Favorable radiation field decrease in gastric marginal zone lymphoma : Experience of the German Study Group on Gastrointestinal Lymphoma (DSGL).

Abstract

Long-term impact of stage-adapted field reduction in alarge cohort of gastric marginal zone lymphoma (gMZL) patients treated conservatively with curative radiation therapy (RT). Prospective analysis of paper records of 290 patients with stage IE-IIE gMZL, treated in 78radiotherapeutic institutions in Germany from 1992-2013. Stage-adapted radiation fields decreased from extended field (EF) to involved field (IF) over the course of three consecutive prospective trials of the German Study Group on Gastrointestinal Lymphoma (DSGL). Treatment results were compared between the three cohorts. Overall collective with median age of 60years, slight male predominance (m:f = 1.1:1) and ratio of disease stageI:stage II = 2.1:1. Median follow-up 6.4years in total: 13.0 years in the first gastrointestinal study (GIT 1992), 8.2years in the second (GIT 1996) and 4.7years in the third study (DSGL 01/2003). Stage-adapted radiation field decrease together with further technological development led to reduced relative frequencies of acute/chronic adverse effects and until now was accompanied by lower disease recurrence. The third study design with smallest field size (IF in stageI, locoregional EF in stageII) achieved the best survival outcome at the 5‑year follow-up (overall survival 92.7%, event-free survival 89.5% and lymphoma-specific survival 100.0%). Disease relapse observed in 10patients. Cumulative incidence of disease-specific death was 1.7% of the followed patients. Primary disease stage associated with lymphoma-specific survival. Stage-adapted reduction towards IF in gMZL resulted in favorable adverse effects, local control and survival rates. These results support further decreases in modern RT of gMZL.