Aggressive primary gastrointestinal lymphomas: review of 91 patients treated with the LNH-84 regimen. A study of the Groupe d'Etude des Lymphomes Agressifs. PURPOSE: Patients with aggressive primary gastrointestinal lymphoma undergoing the LNH-84 chemotherapy regimen were analyzed to determine the efficacy of intensive combination chemotherapy, the role of surgical debulking in patients treated with combination chemotherapy, and the toxicity associated with each of these modalities. PATIENTS AND METHODS: Ninety-one patients with primary gastrointestinal lymphoma who participated in the prospective multicenter LNH-84 combination chemotherapy trial (total number of patients in trial, 737) were analyzed. These 91 patients included 69 (76%) with diffuse large cell, nine (10%) with diffuse mixed, and seven (8%) with small noncleaved cell lymphoma. Two patients (2%) had stage IE, 54 patients (59%) stage IIE, and 35 patients (38%) stage IV disease; all patients with stage IE, 22 with stage IIE, and 18 with stage IV disease had bulky (greater than or equal to 10 cm) tumors. Specific sites of gastrointestinal involvement included stomach (47%), small bowel (38%), ileocecum (14%), colon (11%), and rectum (7%). Although surgical resection was attempted in 71 patients (78%), only 28 (31%) had complete tumor excision. All patients received three or four cycles of ACVB (defined in text) induction therapy followed by sequential consolidation as previously described. RESULTS: Responses to treatment in the 91 patients included 71 (78%) complete remissions, six (7%) partial remissions, five (5%) nonresponses, and nine (10%) deaths. With a median follow-up of 3 years, 10 patients (14%) have had relapses; predicted 4-year disease-free survival of complete responders is 85% and predicted 4-year survival of the entire group is 62%. In patients with stage IE or IIE disease, the complete response, survival, and disease-free survival rates were similar in those who underwent complete surgical resection or incomplete or no surgical resection prior to the administration of combination chemotherapy. Prognostic factors predicting for survival in the 91 patients with primary gastrointestinal lymphoma were similar to those in the 646 other patients treated with the LNH-84 regimen. CONCLUSIONS: Patients with aggressive gastrointestinal lymphoma treated with intensive chemotherapy have outcomes and prognostic factors comparable to those of patients with similar-stage aggressive lymphoma without primary gastrointestinal involvement. Surgical resection prior to the administration of combination chemotherapy did not influence the complete response rate, survival rate, or disease-free survival rate in this small group of patients. 