Clinical characteristics, treatment, and outcome of primary rectal lymphoma: a single center experience of 16 patients

BACKGROUND: The rectum is a relatively uncommon site for lymphoma compared with other gastrointestinal sites; no consensus regarding management of primary rectal lymphoma (PRL) has been formed due to its limited frequency. We aimed to investigate clinical characteristics and treatment outcomes in patients with PRL in a single center patient cohort. METHODS: We retrospectively analyzed the results of 16 consecutive patients with PRL, identified and treated at the Asan Medical Center, Seoul, Korea between January 1993 and December 2014. RESULTS: These 16 patients with PRL constituted 0.8% of all non-Hodgkin's lymphoma patients (N=1,984). B-cell lymphomas (N=14) made up the majority of the series, and half of these were extranodal marginal zone lymphomas (ENMZL, N=7). Ten patients received systemic chemotherapy with (N=3) or without rituximab (N=7), and 4 of these received additional local therapy. The others received radiotherapy (N=3) or endoscopic mucosal resection (N=3). Twelve patients (75%) achieved complete response (CR) after first-line treatment. Event-free survival (EFS) and overall survival (OS) in stages IE and IIE were significantly longer compared with stages IVE (P=0.001 and P=0.001, respectively). All patients with ENMZL (N=7) achieved CR during or after initial treatment. CONCLUSION: PRL is very rare and seems to present mostly as B-cell type. Stage is the most important prognostic factor, with significantly better survival associated with localized diseases. ENMZL may be one of the most common types of PRL with favorable treatment outcomes.