Lymph node involvement rate in low-grade gastric mucosa-associated lymphoid tissue lymphoma--too high to be neglected

Anti-Helicobacter pylori (H. pylori) treatment for low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma has been the subject of attention. The aim of this study was to determine the proportion of such cases which could be suitable candidates for H. pylori eradication for the purpose of cure; we focused on gross morphology and lymph node metastasis.

We retrospectively reviewed the medical records of 53 patients diagnosed and treated for gastric MALT lymphoma at Seoul National University Hospital between 1992 and 1996.

According to Isaacson's classification, 60% of cases were low-grade, and H. pylori was detected in 88% of them. In low-grade disease, gastroscopy revealed superficial lesions in 56% of cases, ulcerofungating lesions were found in as much as 19%, and ulceroinfiltrating in 25%. Even in low-grade disease, invasion of proper muscle, or deeper, was seen in 28% of patients, and lymph node involvement in 36%; even in low-grade disease confined to mucosa and submucosa, the rate of lymph node involvement was 40%. All cases which, on gastroscopy, appeared to be gastritis or benign ulcer-like lesions were free of lymph node metastasis, but in low-grade disease, this proportion was only 16%. In 33% of cases, pre-operative clinical stage I--as shown by abdominal CT--was found post-operatively to be stage II. The negative predictive value of lymph node detection by CT was 68%.

In low-grade gastric MALT lymphoma, the lymph node involvement rate was too high to be neglected. In detecting lymph node metastasis, the diagnostic accuracy of CT was too low. The proportion of suitable candidates for anti-H. pylori treatment for low-grade gastric MALT lymphoma was not high, and in clinical practice, anti-H. pylori treatment in such cases should at present be very carefully applied.