Fit testing after pelvic RT

[Izzysdad]

I’m wondering if any RT patients went on to have false positives on the Fit test for colon cancer. I can’t find any studies or if any have been done. I’m due for regular screening but am hesitant if it’s going to start me down a lengthy road of testing because of radiation damage to my colon that is not related to colon cancer. In other words a false positive. My RT was 3 years ago and I’ve never seen any blood but the Fit finds it at a microscopic level. I should note I’m not at risk for colon cancer, it’s just recommended after age 45.

[PSAed]

I had RT about 4 years ago 39 fraction over 5 weeks I think it was. I also did 2 years of HT on Lupron. Anyway, I used the Bowel test kit (checks for blood in Poo ) I received in the post and got a positive result, I was advised to see my GP. He then referred me for a colonoscopy performed at my local hospital. I asked the Gastroenterologist to also "have a look as she was there 🙄 " for radiation damage from my APCa treatment.

She found and removed 4 Polyps and told me afterwards I had "very mild radiation Proctitis. I do not have any bowel movement issues. Overall she done a great job and I'm delighted with the results.

If you get a positive result on the FIT test ,think very carefully before you ignore it!!

[Izzysdad in reply to PSAed]

I wouldn’t ignore it. I was just interested in others experiences as to whether radiation damage caused a false positive. In your case that would seem not to be the case. I’m not adverse to doing the test. Just concerned that the radiation may make a positive result a foregone conclusion leading to unnecessary further testing. Thanks for relating your experience.

[pd63]

Fit test is not for cancer diagnosis it checks for blood in the faeces, the standard test for colon cancer is a colonoscopy.Blood in the poo can be for many reasons, many are not serious.

[Izzysdad in reply to pd63]

yes I know that. I guess my post wasn’t clear. I’m interested in hearing from anyone who had RT then had a positive Fit test that a subsequent colonoscopy revealed was the result of radiation damage rather than cancer, polyps etc. in short, is there any point to bothering with a Fit or should I just go straight to a colonoscopy to get things checked out.

[Jack54]

I’m 70. Diagnosed Gleason 9 in March 2020. Did 18 months ADT and 45 tx EBRT. Finished radiation October 2020. Had colonoscopy April 2024 and doctor found one precancerous polp along with some mild proctitis.

[Izzysdad in reply to Jack54]

thanks for your response. I’ve considered yours and PSAed’s comments and am thinking there is no real downside to doing the test. Maybe I’ll get a faster colonoscopy, if it comes back positive, and they can tell me the extent of damage in there from the RT. Always good to look at things from a different angle.

[Jack54 in reply to Izzysdad]

Approximately one year after RT my stools began being soft. It was like trying to wipe a sharpie. Couldn’t get clean. Was told that the radiation did some damage to the lining of the colon and the colon no longer absorbed water as it did before RT. So I started using a panty liner to keep from getting brown streaks on my underwear.

[Izzysdad in reply to Jack54]

Wet wipes and/or showering after the morning “sit down” is the answer to that.

[Jack54 in reply to Izzysdad]

I’ve tried that. The problem with showering after every sit is impossible. Since I don’t sit at the same time each day. I work two jobs and it’s difficult. I use wet wipes after every sit. I use about 4-5 wipes each time and still can’t get clean. It’s like a never ending paste.

[MarkS]

I've just completed 37 sessions of RT. I received a poo test and rang the helpline. They suggested I discuss it with my oncologist and said that the poo test had a shelf life of 1 year so no rush. I did discuss it with my oncologist who suggested waiting at least 3-4 months after RT. So I intend to do it in about 6 months.

[Izzysdad in reply to MarkS]

Thanks for your input. Its nice your oncologist gave you some advice. I asked mine and he said go ask my GP. The last question I asked him he referred me to the clinic pharmacist. This doctor is the literal definition of “specialist”. Never ventures outside his guardrails. I figure I’ll go for it. No real downside.