Would repeat MMR/HER-2 or NGS testing be beneficial during progression of gastric cancer in patients who have already received first line chemotherapy?

There are really no good data one way or another, as far as I know, so any views expressed here are purely anecdotal and personal opinions.

As a group and speaking for myself, I rarely repeat NGS. The bigger picture is that we identify actionable alterations in esophagogastric cancer no more than 5% ...