Primary gastric lymphoma and its grades of malignancy.

Summary From 1904 through December 31, 1965, 126 patients with primary gastric lymphoma were operated on at the Mayo Clinic. The patients had blood studies which gave normal results and preoperatively gave no indication of the tissue diagnosis. Of 108 patients treated by partial gastric resection (group A), about 65 per cent survived more than five years. Of seven patients treated by total gastrectomy (group B), three survived more than five years. The lesions of the remaining eleven patients (group C) were so far advanced that primary curative surgery could not be performed. These were treated by roentgen ray therapy alone. One patient survived more than five years after such “palliative” treatment. The 108 patients in group A (treated by subtotal gastrectomy) were subdivided as follows: in group A1 were eighty-one patients with “typical” (deeply invasive) primary gastric lymphoma who survived the immediate postoperative phase; in group A2, five patients with comparable lesions who died postoperatively; in group A3, sixteen patients who exhibited superficial gastric lymphomas with microscopic pictures like those of group A1 but with no invasion of the muscularis propria; in group A4, six patients who had primary Hodgkin's disease of the stomach. (Nodal involvement was present in four cases of group A3.) Group A1 was subdivided further into four groups according to grade of malignancy. Five- year survivals for grades I through 4 were 94, 81, 66, and 36 per cent, respectively. The overall five year survival rate for subgroup A1 was 67.9 per cent, for group A3 75 per cent, and for group A4 66 per cent. The five year survival rate for group B was 42.8 per cent, including the two patients who died postoperatively, and 60 per cent excluding them. The five year survival rate for group C was 9 per cent. The histologic grade of malignancy of gastric lymphomas was determined by the cellular details and the quantitative estimation of the most frequent cell types. Every lymphoma is a mixture and one will therefore find all cells of the lymphocytic line in every lesion; however, the quantitative composition varies with the grade of malignancy. For the microscopic evaluation of gastric lymphomas, we found that one needs to compile an “average” grade based on examination of at least six representative slides for each lesion because of variation within the lesion. The size of the lesion was of some prognostic importance, smaller lesions carrying a more favorable outlook than larger ones. Superficially growing lymphomas which did not involve the muscularis propria were not associated with a significantly better rate of cure than were the infiltrating lymphomas of comparable size. Peritoneal involvement was a prognostic sign of minor significance, but lymph nodal involvement by itself indicated a grave outlook. Only 40 to 50 per cent of our patients in groups A and B survived five years if they had involvement of lymph nodes. If it is necessary to perform total gastrectomy to remove a gastric lymphoma, because of either extent or position, the performance of the operation appears to be justifiable. Furthermore, roentgen ray therapy by itself definitely can effect cure and one should never fail to employ this form of treatment if it is impossible to perform curative surgery.