Clinical Case Discussion Forum

If the patient has sustained MMR on a reduced dose, that is a satisfactory response and should not materially change the risks of bariatric surgery (assuming normal blood counts). If it is considered beneficial for her overall health, then there is no contra-indication from a CML perspective. The low-dose imatinib should be continued as much as possible through the perioperative period – given the reduced dose she should not miss more doses than necessary.

If the indications for bariatic surgery are strong, the patient should go ahead with the procedure. Imatinib should be discontinued a day or two before the procedure and resumed once the patient is stable and feeding well.

With due respect to others, I would like to take a much deeper look at this than the previous commenters, as the answer to this question is not simple. Without going into the imatinib response, let us look at the whole idea of bariatric surgery. So, in many ways it should be examined like food effects and PPI/ H2 usage. For a more intensive and extensive look, there is a rather complete recent narrative review out there - Ghasoub, Frontiers of Oncology 2025 - that I saw a few months ago and enjoyed reading. This is not a simple question.

Bariatric surgery crosses the boundaries of reduction in stomach size, reduction in mucosal surface area, pH, food effects, concomitant mediations particularly acid production blockers such as PPIs, and drug interactions. The above review deals with many of these in an easy to understand format with good tables. If we restrict ourselves to the bariatric surgery alone, there is one important question - what is meant by bariatric surgery here? In the first case, this is the sleeve method which is simply putting a band around the stomach reducing the size. This is less effective, but has fewer issues and usually none with the use of TKIs including imatinib.

The other method is the by-pass approach using the roux-en-y surgical method. This removes part of the stomach, reduces acid production, by-passes part of the duodenum and has major implications in terms of volume, surface area, pH etc, very similar to the effects of taking a TKI with food or in a patient on a PPI.

There is a literature on TKI use for CML with 4 drugs - IM, DAS, NIL, and BOS. If there is anything with other widely used drugs, I have missed it. Drug efficacy particularly with IM seems to be affected resulting in poorer response or loss of response, as it is taken on an empty stomach. Less if any impact with the others if taken on a fully stomach.

So let's break down this case. Stopping IM for a couple of days around surgery is probably correct and has no implications. If a sleeve gastroplasty is the consideration, then resuming the IM with not changes is appropriate.

If the by-pass is the consideration, then changes probably should be made. She is already on a reduced dose of IM and the surgery will quite possibly impact on the absorption. There are two options. If IM is to continued, I would recommend increasing the dose back to 400 and monitoring response very closely over the next 3-6 months to see if the response can be maintained. Otherwise, a switch to one of the 2G TKIs should be entertained, the choice based on co-morbidities and availability.

I agree with Dr Lipton’s comments. The type of surgery matters and may interfere with absorption and efficacy of the TKI. I had a patient who performed bariatric surgery (by-pass) before the CML diagnosis. He never achieved cytogenetic or molecular response, with imatinib, dasatinib or nilotinib.