Waldeyer's ring lymphomas: A clinical study from the comprehensive cancer center west population based NHL registry

It is debated whether non-Hodgkin's lymphomas originating in Waldeyer's rin g (WR NHL) behave as NHL originating in lymph nodes or share common feature s with extranodal lymphomas originating in mucosa associated lymphatic tiss ue (MALT). We analyzed data from a population based NHL registry on pattern s of dissemination at diagnosis, response to treatment, patterns of failure and survival of 77 primary Waldeyer's ring Non-Hodgkin's lymphomas (WR NRL ) patients. Data of completely staged patients with diffuse large cell lymp homas (DLCL) originating in WR (n=44) were compared with those of patients retrieved from the same registry with DLCL originating in lymph nodes or st omach (the latter as prototype of a lymphoma originating in MALT). Primary WR NHL had favorable risk scores according to the International Prognostic Index (IPI), and responded well to therapy: a complete response (CR) rate o f 74% was observed. Disease free survival (DFS) and overall survival (OS) w ere poor, however (47% and 31% at 10 years, respectively). The comparison of DLCL originating in WR, lymph nodes and stomach revealed that WR and gastric NHL patients shared a restricted pattern of disseminati on at diagnosis, in contrast to patients with DLCL originating in lymph nod es. Although not all patients were completely restaged at relapse, analysis of patterns of failure suggested that the gastro-intestinal tract is a pre ferential site for recurrences, both for WR and gastric DLCL patients. CR r ates of WR, nodal and gastric DLCL patients were 77%, 55% and 55% respectiv ely (P=0.03), OS of the three patient subgroups did not differ (33%, 27% an d 37% at 10 years). DFS of WR DLCL patients was similar to nodal DLCL patie nts but inferior to gastric DLCL patients (47%, 48% and 73% at 10 years res pectively, P=0.006). After Cox regression analysis the relative relapse ris k for patients with WR DLCL when compared to patients with DLCL originating in lymph nodes was 2.01 (C.I. 0.99-4.01, P=0.05), and 3.46 (C.I. 1.32-9.00 , P=0.01) when compared to patients with gastric DLCL. The clinical picture of primary WR NHL emerging from this population based study is in agreement with data form hospital based studies. In the compari son of WR DLCL, nodal DLCL and gastric DLCL, the observed patterns of disse mination suggest similarities between WR DLCL and gastric DLCL. The frequen t relapses after CR observed for WR DLCL patients, however, indicate that t hese lymphomas clinically behave as nodal DLCL, and should be treated accor dingly.