"Doctor, I keep seeing blood in my stool—is it bowel cancer?" "I heard colonoscopy is very painful—can I skip it?" Colorectal cancer is China's 2nd most common and 3rd deadliest cancer; over 560,000 new cases and 280,000 deaths yearly, with nearly 60% diagnosed at mid-to-advanced stage. Colorectal cancer is the only major cancer that can be made "preventable and treatable" through screening—colonoscopy is the gold standard. This guide helps you overcome myths and protect your bowel health.
Colonoscopy uses a flexible tube with a tiny camera and instruments, inserted via the anus to examine the full rectum and colon. It can detect polyps, inflammation, ulcers, or cancer and is the only method that both finds and treats: benign polyps can be removed during the exam (80–95% of colorectal cancers arise from adenomatous polyps over 5–10 years); suspicious lesions can be biopsied. Three reasons it is the gold standard: very high detection—WHO data show >95% for cancer and ~90% for precancerous polyps, far above fecal occult blood (60–70%); early detection and treatment—2024 Chinese guidelines show early disease 5-year survival >90% vs mid-to-advanced <30%; cost-effective—single exam about 300–800 RMB, removing polyps can avoid much higher treatment costs later.
Core high-risk (must screen): adults ≥40 years—first colonoscopy recommended (current Chinese guideline); first-degree relatives with colorectal cancer or adenomatous polyps—start 10 years before relative's diagnosis age, every 3–5 years; recurrent rectal bleeding, abdominal pain, bloating, alternating diarrhea/constipation, narrow stools, unexplained weight loss, or anemia—get colonoscopy promptly. Other high-risk (recommended): long-term smoking/drinking, high-fat low-fiber diet, sedentary; ulcerative colitis, Crohn's, or prior polyps (especially adenomatous)—annual colonoscopy; long-term aspirin or NSAIDs—consider regular screening.
Before: 1–2 days—avoid high-fiber, hard-to-digest, colored foods (vegetables, fruit, grains, meat, blood products, dark drinks); eat white rice, noodles, tofu, egg custard. 6–8 hours before—take bowel prep (e.g. polyethylene glycol) per doctor, drink 2000–3000 ml until stools are clear; disclose medical history, allergies, and medications; if sedation—fast 6 hours, no water, bring a companion. During: standard exam may cause mild bloating or cramping; breathe deeply and relax; about 15–30 minutes. Sedated exam—you sleep through it, 20–40 minutes. Polyps or lesions may be removed or biopsied. After: mild gas and bloating often resolve in 1–2 hours; eat light, digestible food; if sedated—observe 30 minutes, no driving or alcohol for 24 hours. Seek care for severe pain, heavy bleeding, or fever.
Myth 1: No symptoms, no need—wrong. ~70% of early colorectal cancer has no clear symptoms; by the time of bleeding or pain, many are already mid-to-advanced. Myth 2: Colonoscopy is very painful—wrong. Modern scopes are thinner and softer; most tolerate it; sedation is available (extra ~300–500 RMB) for a pain-free exam. Myth 3: Normal fecal occult blood means no colonoscopy—wrong. Fecal tests miss ~30–40% of early cancer or polyps; they are screening only, not a substitute; positive result requires colonoscopy. Myth 4: One exam for life—wrong. Intervals depend on findings and risk: normal and low risk every 5–10 years; small benign polyps (<1 cm, <3) every 3–5 years; adenomatous or larger/multiple polyps annually; family history or bowel disease every 3–5 years or per doctor.
Side effects or bowel damage? Safe and minimally invasive; minor bloating or gas for 1–2 hours is common; perforation or bleeding is very rare (<0.1%). Does sedation harm or affect memory? Short-acting IV sedation clears quickly; no lasting harm or memory impact; mild dizziness may last ~30 minutes, full recovery within 24 hours. Can pregnant women or elderly have it? Pregnancy—caution; only if clearly indicated and after assessment; avoid prep and sedation that could affect the fetus. Elderly 70+ in good health can usually have it; serious conditions need doctor assessment. Stop blood pressure or diabetes drugs? Blood pressure drugs—no, take as usual. Diabetes drugs/insulin—adjust per doctor; if fasting, often hold to avoid low blood sugar, resume with meals. Other screening besides colonoscopy? Fecal occult blood (initial screen, lower detection), fecal DNA (~80% detection), CT colonography (when colonoscopy not possible). Colonoscopy remains first choice; discuss alternatives with your doctor if needed.
Colorectal cancer is not invincible—neglecting screening is. It is the only major cancer that can be caught early and treated effectively through screening; colonoscopy is the most effective tool. People ≥40, with family history or bowel symptoms, should get screened and follow the recommended interval; good bowel prep, cooperation during the exam, and simple aftercare make it manageable. This guide is for information only. One step earlier, far from fatal risk.
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