Blood in stool could be early warning sign of colon polyps and colorectal cancer, doctors warn
New Delhi: For many people, spotting blood in the stool is an uncomfortable experience – one that is often brushed aside as a symptom of piles (haemorrhoids) or an anal fissure. While these remain among the most common causes of rectal bleeding, gastroenterologists are raising a crucial red flag: persistent or recurrent blood in the stool should never be self-diagnosed. In some cases, it could be the earliest sign of colon polyps, inflammatory bowel disease, ulcers or even colorectal cancer.
The warning comes at a time when colorectal cancer is increasingly becoming a global health concern, with cases rising among younger adults as well. According to the World Health Organization (WHO), early diagnosis and timely treatment significantly improve survival, while screening can even prevent colorectal cancer by identifying and removing precancerous polyps before they turn cancerous.
Against this backdrop, doctors are urging people not to ignore persistent rectal bleeding or changes in bowel habits, stressing that a simple colonoscopy can detect and often treat, many underlying conditions before they become life-threatening.
Blood in stool is not always Piles
Rectal bleeding is one of the most common complaints seen in gastroenterology and colorectal surgery clinics. Although piles and fissures account for a significant number of cases, they are far from the only causes.
Talking exclusively to News9 Live, Dr Advait Patankar, Endoscopist at Zen Multispeciality Hospital, explains that patients frequently delay medical consultation because of embarrassment or the assumption that the bleeding is harmless.
“Blood in stool is one of the most frequently encountered symptoms in the OPD, yet most assume it is always due to piles or fissures. Many avoid medical attention due to embarrassment or fear. While these are common causes, they are not the only explanations.”
He explains that persistent bleeding can also signal colon polyps, inflammatory conditions, ulcers, diverticular disease and even colorectal cancer, all of which require prompt medical evaluation.
Alarm symptoms that should never be ignored
Doctors say rectal bleeding becomes particularly concerning when it is accompanied by other symptoms.
These include:
- Persistent or recurrent blood in the stool
- A sudden change in bowel habits, including constipation or diarrhoea lasting several weeks
- Unexplained weight loss
- Persistent fatigue or low haemoglobin (iron-deficiency anaemia)
- Abdominal pain or bloating
- A family history of colorectal or other gastrointestinal cancers
The WHO also lists unexplained weight loss, persistent fatigue and iron-deficiency anaemia due to chronic blood loss among the important warning signs of colorectal cancer.
Dr Patankar adds: “A sudden change in bowel habits, persistent constipation or diarrhoea, unexplained weight loss, low haemoglobin levels, a family history of gastrointestinal cancer, or recurring blood in stool warrant thorough evaluation. This can also be due to polyps or other abnormal growths in the colon that have the potential to become cancerous if left untreated.”
Why colon polyps matter
One of the biggest reasons doctors recommend early investigation is because of colon polyps – small growths that develop on the lining of the large intestine.
While many polyps are benign, some types can gradually transform into colorectal cancer over several years. Fortunately, this progression is usually slow, creating a valuable opportunity for early detection and removal before cancer develops.
This is why colorectal cancer is considered one of the few cancers that can often be prevented, not just detected early, through regular screening and timely removal of precancerous polyps.
When blood appears in the stool, doctors often recommend a colonoscopy, considered the most accurate investigation for examining the colon and rectum.
The procedure involves inserting a thin, flexible tube fitted with a high-definition camera through the rectum to inspect the entire large intestine and the terminal part of the small intestine. It is usually performed under mild sedation, allowing patients to remain comfortable throughout.
Unlike CT scans or other imaging tests, colonoscopy offers a direct visual examination of the bowel lining, enabling doctors to identify tiny polyps, inflammation, ulcers or early cancers that may otherwise go unnoticed. It also allows tissue biopsy and removal of many precancerous polyps during the same procedure, making it both a diagnostic and therapeutic tool. Clinical guidelines continue to regard colonoscopy as the gold standard for colorectal evaluation and screening.
Colonoscopy can diagnose and treat at same time
While talking to News9 Live, Dr Priya Gupta, Anorectal Surgeon at Zen Multispeciality Hospital explains that colonoscopy offers benefits beyond diagnosis. “A colonoscopy is the gold standard test for blood in stools as it helps identify polyps, inflammation, ulcers, or tumours. These may not present with any other symptom except bleeding.”
She further explains that: “Most importantly, colonoscopy is not only for diagnosis, conditions like polyps or small piles can actually be treated during the colonoscopy itself. Over the years, increased awareness has helped patients with improved treatment results due to early diagnosis and timely intervention.”
This ability to both detect and remove precancerous lesions in a single procedure has made colonoscopy one of the most effective tools in reducing colorectal cancer incidence and mortality.
Doctors emphasise that not every episode of blood in the stool indicates cancer, and in many cases the cause is benign. However, assuming that rectal bleeding is “just piles” without proper medical evaluation can delay the diagnosis of potentially serious conditions.