Should adjuvant CRT be considered in gastric cancer patients who received pre-op chemo based on the recent results of the CRITICS trial?

There are many nuances here, but CRITICS suggests that there is little if any benefit to the routine use of postoperative chemoRT, in addition to pre- and post-op chemo, in resected gastric cancer patients who undergo a D2 dissection. The only scenario where I really consider postop CRT to be strongly indicated in the postop setting is for a positive margin.

Is there still a potential role for adjuvant CRT? Of course, but the potential scenarios are increasingly narrowing in light of CRITICS and other recent results. For example, though lymph node involvement has been suggested as an indication for postop CRT due to the ARTIST trial results, suggesting a PFS benefit in the node-positive subset; the ARTIST II trial results, reported at ASCO last year, failed to demonstrate a benefit to CRT in these patients. One can still speculate about, and apply individualized clinical judgment to, particular scenarios, such as patients who undergo <D2 dissection, or have minimal pathologic response to preop chemotherapy, or have a very high burden of nodal involvement.

I would also point out, as the CRITICS authors do in their manuscript, that the trial isn't necessarily an ideal comparison of postop RT vs. no postop RT, because patients were randomized before starting therapy, and many patients never received postop therapy as randomized. I think that adjuvant RT still may have an important role to play in gastric cancer, but if so it will probably be better seen and applied in the preop setting rather than postop, which would be more analogous to what we are doing in esophageal cancer, and which is currently being tested in the TOPGEAR trial.