Excellent Outcome of Nodular Lymphocyte Predominant Hodgkin Lymphoma in the Eastern Province of Saudi Arabia. a Real-World Case Series of 49 Consecutive Patients Treated at a Referral Center from 2006 to 2017

Background Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a rare subtype of HL for which optimal treatment is controversial. We retrospectively reviewed the files of patients with NLPHL diagnosed and followed up at our institution and describe clinical characteristics and outcome and explore prognostic factors for progression-free survival (PFS) and overall survival (OS). Methods We included consecutive patients diagnosed with NLPHL and followed at King Fahad Specialist Hospital, Damamm (KFSH-D), a referral center for the Eastern Province of Saudi Arabia. Primary aim of this study was to determine clinical outcomes (PFS and OS) according to treatment strategy, i.e. radiotherapy (+/- Rituximab) (RT) only, chemotherapy (+/- Rituximab) (CT), combined modality (+/- Rituximab) (CMT), Rituximab monotherapy (R), and active surveillance (AS). Secondary aim was an exploratory analysis of candidate prognostic factors for PFS and OS. PFS was defined as time (months) from date of diagnosis to disease progression or death from any cause. Event time distributions were estimated using the method of Kaplan-Meier and groups were compared using the log-rank test. We used univariable and multivariable PFS analyses for candidate prognostic factors. Results From 1/2006 to 12/2017 data on 49 patients treated at KFSH-D, aged 16 years (y) or older, with a diagnosis of NLPHL and with sufficient treatment and follow-up (F/U) were analyzed. Median age at diagnosis was 29y (range, 16-56), 76% were male. Histology was typical in 86% (n=42), variant in 8% (n=4), and with transformed histology at diagnosis in 6% (n=3) of cases. Disease characteristics: 63% (n=31) of patients were stage I/II and 37% (n=18) stage III/IV, B-symptoms 12%, extranodal disease 10%, splenic involvement 8%, bulky disease (≥5 cm) 12%, and bone marrow involvement 4% of patients. The German Hodgkin Study Group (GHSG) score was intermediate-risk and high-risk in 53% (n=26) and 24% (n=12) of patients, respectively. Management strategy (MS), depending on physician's preference, was RT (16%, n=8), CT (43%, n=21), CMT (27%, n=13), R (6%, n=3), and AS (8%, n=4). For patients induced with chemotherapy +/- RT, ABVD-like (+/- Rituximab) (n=25) or CHOP (+/- Rituximab) (n=9) were used in all cases. The overall response rate (ORR) for 45 patients who received treatment was 91% (complete responses (CR), 69%), 98% ORR when cases with transformed histology at diagnosis were excluded. Median F/U was 36 months (m), (ran