Comparison of 18F-labelled fluoro-2-deoxyglucose-PET with conventional computed tomography for staging and response assessment in paediatric and adult patients with nodular lymphocyte-predominant Hodgkin's lymphoma.

BACKGROUND: Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is an uncommon subtype of Hodgkin lymphoma. Data are limited regarding 18F-labelled fluoro-2-deoxyglucose (FDG)-PET use in NLPHL. We are reporting our experience with FDG-PET utility in staging and response assessment NLPHL patients. METHODS: We retrospectively studied a population of all newly diagnosed or relapsed/refractory patients who underwent both pre-treatment contrast-enhanced computed tomography (CeCT) and an FDG-PET and also at the end of planned treatment. RESULTS: We identified 68 patients found to have in total 312 scans, 78 paired pre-therapeutic and post-treatment CeCT and FDG-PET scans. Among them, 55 were male, with a median follow-up was 48 months. Median SUV-max was 8.3 (2.0-21.0). FDG-PET and CeCT were concordant in 80% (62/78) of staging scans. In 20% (16/78) of patients in whom a discordance was observed, FDG-PET resulted in upstaging in 13 scans and downstaging in 3 scans. The sensitivity of CeCT was 92% for nodal staging and 42% for extralymphatic staging when compared to FDG-PET. The specificity of CeCT was 98% as compared to FDG-PET. For response assessment, there was poor agreement between the CeCT and FDG-PET in assigning complete remission of disease scores as FDG-PET was able to identify the absence of disease despite the presence of a radiologically evident residual mass on CeCT. The sensitivity for CeCT compared to FDG-PET was 100% while the specificity was 43% for detection of post-treatment response. CONCLUSION: For NLPHL, pre-therapeutic FDG-PET scan is better than CeCT staging. FDG-PET has much better specificity for response assessment than CeCT.

High-dose chemotherapy and autologous stem cell transplantation for relapsed or refractory nodular lymphocyte predominant Hodgkin lymphoma.

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a distinct subtype of Hodgkin lymphoma. We report our results of relapsed/refractory NLPHL patients who received high-dose chemotherapy and autogenic stem cell transplantation (HDC auto-SCT). Seventeen NLPHL patients received HDC auto-SCT (1996­2014): male 14 and female 3, with median age at diagnosis of 22 years, at HDC auto-SCT 28 years (15­58 years). At the time of relapse/progression, 13 (76 %) had NLPHL and 4 (24 %) had transformed diffuse large B cell lymphoma. The reason for HDC auto-SCT was refractory NLPHL in 12 patients and relapsed in 5 patients. Salvage chemotherapy was etoposide, methylprednisolone, cisplatinum, and Ara-C (ESHAP); eight patients also received rituximab with ESHAP. HDC was carmustine, etoposide, cytarabine, and melphalan (BEAM). Post-auto-SCT, complete remission was achieved in 14 (82 %), partial remission in 1 (6 %), and progressive disease in 2 (12 %) patients. The median follow-up is 63 months from auto-SCT (6­124 months). Of the nine patients who received only ESHAP, four had post-auto-SCT events versus no event in all eight patients who received rituximab+ESHAP. Kaplan­Meier estimates of 5-year event-free survival for the whole group is 76 %: rituximab+salvage (100 %) versus salvage alone (56 %), P=0.041. Overall survival is 94 %: 100 versus 89 %, respectively, P=not significant (NS). Even in refractory NLPHL patients, long-term disease-free survival is possible after HDC auto-SCT. Post-auto-SCT relapse or progression can still be managed with chemo/chemo+immunotherapy/ radiation. These encouraging results of rituximab in salvage setting should be explored further in a clinical trial setting for this patient population.