Treatment, patterns of failure, and survival of patients with Stage I nodal and extranodal non-Hodgkin's lymphomas, according to data in the population-based registry of the comprehensive cancer centre west

Abstract

BACKGROUND: Primary extranodal lymphomas (EN-NHLs) are a heterogeneous category of tumors that are considered to be different from primary nodal non-Hodgkin's lymphomas (N-NHLs). To what extent these differences have clinical implications is currently not very clear, because knowledge of EN-NHL as a separate group is limited. METHODS: Using data from the Comprehensive Cancer Centre West (CCCW) population-based NHL registry in the Netherlands, N-NHL and EN-NHL patients were compared to determine differences in characteristics at diagnosis, responses to treatment, patterns of failure, and survival. RESULTS: At presentation, EN-NHL patients had poorer performance scores and more often bulky tumors compared with N-NHL patients, resulting in poorer responses to treatment (complete response rates were 72% and 84%, respectively; P=0.04) and inferior 5-year overall survival (49% and 63%, respectively; P=0.003). Among EN-NHL patients, considerable variations in response, survival, and relapse rates were observed, with gastric NHL patients having the best and central nervous system NHL patients having the worst prognosis (66% and 7% 5-year overall survival, respectively). Relapse rates for N-NHL and EN-NHL patients did not differ (39% and 36% 5-year relapse rates, respectively), whereas among EN-NHL patients considerable differences in relapse rates were noted. Relapses among N-NHL patients were mainly found in nodal sites, whereas recurrent disease in EN-NHL patients was mainly found in extranodal sites. CONCLUSIONS: In this population-based study, Stage I EN-NHL patients as a group had a poorer prognosis than N-NHL patients. However, among EN-NHL patients, considerable differences in response, relapse risk, and survival were observed. The failure analysis conducted in this study suggests that patterns of dissemination for N-NHL and EN-NHL are different.