Colon / Colorectal cancer
New constipation, diarrhea, thin stools, or incomplete emptying
Your bowels changed and stayed changed. New constipation (fewer than 3 movements a week when you used to have daily). New diarrhea lasting weeks. Stools that come out pencil-thin. The feeling that you never fully empty. Alternating between constipation and diarrhea without a dietary reason.
What it could mean
Persistent bowel changes lasting more than 3 weeks can signal a partial obstruction from a colorectal tumor. Thin stools especially — think of the tumor as narrowing the passage. Not all cancers cause thin stools, but the pattern is worth naming.
What it probably is (to be fair)
IBS, food sensitivities, medication changes (opioids constipate, antibiotics loosen), stress, or GI infections. These are far more common. But cancer hides among common things, which is why "just IBS" needs to be earned by workup, not assumed.
Why this gets dismissed
IBS is real, but it’s also the medical dumping ground for anything a doctor doesn’t want to work up. If you got an "IBS" diagnosis without a colonoscopy, stool testing, or celiac panel, you got a shrug in a diagnosis costume.
A proper workup for persistent bowel changes should include: stool tests for blood and inflammation markers (fecal immunochemical test, calprotectin), a celiac panel, and a colonoscopy if you’re over 45 or symptomatic. Anything less is triage, not diagnosis.
When to call your doctor
- Bowel changes that persist beyond 3 weeks without a clear cause
- New thin/pencil-shaped stools
- Persistent feeling of incomplete evacuation
- Bowel changes with unexplained weight loss or fatigue
- Bowel changes with rectal bleeding
When to go to the ER
- Complete inability to pass stool or gas for more than 24 hours with abdominal distension (possible obstruction)
- Severe abdominal pain with vomiting
- Bloody diarrhea with fever
If you're dismissed
If you’re told "it’s just IBS" without stool testing or (if appropriate) a scope, that’s not a diagnosis. Ask: "What have we ruled out? Can we do a FIT test and a calprotectin?" Both are cheap, non-invasive, and specifically screen for the things a shrug misses.
