Cologuard positive. Can I have a colonoscopy 8 months after radiation?

I put off my colonoscopy for a few years because last time I had them they were done without sedating you, they just raw-dog you right there on a table and it SUUUUUUCCCCCCCKKKKKKKKEEEEEDDD!

Due to that experience, I kept putting it off and did a couple different variations of the stick test - Cologuard and some other one that didn't require such a large, um, "sample". Last year it came back positive so I got my colonoscopy and there were nothing but a couple polyps that they removed.

When talking to my gastroenterologist, he said both of those tests aren't particularly accurate but might indicate an irregularity. Its analogous to the PSA test - not a true signal of cancer but more of a "check engine light".

I put off my colonoscopy for a few years because last time I had them they were done without sedating you, they just raw-dog you right there on a table and it SUUUUUUCCCCCCCKKKKKKKKEEEEEDDD!

Due to that experience, I kept putting it off and did a couple different variations of the stick test - Cologuard and some other one that didn't require such a large, um, "sample". Last year it came back positive so I got my colonoscopy and there were nothing but a couple polyps that they removed.

When talking to my gastroenterologist, he said both of those tests aren't particularly accurate but might indicate an irregularity. Its analogous to the PSA test - not a true signal of cancer but more of a "check engine light".

@johnny8924
If I read right you had IMRT. I believe that is internal type of radiation like pellets. Is that correct?

I had external beam radiation (proton). Thus no personal experience with IMRT. I am not sure if same radiation damage to colon is different with IRMT so can't comment on IMRT.

The colon is going to get some radiation damage from external radiation. It is why patients have the Space/Oar of balloon done to move colon away from prostate. The colon is right on top of prostate. So if R/O is treating your prostate and margins the radiation beam most likely will hit colon.

Per my R/Os what happens is the blood vessels in colon are damaged. The body will build new ones but are quite fragile and easily bleed with bowel movements. The new blood vessels over time become stronger and the bleeding will stop.

The amount of radiation the colon receives and cause damage to it also along with very sensitive. It is why colonoscopies requirement within 3 years is done at UFHPTI. So the need to have follow up colonoscopies within 3 years of ending radiation treatments is not there.

I had colonoscopy many years ago prior to my radiation treatments. I was due one at the 10 year mark. UFHPTI required I get one prior to radiation. At that colonoscopy they did find polyps and removed 3 of them. So the surgery to do this was not with a very highly irritated and damaged colon so you can see why the recommendations to have prior to radiation if you are due one within 3 years of radiation treatments (UFHPTI).

I will have to have another colonoscopy in 5 years not 10 years because of the polyps. I was told my PCP would set this up for me and would be on my patient information. I do not understand some post of those over 70 being told no colonoscopies after 70.

I was 76 when I had my last one and will be 81 when I was told will have my next one. The most common reason for doing colonoscopies is to remove pre cancerous polyps so they won't grow into cancer and to look for signs of bleeding brought to doctors attention that bleeding maybe present in body. (my Mayo doctors not me information).

@jc76
I did 28 sessions of IMRT external beam radiation which is a common treatment for prostate cancer, ending in April 2025. I also had a Barrigel spacer to minimize the side effects of the radiation to the colon and rectum.

@johnny8924
Can you give me the IMRT written out. I know the RT is radiation therapy.

I thought that meant internal. I had external beam proton radiation treatment (30 rounds with Space/Oar, markers).

I am probably wrong and why I thought you had internal with the "I." Won't be first time but don't have Colleen's abbreviation list available and you explaining what the IMRT would be helpful so don't make same mistake again.

@jc76
Here's a good description of IMRT.
https://www.mayoclinic.org/tests-procedures/intensity-modulated-radiation-therapy/about/pac-20385147

I wasn't aware of the general prohibition against colonoscopies within one year of radiation.

With that being said, I had one four months after radiation and the process went well.