Colonoscopy: What the Prep Actually Involves, and What the Report Means
Colonoscopy is the definitive test for lower GI symptoms and the gold standard for colorectal cancer screening. It is also the test Indian patients delay longest, often out of prep discomfort or embarrassment. Understanding what the day looks like and what the report actually says reduces both barriers substantially.
The day-before prep
- Low-fibre diet for 2-3 days before (no seeds, nuts, whole grains, raw vegetables).
- Clear liquid diet the full day before (broth, clear juice, water, tea without milk).
- Prep solution taken evening before and/or early morning of test — 2-4 litres over hours.
- Frequent bowel movements starting 1-2 hours after prep begins.
- Stop iron supplements 5-7 days before (they discolour the bowel).
- Blood thinners often need adjustment — discuss with the doctor 1-2 weeks before.
The procedure itself
- Sedation is standard in most Indian centres now (conscious sedation with midazolam + fentanyl, or propofol).
- Duration 20-45 minutes.
- Biopsies taken if any suspicious area seen.
- Polyps removed if seen and small enough.
- Discharged same day, but sedation prevents driving for 24 hours.
The report categories
- Finding: Normal colonoscopy · Meaning: No polyps, no inflammation, no mass · Typical follow-up: Repeat in 10 years for screening
- Finding: Small hyperplastic polyps removed · Meaning: Almost always benign · Typical follow-up: Repeat in 5-10 years
- Finding: Adenomatous polyps removed (< 1 cm, low grade) · Meaning: Precancerous but low-risk · Typical follow-up: Repeat in 5 years
- Finding: Large adenoma or high-grade dysplasia · Meaning: Higher precancerous risk · Typical follow-up: Repeat in 3 years
- Finding: Adenocarcinoma · Meaning: Colorectal cancer · Typical follow-up: Referral to oncology
- Finding: Inflammatory changes · Meaning: Colitis (multiple causes) · Typical follow-up: Biopsy interpretation guides next step
- Finding: Haemorrhoids · Meaning: Common, usually incidental · Typical follow-up: Managed conservatively unless symptomatic
- Finding: Diverticulosis · Meaning: Small pouches; common in elderly · Typical follow-up: Dietary advice, no specific treatment
Who should have one
- Everyone from age 50 as screening (age 45 in some guidelines).
- Anyone with a first-degree relative with colorectal cancer, starting 10 years earlier than that relative's diagnosis.
- Anyone with rectal bleeding, especially if new or persistent.
- Anyone with change in bowel habits lasting > 6 weeks.
- Anyone with iron deficiency anaemia in men or postmenopausal women (until proven otherwise).
- Anyone with weight loss and GI symptoms.
The screening argument
Colon cancer is the second commonest cancer globally and increasingly common in Indian urban populations. A colonoscopy at 50 with negative findings and a repeat at 60 catches nearly all cases at a curable stage. The prep is unpleasant for a day; the alternative — presenting with symptomatic disease at 65 — is a much worse day.
Store the report AND the biopsy result (histopathology comes back 5-10 days later) in your record. The 10-year screening interval depends on both. A colonoscopy report without its histology attached is only half the record.
References
Free for 90 days, no card needed. After that, keeping the record costs ₹349 for the year.
General information, not medical advice. Always talk to a qualified doctor about your own care. Where this and your doctor disagree, your doctor is right.