Primary gastrointestinal non-Hodgkin's lymphoma: I. Anatomic and histologic distribution, clinical features, and survival data of 371 patients registered in the German Multicenter Study GIT NHL 01/92.

Purpose: The study was initiated to obtain epidemiologic data and information on anatomic and histologic distribution, clinical features, and treatment results in patients with primary gastrointestinal non-Hodgkin's lymphomas (PGI NHL).

Patients And Methods: Between October 1992 and November 1996, 371 PGI NHL patients were eligible to evaluate clinical features. Radiotherapy and chemotherapy were stratified according to histologic grading, stage, and whether surgery had been carried out or not.

Results: A total of 74.8% patients had gastric NHL (PGL). Within the intestine, the small bowel and the ileocecal region were involved in 8.6% and 7.0% of the cases, respectively. Multiple GI involvement (MGI) was 6.5%. Approximately 90% of the GI NHL were in stages IE/IIE. Aggressive NHL accounted for the majority, with a distinguishable pattern in several sites. Forty percent of PGL were of low-grade mucosa-associated lymphatic tissue type. One third of large-cell lymphomas had low-grade components. Most intestinal NHL were germinal-center lymphomas. The site of origin was prognostic. In gastric and ileocecal lymphoma, event-free (EFS) and overall survival (OS) were significantly higher as compared with the small intestine or MGI (median time of observation, 51 months). In PGL, localized disease was prognostic for EFS and OS. Histologic grade influenced only EFS significantly. Numbers in intestinal lymphomas were too small for subanalyses.

Conclusion: PGI NHL are heterogeneous diseases. The number of localized PGL allowed for detailed analyses. Larger studies are needed for stages III and IV and for intestinal NHL. A uniform reporting system for PGI NHL, in terms of definitions and histologic and staging classifications, is needed to facilitate comparison of treatment results.