When it comes to cancer, its ability to be ‘silent’ and asymptomatic in most cases is what makes it dangerous. Another worrying aspect is that it can be misdiagnosed.
Our digestive system is complex and is susceptible to several gastrointestinal issues. A stomach pain, bloating and episodes of diarrhoea may not seem concerning until it turns out to be colorectal cancer. The cancer can be mistaken for digestive issues, such as Irritable Bowel Syndrome (IBS), haemorrhoids, or Inflammatory Bowel Disease (IBD), due to similar symptoms like changes in bowel habits, abdominal pain, and rectal bleeding. So how do we differentiate between them? Dr Vivek Mangla, Director-Gastrointestinal and Hepatopancreatobiliary, Surgical Oncology, Max Super Speciality Hospital, Patparganj, shares the answer.
What Is Colorectal Cancer?
Colorectal cancer is a type of cancer that originates in the colon, which is the large intestine, or rectum. It usually begins as a growth called a polyp, which can be non-cancerous (benign) or potentially develop into cancer (malignant) over time. If left untreated, the cancer cells can invade and spread to other parts of the body.
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According to the World Health Organization (WHO), more than 10 lakh new cases of colorectal cancer and more than 9.3 lakh colorectal cancer deaths were estimated to have occurred in 2020, worldwide.
In India, the annual incidence rates (AAR) for colon cancer and rectal cancer in men are 4.4 and 4.1 per 100000, respectively, says the Indian Council of Medical Research (ICMR), adding, "The AAR for colon cancer in women is 3.9 per 100000. Colon cancer ranks 8th and rectal cancer ranks 9th among men."
How To Distinguish Between Colorectal Cancer And Common Gastrointestinal Disorders
Speaking of the distinguishing factors, Dr Mangla says, “Colorectal cancer is a disease that mostly affects people above the age of 50 years, although its incidence is increasing in the young.” He adds, “Colorectal cancer remains asymptomatic for a long duration in its course and symptoms only appear later. Other GI diseases generally present with symptoms early in their course.”
IBD, including Crohn’s disease and ulcerative colitis can affect people during their childhood, and present with dramatic symptoms of diarrhoea, rectal bleeding and weight loss, according to the doctor.
In addition, IBS presents with diarrhoea and white mucoid discharge which is NOT seen in colorectal cancer. “It generally does not present with rectal bleeding, but cramps can be confusing. Haemorrhoids present with painless bright red bleed during defecation, with stools different from the bleed which is in contrast to colorectal cancer where blood can be red or maroon but is mixed with stools,” he explains.
But the doctor also mentions that at times, these clinical differences can be very subtle and can make differentiation based solely on clinical grounds difficult, thus needing other investigations.
Symptoms Of Colorectal Cancer
Here are some classic signs of colorectal cancer:
- Rectal bleeding
- Any change in consistency and type of stool (stools becoming narrower)
- Alternate diarrhoea and constipation
- Bowel fullness even after passing stools
- Abdominal cramps/pain
- Unintended weight loss
- Lethargy and tiredness
- Persistent, non resolving or worsening symptoms
Signs That Can Lead To A Misdiagnosis
According to Dr Mangla, bleeding per rectum, diarrhoea, constipation and abdominal pain are some symptoms which are common for nearly all lower GI disorders and can easily lead to misdiagnosis.
“Hence, when assessing any patient with GI symptoms, every step should be taken to rule out colorectal cancer in patients with suggestive symptoms,” she advises.
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Tests To Take
“The simplest test for diagnosing or ruling out colorectal cancer is the per-rectal examination and proctoscopy done in OPD which will reveal any growth or ulcer in the rectum,” says Dr Mangla, further recommending a complete colonoscopy after preparing the bowel. He says it is a must when colorectal cancer is a possibility to clearly visualise the whole of colon and rectum to rule out any growth, ulcer or polyps and take biopsy to confirm the diagnosis.
In addition, Contrast Enhanced Computed Tomography (CECT) chest and abdomen is the next step to be done to rule out any extracolonic disease with metastasis. “Colonoscopy may very well differentiate between other GI disorders too and help rule them out with any absence of colonic growth in IBS to findings of typical ulcers and mucosal picture in IBD. Other investigations like MRI pelvis, PET CT may be done in proven cases of colorectal cancer as needed,” Dr Mangla concludes.