A histological grading system for gastric MALT lymphoma after treatment looks to be a promising tool for assessing residual disease in prospective drug trials. A pilot study has confirmed that the system has good internal reproducibility.

Good agreement was achieved among the scores of seven histopathologists who separately scored 45 sets of stained gastric biopsies for three criteria—lymphoid infiltrate, lymphoepithelial lesions, and stromal changes—from 10 patients treated for gastric MALT lymphoma. The results translated into four clinically meaningful scores: complete histological remission, probable minimal residual disease, responding residual disease, and no change.

The 10 patients comprised seven men and three women enrolled in one arm of a multicentre clinical trial of gastric MALT lymphoma and selected randomly. They had been treated to eradicate Helicobacter pylori and were followed up for a mean of 19 months, during which three to six sequential gastric biopsies were obtained. The histopathologists were blinded to the clinical results at follow up.

Gastric MALT lymphoma is closely associated with H pylori gastric infection. Eradicating the infection usually clears up the cancer, but ensuring patients are clinically clear of the disease entails prolonged follow up. Histological evaluation of residual disease is difficult but remains the only indication for the time being. The present standardised system was devised to help judge the extent of residual disease. Further testing of this scoring system on more patients is the next step, but in time it may be a useful complement to molecular studies.