Need some perspective

41 M, dx with stage 2 right-sided colorectal cancer in the beginning of May 2026. Could be stage 3, hard to know without surgery, but we at least know it's local. I also have ulcerative colitis (UC). Here is my situation...

My cancer is dMMR/MSI-H (MLH1). The surgery team said they can't just do a resection because the reconnection may leak due to active colitis, so instead they must do a total colectomy (total colon removal) and ileostomy. Bowel biopsies from all other parts of my colon show no cancer, it's just at that right-sided spot. I think a total colectomy is drastic.

First oncologist I spoke to completely rejected the idea of neoadjuvant immunotherapy (IO) because it's "an absolute contraindication if you already have colitis." This is because colitis itself is a possible side effect of IO. However, she was unwilling to think creatively at all about how to many control the colitis so I could at least try IO. My right to try was rejected.

Second oncologist I spoke to was willing to do IO if I got on a biologic for UC that specifically suppresses a UC pathway in the bowel, but would have no effect on IO. He said a lot of IO patients use this biologic if the IO causes colitis. My UC is not currently severe. It's moderate in the rectum and mild in the rest of the bowel. Over time it continues to downgrade. Before my diagnosis, I was actually coming off prednisone because the flare was ending... but the hospital interventions made it all flare up again (IV antibiotics, colonoscopy, etc).

If they could offer me a resection, I would get that tomorrow... but I have decided to reject a total colectomy given that the cancer is MSI-H. I feel I should at least try IO to maybe save my bowel.

Here is the catch...

It took weeks to get approval for the biologic (Entyvio). I just got the first dose. Those few weeks were lost time. The loading doses for the biologic are week 0, 2 and 6. My UC has to get under control within that time for IO to be attempted. All the while, the cancer could be progressing. I am getting another CT scan (with two forms of contrast) on Monday to assess if there is progression. I was lucky to catch the cancer when it was still a local tumor... and this was because it was causing acute pain. Otherwise I would've had no idea.

I'm just wondering if anyone here has experience dealing with colorectal cancer through neoadjuvant therapy alone, especially MSI-H? I think if I didn't have the MSI-H mutation, I would just let them take my bowel. Furthermore, if IO doesn't eliminate the tumor but only shrinks it, I'll still be stuck with the same surgery options.

Could I please get some perspective? I know what I'm doing is not standard of care but my current medical team says it's an okay strategy. They just think it's sad that no surgeon would be willing to do just a resection.