outcome and might guide early treatment de-escalation in both early and advanced-stage HL.