Know yourself, know your enemy, and you will never be defeated
In this article:
Incidence and Mortality Statistics
Common Symptoms
Risk Factors
Diagnostic Methods
Treatment Methods
Personal Care
Read More
Prevalence in Hong Kong
Colorectal cancer is the third commonest cancer in Hong Kong. In 2022, there were 5 190 new cases, contributing to 14.7% of all new cancer cases in Hong Kong. Of these, 2 928 were male and 2 262 were female.
In 2022, the crude annual incidence rate of colorectal cancer was 71 per 100 000 Hong Kong population. The median age at diagnosis for males was 69 years and that for females was 69 years. The age-specific incidence rates increased significantly from age 50 onwards. Colorectal cancer is more common among males, reflected by the male to female ratio of about 1.3 to 1 in 2022. Colorectal cancer is the second leading cause of cancer deaths in Hong Kong. In 2022, a total of 2 270 people died from this cancer, accounting for 15.4% of all cancer deaths.
Colorectal cancer, if detected and treated early, is highly curable. Overall, the five-year relative survival rate was 58.2% for all stages combined. The rates were high for stage I (95.7%) and stage II (87.3%). It dropped to 68.7% for stage III and further declined to 9.3% for stage IV.
Early Symptoms of Colorectal Cancer
Common signs of colorectal cancer include:
Early-stage colorectal cancer may not show obvious symptoms. If any of the above symptoms appear, seek medical attention promptly for evaluation.
Understanding Cancer Causes
Bad lifestyle habits, especially diet, primarily cause colorectal cancer. Consuming excessive animal fats, insufficient fibre-rich fruits and vegetables, or frequent intake of grilled or processed meats increases the risk. Long-term lack of physical activity, smoking, and excessive alcohol consumption are also major contributors.
Moreover, personal medical history is another significant risk factor, as individuals with chronic intestinal inflammation or polyps face an elevated risk of developing colorectal cancer. The risk also increases for blood relatives such as siblings and children if there is a family history of colorectal cancer.
To mitigate these risks and prevent colorectal cancer, adopting a healthier lifestyle is essential. This involves increasing consumption of vitamin-, mineral- and fibre-rich fruits, vegetables and whole grains, limiting alcohol intake to moderate levels when drinking, and maintaining regular physical activity with at least 30 minutes of daily exercise to promote overall health.
Generally, doctors recommend colorectal cancer screening for individuals aged 50 and above. Since early-stage colorectal cancer often presents no noticeable symptoms, screening enables asymptomatic individuals to assess their risk level and detect potential disease early for prompt treatment.
Common Diagnostic Methods
When symptoms suggestive of colorectal cancer are present, prompt medical consultation and diagnostic evaluation are recommended. Physicians typically employ the following approaches to assess for colorectal cancer.
This initial examination assesses for possible colorectal cancer. The physician performs a digital rectal examination by inserting a gloved finger into the rectum to palpate for abnormal masses or swelling.
This endoscopic examination enables direct inspection of the colonic mucosa for pathological findings. Preparation requires a low-residue diet several days prior, followed by bowel cleansing through laxative administration and oral hydration. The procedure involves trans anal insertion of a colonoscope, with optional biopsy sampling for histopathological evaluation when indicated.
This diagnostic procedure involves fluoroscopic imaging of the colon. Pre-procedure bowel cleansing may include rectal irrigation. Under fluoroscopy, a barium contrast medium is instilled into the rectum to opacify the colonic lumen, facilitating detailed radiographic evaluation.
In addition to the examinations above, doctors will conduct further tests to determine whether the tumour has spread to other organs such as the lungs or liver.
A blood test is conducted to assess hepatic function. Elevated liver enzymes may suggest metastatic involvement of the liver.
To assess for pulmonary metastasis of cancer cells.
The technology employs X-ray imaging to reconstruct detailed 3D representations of internal structures, offering substantially greater diagnostic data than standard planar radiographs, thereby enhancing clinical evaluation.
The physician guides a handheld transducer across the abdominal area; computer software processes the ultrasonic waves to generate real-time visualisations of the liver and abdominal structures.
The modality employs magnetic resonance to reconstruct axial body images to examine internal anatomical structures.
Based on these examinations, doctors will stage the patient’s condition. Colorectal cancer is typically classified into the following 4 stages:
Primary Treatment Approaches
The three principal modalities for colorectal cancer management are surgical resection, systemic chemotherapy, and radiotherapy. Localised disease may be treated with surgery alone, while locally advanced cases often require multimodal therapy (surgery with adjuvant chemo/radiation). Metastatic disease is primarily managed with palliative chemotherapy.
Tumour characteristics, including morphology and dimensions, determine surgical planning. Standard treatment involves oncologic resection of the colorectum with en bloc lymphadenectomy and primary anastomosis. When primary reconstruction is not feasible, creating a diverting stoma with external faecal collection may be required. For metastatic disease to pulmonary or hepatic sites, the following interventions may be indicated:
A needle-shaped electrode is inserted into the hepatic tumour site, delivering electrical current to generate localised hyperthermia for tumour cell destruction.
This modality similarly achieves tumour eradication through thermal energy, utilising microwave radiation instead of electrical current.
A cryoprobe is introduced into the tumour mass, inducing cytotoxic effects via controlled tissue hypothermia.
Early postoperative ambulation is strongly encouraged to enhance recovery. Temporary urinary catheterisation or surgical drain placement may be required during the initial days. Oral intake is restricted until return of bowel function (typically 2-3 days postop), progressing from clear liquids to bland diet by postoperative days 4-5.
Most patients regain normal sexual function following colorectal resection. However, male patients undergoing rectal excision may experience neurogenic erectile or ejaculatory dysfunction due to pelvic nerve plexus injury, though such complications are uncommon and often transient.
This treatment targets the characteristic of cancer cells that they divide more rapidly than normal cells. It uses drugs to kill these cells. The drugs are typically administered through a vein in the arm or via a catheter inserted into the chest, where they dissolve into the bloodstream and travel throughout the body, seeking out and destroying cancer cells along the way. Each treatment cycle is usually spaced two to three weeks apart, with the number of cycles depending on the condition and the patient’s response to the drugs.
Some patients who have undergone surgical removal of a tumour may find that cancer cells have already spread to nearby lymph nodes, or doctors may assess that the risk of recurrence is high. In such cases, chemotherapy is used as “Adjuvant Chemotherapy” to reduce the risk of recurrence.
After treatment, patients may experience various side effects, such as fatigue, hair loss, nausea, and diarrhoea. In addition, certain chemotherapy drugs, like Fluorouracil, may cause redness, swelling, and pain in the palms and soles of the feet, although these effects generally do not last long.
Patients also have the option of receiving targeted therapy. Targeted drugs are another type of anti-cancer medication that can be used in combination with chemotherapy to enhance the effectiveness of treatment or extend the patient’s lifespan. Although the side effects of targeted drugs are relatively mild, they can still impact the body, depending on the type of drug: EGFR inhibitors [Note 2] can cause fever, muscle pain, and even difficulty breathing and shock after the initial injection; angiogenesis inhibitors [Note 3] can lead to high blood pressure, proteinuria, and even blood clots.
This treatment uses high-energy rays to destroy cancer cells. It can focus on irradiating the tumour while avoiding damage to normal cells. Since it is a localised treatment, areas not reached by the rays remain unaffected. Before undergoing radiation therapy, doctors will mark the patient’s skin to ensure that the rays accurately target the intended area within the body.
In the case of colorectal cancer, radiation therapy is more frequently used for rectal cancer and less so for colon cancer. If doctors determine that surgical removal is challenging or if scans reveal that the tumour is in an advanced stage, radiation therapy may be administered before surgery. After surgery, some patients who are at higher risk of recurrence may also need radiation therapy. Additionally, if the patient’s health permits, radiation therapy can be combined with chemotherapy to enhance the treatment effect. However, this combination also increases the side effects.
After receiving radiation therapy, patients may experience various side effects, including nausea, diarrhoea, fatigue, and skin sensitivity. Moreover, suppose the radiation therapy involves a large area of the bone marrow. In that case, it may reduce the number of white blood cells, platelets, and red blood cells, making patients more susceptible to infections, bleeding, or anaemia. Patients should get plenty of rest and avoid injuries or dizziness.
In terms of sexual function, if radiation therapy is administered in the pelvic area, women’s ovaries may lose function, leading to permanent menopause and symptoms such as hot flashes, sweating, and vaginal dryness; men’s testicles may also lose the ability to produce sperm, resulting in infertility. Radiation therapy can also cause inflammation of the bladder lining, or lead to redness, swelling, and pain in the skin of the genital and perineal areas, and even ulcers, causing painful urination and affecting sexual activity.
The severity of side effects depends on the radiation dose and the treatment course length. Most discomfort can be alleviated with medication.
Personal Care
Following treatment, patients should consult their physicians to develop a personalised follow-up care plan, including scheduled monitoring to detect potential recurrence or metachronous tumours. This enables timely intervention while managing treatment-related complications to optimise recovery. Dietary modifications are essential, particularly avoiding hard-to-digest, high-fat foods and other irritants that may exacerbate gastrointestinal symptoms.
Further Understanding
Cancer Foundation: Understanding Cancer: Colorectal CancerNotes:
1. Contrast agents are administered intravenously and circulate through the bloodstream to target organs. They attenuate X-ray beams, enhancing tissue visibility during imaging.
2. EGFR inhibitors, a class of targeted therapies, work by blocking growth-signalling pathways in cancer cells, ultimately inducing apoptosis.
3. Angiogenesis inhibitors, another category of targeted drugs, suppress tumour vascularisation to starve cancer cells of nutrients and oxygen.
*Sources:
Cancer Online Resource Hub
▣ The information on this website has been reviewed by the HEAL Medical Team and is regularly updated according to the most recent clinical evidence. All content is provided for general informational purposes only and should not replace professional medical advice. Please consult your doctor or another qualified healthcare professional for personalized medical guidance.
Our centre operates from Monday to Friday, 09:00 AM to 5:30 PM, and Saturday, 09:00 AM to 1:00 PM. For appointments or to speak with our staff, please call +852 3598 9090.
Should you need to contact us outside business hours, kindly leave a message, and we’ll get back to you as soon as possible.