Colorectal Cancer: From a Lifestyle-Related Disease to a Preventable Cancer

Colorectal cancer is rising in China, but it is also one of the major cancers with a clear opportunity for prevention. Many cases develop slowly from precancerous polyps over several years. Screening can find and remove these lesions before cancer forms, or detect cancer at an earlier and more treatable stage.

The most important message is not that colorectal cancer is simply a “disease of affluence.” Genetics, age, inflammatory bowel disease, lifestyle, and access to screening all matter. Prevention works best when healthy habits are combined with a structured screening plan rather than relying on symptoms.

Why Colorectal Cancer Is Increasing

China’s colorectal cancer burden has grown alongside population aging, urbanization, changing diets, reduced physical activity, obesity, smoking, alcohol use, and metabolic disease. Diets high in processed meat and excessive red meat, and low in fiber-rich foods, are associated with increased risk. These factors do not explain every case, and people with a healthy lifestyle can still develop colorectal cancer.

Important risk factors include:

• Increasing age;
• A personal history of colorectal polyps or cancer;
• A parent, sibling, or child with colorectal cancer or advanced polyps;
• Inherited syndromes such as Lynch syndrome or familial adenomatous polyposis;
• Long-standing ulcerative colitis or Crohn’s colitis;
• Smoking, heavy alcohol use, obesity, and physical inactivity;
• Type 2 diabetes and other metabolic risk factors.

For a broader review of diagnosis and treatment, read our complete colorectal cancer guide for international patients in Shanghai.

The Adenoma-to-Cancer Sequence: A Window for Prevention

Many colorectal cancers begin as adenomatous polyps or certain serrated lesions. These growths can acquire cellular changes over time and eventually become invasive cancer. The process often takes years, creating a valuable window for detection and removal.

Not every polyp will become cancer. Risk depends on size, number, microscopic features, location, and whether the lesion was removed completely. After polypectomy, the next colonoscopy interval should be based on the pathology report, bowel preparation quality, completeness of the examination, family history, and previous findings.

This is why colorectal screening can do more than detect cancer early. Colonoscopy can interrupt the process before cancer develops.

Do Not Wait for Symptoms

Early colorectal cancer may cause no symptoms. When symptoms do occur, they can include blood in the stool, persistent changes in bowel habits, unexplained iron-deficiency anemia, abdominal pain, narrowing of the stool, weight loss, or a feeling that the bowel has not emptied completely.

Bright red bleeding is often attributed to hemorrhoids, but visible blood should not automatically be dismissed. Black stool, heavy bleeding, severe abdominal pain, vomiting, inability to pass stool or gas, fainting, or rapid deterioration requires urgent medical attention.

Screening Options: Colonoscopy and Noninvasive Tests

The best screening test is one that is medically appropriate and actually completed. Starting age and frequency depend on national guidance, personal risk, family history, and previous results. People with symptoms or high-risk conditions need diagnostic evaluation rather than routine average-risk screening.

Colonoscopy

Colonoscopy is the most comprehensive screening method because it allows the doctor to inspect the full colon, biopsy abnormalities, and remove many polyps during the same procedure. Its quality depends on adequate bowel preparation, complete examination, careful withdrawal technique, and an experienced endoscopy team.

Colonoscopy is invasive and requires preparation and usually sedation. Complications such as bleeding or perforation are uncommon but possible, especially after removal of larger lesions.

Fecal Immunochemical Testing

FIT detects small amounts of human blood in stool and can be repeated at regular intervals. It is convenient and noninvasive, but a negative result does not rule out all cancers or advanced polyps. Any positive result requires timely colonoscopy.

Stool DNA Testing

Stool DNA tests combine blood detection with selected molecular markers. They can improve sensitivity for some cancers compared with blood-only stool testing, but they may produce more false-positive results, cost more, and still require colonoscopy after an abnormal result. Availability varies by country.

CT Colonography and Other Methods

CT colonography may be an alternative for selected patients, but bowel preparation is still needed, radiation is involved, and a colonoscopy is required if a significant lesion is found. Blood-based screening tests are developing, but they should not be assumed to replace established methods without specialist guidance.

Explore our feature on colorectal cancer screening and early detection in Shanghai.

After an Abnormal Screening Result

An abnormal stool test is not a cancer diagnosis. It means the patient needs colonoscopy to identify the source. Repeating the stool test instead of arranging colonoscopy can delay diagnosis.

If a suspicious mass is found, biopsy confirms the pathology. Staging may include contrast-enhanced CT of the chest, abdomen, and pelvis. Rectal cancer often requires high-quality pelvic MRI, and sometimes endorectal ultrasound, to assess local depth, lymph nodes, and the relationship to the anal sphincter.

CEA can help monitor selected diagnosed patients but is not accurate enough to serve as a stand-alone screening or diagnostic test.

Minimally Invasive Surgery: Cancer Control Comes First

Surgery is central to treatment for localized colon and rectal cancer. Depending on the case, it may be performed through an open, laparoscopic, or robotic approach. Minimally invasive surgery can reduce incision-related trauma and support faster recovery for suitable patients, but the method must never compromise complete tumor removal, adequate margins, or proper lymph-node assessment.

For colon cancer, complete mesocolic excision principles may guide removal of the tumor and its lymphovascular drainage. For rectal cancer, total mesorectal excision is a core surgical technique. The quality of the operation and pathology assessment is more important than the size of the incision alone.

Sphincter Preservation: Protecting Quality of Life Safely

For low rectal cancer, patients naturally worry about a permanent stoma. Modern imaging, neoadjuvant treatment, precise pelvic surgery, stapling techniques, transanal approaches, and reconstruction can make sphincter preservation possible for more patients.

Preservation is not appropriate at any cost. Tumor involvement of the anal sphincter, poor function before treatment, inability to obtain safe margins, and other anatomical factors may make a permanent stoma the safer choice. A temporary diverting stoma may also be recommended to protect a low anastomosis while it heals.

Even after successful sphincter-preserving surgery, bowel frequency, urgency, clustering, or leakage can occur. This is known as low anterior resection syndrome and should be managed with diet, medication, pelvic-floor rehabilitation, and specialist follow-up.

Our rectal cancer sphincter-preservation case illustrates how cancer control and quality of life can be considered together.

Shanghai Expertise: Fudan’s Colorectal Surgery Team

Fudan University Shanghai Cancer Center has developed a specialist colorectal cancer platform integrating surgery, medical oncology, radiation oncology, endoscopy, imaging, pathology, genetics, and rehabilitation.

The colorectal surgery team led by Prof. Cai Sanjun has contributed to standardized rectal cancer surgery, multidisciplinary treatment, sphincter-preserving strategies, and the management of complex and recurrent disease. The center’s value lies not only in surgical volume, but also in coordinated staging and treatment sequencing.

Learn more about Prof. Cai Sanjun and colorectal cancer care at Fudan University Shanghai Cancer Center.

Rectal Cancer: Why Treatment Often Begins Before Surgery

Locally advanced rectal cancer may be treated with chemotherapy, radiotherapy, or both before surgery. Total neoadjuvant therapy places more systemic treatment before the operation and can improve completion rates, tumor response, and control of distant disease in selected patients.

Patients with an apparent complete clinical response may sometimes enter a highly structured watch-and-wait program instead of immediate surgery. This is not the same as being cured or receiving no care. It requires expert reassessment with examination, endoscopy, MRI, and frequent surveillance, with salvage surgery available if the tumor regrows.

Precision Treatment: MSI-H and Immunotherapy

Colorectal tumors should be evaluated for mismatch repair deficiency or microsatellite instability when clinically appropriate. MSI-H or dMMR status can suggest Lynch syndrome, influence prognosis, and predict a greater likelihood of response to immune checkpoint inhibitors in advanced disease.

Immunotherapy has produced deep and durable responses in many patients with metastatic MSI-H/dMMR colorectal cancer. It is also being studied and used in selected localized settings under specialist protocols. These results are highly encouraging, but they apply to a minority of colorectal cancers and should not be generalized to microsatellite-stable disease.

Additional molecular testing in advanced disease may include RAS, BRAF, HER2, NTRK, and other markers that guide targeted treatment or clinical-trial eligibility. Tumor location and previous therapy also affect treatment selection.

Inherited Risk and Family Screening

Genetic counseling should be considered when colorectal cancer occurs at a young age, multiple relatives are affected, there are related cancers in the family, tumor testing suggests Lynch syndrome, or numerous polyps are found.

A confirmed inherited syndrome can change surgery, surveillance, and screening recommendations for relatives. Family members should not simply copy the patient’s schedule; they need risk-based advice from genetics and gastroenterology professionals.

Recovery and Long-Term Follow-Up

Recovery includes more than wound healing. Patients may need support for bowel function, stoma care, nutrition, physical strength, sexual and urinary function, neuropathy, anxiety, and return to work.

A survivorship plan may include:

• Clinical review and CEA monitoring when appropriate;
• Scheduled CT imaging based on stage and treatment;
• Colonoscopy after treatment and at individualized intervals;
• Management of bowel dysfunction and pelvic-floor rehabilitation;
• Stoma education and discussion of reversal when medically suitable;
• Regular physical activity and a fiber-rich diet when tolerated;
• Reduced processed meat, smoking cessation, and moderation or avoidance of alcohol;
• Family-risk assessment and genetic counseling when indicated.

How CMCS Supports International Patients in Shanghai

China Medical Concierge Shanghai (CMCS) is a health management and medical concierge company, not a hospital. We help international patients organize medical information, identify appropriate specialists in Shanghai, and coordinate care before, during, and after appointments.

Depending on the case, CMCS can assist with:

• Organizing colonoscopy, pathology, CT, pelvic MRI, molecular tests, operative records, and previous treatment details;
• Coordinating evaluation by colorectal surgery, medical oncology, radiation oncology, gastroenterology, genetics, rehabilitation, or a multidisciplinary team;
• Preparing a concise bilingual case summary and prioritized consultation questions;
• Supporting appointment planning, travel preparation, on-site communication, and examination scheduling;
• Helping patients track neoadjuvant treatment, surgery, stoma care, bowel rehabilitation, and surveillance milestones;
• Facilitating necessary communication with family members after receiving the patient’s authorization.

Remote record review or video consultation requires the physician’s approval and may not replace an in-person examination. Patients should provide authorization and complete, recent medical records before case coordination. CMCS can usually address approximately three to five core questions during initial screening. If specific medical coordination is required, the service scope and applicable fee will be explained in advance.

Conclusion: Screening Is the Strongest Prevention Tool

Colorectal cancer often provides a longer prevention window than many other cancers. Healthy habits can reduce risk, but screening is what allows doctors to find bleeding, advanced polyps, and early cancers before symptoms appear.

Shanghai teams are helping move care from late symptom-driven diagnosis toward standardized screening, high-quality colonoscopy, precise surgery, organ preservation, molecular classification, and lifelong follow-up. The most effective cancer treatment may begin years before cancer develops, with one completed screening test.

Contact CMCS

For help organizing colorectal cancer records, connecting with appropriate specialists in Shanghai, or planning a medical visit, contact us:

• Website: www.medicalsh.com
• Email: contract@medicalsh.com
• WhatsApp: https://wa.me/message/3AM6KAGCW2BAD1

You may also submit your information through our contact page.

Medical notice: This article is for health education only and does not provide a diagnosis or individualized treatment advice. Screening, colonoscopy, surgery, chemotherapy, radiotherapy, immunotherapy, genetic testing, and follow-up plans must be determined by qualified physicians using the patient’s complete medical information.