Is it even possible to develop colon cancer less than a year after undergoing a colonoscopy with no findings?

Good day,

Logically, I personally do not believe that cancer can develop in the large bowel of a person who underwent a colonoscopy with no findings 10 months after the procedure, let alone a person who underwent a colonoscopy with no findings 10 months after the procedure who is in their thirties and who recently underwent an abdominal and a pelvic CT scan (with no contrast) with no findings, but I am obviously not a specialist.

And I am aware that the members on this forum aren't specialists either, so it is not a professional opinion that I seek, but merely opinions.

Thank you in advance to those who will take the time to share theirs.

I genuinely appreciate it.

[Hozai]

Apparently it takes over 10 years for a polyp to turn into a cancer. So I personally also think it’s impossible.

I have another question. If someone has had bleeding for over 5 years and worries they have colon cancer. Haven’t not had a colonoscopy due to young age and Covid cancellation, but a recent CT scan of Abdomen and Pelvis with contrast shows no findings. Is it likely that a CT scan would miss it considering the symptoms have been going for over 5 years?

[Hidden in reply to Hozai]

Thank you for the response, Hozai.

I was already aware of the time it takes for a precancerous polyp to evolve into a malignant tumor, but wondering if cancer in the colon could develop via an alternate manner and, if so, plausible within 10 months following a colonoscopy without findings.

As for your question, if a person bleeds for over 5 years due to untreated colon cancer, they would have been dead or, at the very least, anemic by now. Moreover, other symptoms would have presented themselves.

Not to mention, the cancer would have spread to other organs.

And a CT scan with contrast of the abdomen and pelvis would not have missed a metastasis of the liver.

An internal hemorrhoid would make much more sense.

[Hozai in reply to Hidden]

No worries! As far as I’m aware. Researchers have come to a conclusion that 95% of colorectal cancers begin as polyps. There hasn’t been any literature on any other causes. I remember reading that 1% of polyps are cancerous and 95% of cancers start of as polyps.

Back to the the 5 years + of bleeding. The cause of concern is that it’s also associated with loose/narrow and thin stools. No pain or cramps like for IBD. And there has been a rectal finger test carried out that was negative for hemorrhoids. Apparently internal hemmorrhoids would felt? What else could these symptoms be? A polyp that might have turn cancerous by now?

[Itslaterthanyouthink in reply to Hozai]

My husband had a negative CT scan six years before being diagnosed with stage 4 bowel cancer, so his must have either been missed on that scan, or it developed and spread unusually quickly. When I tried to bring this up with his oncologist, he was evasive and I didn't really get an answer. Hubby often saw traces of blood on toilet paper but not enough to cause anaemia. His stools were also narrow. On finger examination, his GP told him he had haemorrhoids. I'm very confused!

[Hidden in reply to Itslaterthanyouthink]

I am sorry to hear about your husband's bowel cancer diagnosis.

From what I know, a CT scan is not an effective test for diagnosing polyps, so perhaps he had one that turned malignant within those six years. Aggressive cancers can develop and spread quickly. Perhaps the hemorrhoid that was felt upon rectal examination was, in fact, the polyp/tumor.

How old was your husband at the time of diagnosis?

And what led to his eventual diagnosis?

[Digger0 in reply to Hidden]

Agreed - I asked if I could have a CT scan instead of a colonoscopy but they said that it would not pick up small polyps.

[Hidden in reply to Hozai]

Because internal hemorrhoids can be too soft to be felt/diagnosed via rectal examination, the only way to know for sure is undergoing a scope procedure (ie: anoscopy, proctoscopy, sigmoidoscopy, colonoscopy).

Internal hemorrhoids could cause thin stools if they are big enough.

Do the bowel movement alternate or are they always loose and thin?

And, aside from the aforementioned symptoms, are there others?

[Hozai in reply to Hidden]

Also very sorry about your husbands diagnosis. Although I’m somewhat very anxious now as I’m scheduled to have a sigmoidoscopy either tomorrow or Friday. I kind of had my hopes up that I had a negative CT scan and reading your message makes me really worried again.

Bowel movements alternate. Sometimes they are firm and solid like usual. Other times ribbon like or loose.

Nope, no other symptoms.

I’m almost 100% certain that a negative colonoscopy and a clear CT would not miss out a cancer. Please reassure your friend, they would be the first ever as far as I’m aware. Due to my high stress I’ve spent a good part of 3 months reading hundreds of patient stories and research pages to know that that wouldn’t be possible.

[Hozai in reply to Hozai]

So I done my flexi sigmoidoscopy today. No findings at all, not even internal haemorrhoids. Very strange. Is a flexi sig and a CT now enough or shall I push for a full colonoscopy?

[Itslaterthanyouthink]

Personally, I think it's highly unlikely unless you have Lynch Syndrome (and I don't know enough about this to know whether it's likely, even then). This suggests that something was missed on the colonoscopy or the diagnosis is incorrect. I hope for your sake, it's the latter.

[Hidden in reply to Itslaterthanyouthink]

Thank you for the reply, Itslaterthanyouthink.

I did not make this post for myself, but for someone who does not have access to the Internet at the moment.

And not only do they not have Lynch Syndrome, but they were not sedated while undergoing the colonoscopy, watching the entire procedure being performed on the screen, seeing what the gastroenterologist was seeing (polyps and tumors standout).

Could collateral cancer really be missed during a colonoscopy, the gold standard for diagnosing it?

And let's say hypothetically that it was, wouldn't an ultrasound and/or a CT scan of the abdomen and pelvis and/or a complete blood count detect *something* 10 months later?

[Itslaterthanyouthink]

I don't have the answers to any of these questions and am probably more confused than you are. I hope you find answers - let us know if you do.

[digar]

Similar situation. Two months ago I had a normal colonoscopy and no polyps, but I continue to bleed and have constipation. Anyone know what this could be? The doc didn’t mention I had hemorrhoids or anal fissure, but would he be able to see these in a colonoscopy anyway? Still worried with no peace of mind yet until I get to the bottom of the cause of this bleeding and constipation.