Colorectal cancer is a type of cancer that begins in the colon or rectum, often developing from abnormal growths called polyps.
Imagine noticing a persistent change in your bowel habits or spotting blood in your stool. At first, you might brush it off as something minor — stress, diet or assume it is just a fleeting issue. However, such symptoms could be early warning signs of colorectal cancer, a condition that often begins silently but has significant implications if left unaddressed. In fact, the most common stage for colorectal cancer presentation is advanced stages (III and IV), with a significant portion of patients presenting with stage IV disease. (For explanation regarding the various stages, please see the table below)
Colorectal cancer develops in the colon or rectum, often starting as small, non-cancerous growths called polyps. While many polyps remain harmless, some can slowly turn into cancer. As such, this progression highlights the importance of awareness, early detection, and timely intervention.
Understanding colorectal cancer is not just about managing the disease; it is about empowering yourself with the knowledge to prevent it or catch it in its earliest stages when treatment is most effective. Whether through regular screenings, healthy lifestyle choices or recognising subtle symptoms, proactive steps can make all the difference.
In this guide, we will delve into the key aspects of colorectal cancer, from its causes, and risk factors to diagnosis, treatment, and prevention strategies. By understanding the disease and its nuances, you take the first step toward safeguarding your health, and that of your loved ones.
What is Colorectal Cancer?
Colorectal cancer is one of the most treatable cancers. However, as symptoms are only noticeable in advanced stages, many patients receive late diagnosis, which impacts the treatment outcome.
Colorectal cancer refers to cancers that begin in the colon or rectum, which are integral parts of the digestive system. These cancers typically develop over time from polyps. Polyps starts as small non-cancerous growths in the inner lining of the colon or rectum. If these polyps are left untreated, some can transform into malignant tumours. Thus, making early detection immensely crucial.
Colorectal cancer is a significant health concern in Singapore, where it remains as the most commonly diagnosed cancers for men and women combined, particularly among adults over 50. According to the Singapore Cancer Registry [1], it accounts for about 17% of all cancer cases in men and 13% in women. With these statistics underscoring its prevalence, public awareness and timely intervention are vital.
Understanding Colorectal Cancer
Polyps develop in the inner linings of the colon or rectum, which are parts of the digestive tract.
To fully understand colorectal cancer, it is essential to grasp the anatomy of the colon, and rectum, which form the final part of the digestive system. The colon absorbs water, and nutrients from digested food, while the rectum stores waste before elimination. Together, they play a critical role in digestive health.
Colorectal cancer begins when cells in the colon or rectum grow uncontrollably. This process typically starts with benign polyps that may develop into cancer over years due to genetic changes. Adenocarcinomas are the most common type of colorectal cancer, accounting for over 95% of cases [2]. Meanwhile, less common forms include carcinoid tumours, and gastrointestinal stromal tumours.
Genetics, and cell mutations also play a pivotal role. Hereditary conditions like Lynch syndrome, and familial adenomatous polyposis significantly increase the risk of colorectal cancer. These conditions cause mutations in specific genes that regulate cell growth, and repair. However, most cases of colorectal cancer are sporadic, meaning they result from acquired mutations rather than inherited ones. As a result, this complexity further highlights the importance of understanding individual risk factors.
What are the risk factors for Colorectal Cancer?
Both obesity, and sedentary lifestyle have been associated with increasing the risk of developing colorectal cancer.
Colorectal cancer is influenced by various risk factors, ranging from lifestyle choices to genetic predispositions, and environmental influences. While some risks can be modified through lifestyle changes, others, like age, and genetics, require vigilant monitoring, and proactive measures. Understanding these risks is crucial for prevention, and early intervention.
Lifestyle-Related Risks
Diet – a diet high in red or processed meats [3], and low in fibre increases the likelihood of colorectal cancer. Such foods may produce harmful compounds during digestion, while fibre aids in healthy bowel movements, and reduces toxin exposure in the colon.
Physical Inactivity – sedentary lifestyles are linked to slower digestion, and increased cancer risk [4]. Engaging in regular exercise has been linked to lowering the risk of cancer as it boosts metabolic health, and helps maintain a healthy weight.
Obesity – excess body fat, particularly around the abdomen, is associated with higher levels of insulin, and inflammatory markers, which can promote cancer cell growth [5].
Smoking – tobacco contains carcinogenic chemicals that can damage the lining of the colon, and rectum. In fact, long-term smokers have a significantly higher risk [6] of colorectal cancer.
Alcohol Consumption – excessive alcohol intake is associated with increased cancer risk due to its effect on liver function [7], and DNA repair processes.
Genetic and Hereditary Factors
Family History – individuals with close relatives who have had colorectal cancer are at a higher risk, especially if the relative was diagnosed before age 50 [8].
Hereditary Syndromes – conditions like Lynch syndrome [9], and familial adenomatous polyposis [10] are caused by inherited genetic mutations that significantly raise cancer risk. In such cases, early screening, and preventive surgeries are often recommended for affected individuals.
Environmental and Other Factors
Age – the risk of colorectal cancer increases with age, particularly after 50 [11], due to cumulative cell damage over time.
Ethnicity – some ethnic groups, such as individuals of East Asian descent [12], may have unique genetic or dietary factors contributing to higher susceptibility.
Occupational Hazards – long-term exposure to chemicals or toxins, such as in manufacturing industries, can elevate cancer risk [13].
What are the symptoms of Colorectal Cancer?
Changes in bowel movements, and bloody stools are one of the early signs of colorectal cancer.
Recognising the symptoms of colorectal cancer is critical for timely diagnosis, and treatment. While early-stage symptoms are often subtle, and easily dismissed, advanced stages produce more noticeable signs.
As such, by understanding these symptoms, it will help empower individuals to seek medical attention before the disease progresses.
Likely Initial Symptoms
Changes in Bowel Habits – persistent diarrhoea, constipation, or changes in stool consistency may indicate abnormal colon activity.
Blood in the Stool – this may appear as bright red streaks or darker, tar-like stools, signalling bleeding in the colon or rectum.
Unexplained Fatigue – blood loss, even in small amounts, can cause anaemia, leading to chronic fatigue, and weakness.
Advanced-Stage Symptoms
Persistent Abdominal Pain – cramping or discomfort in the lower abdomen can result from tumour growth obstructing the digestive process.
Unintended Weight Loss – a sudden, unexplained drop in weight could indicate cancer interfering with nutrient absorption or increased metabolic activity.
Bowel Obstruction Symptoms – severe constipation, bloating, or nausea may occur if a tumour blocks the colon.
When to Seek Medical Attention
It is crucial not to dismiss these symptoms as minor issues, particularly if they persist for a few weeks or more. Early medical evaluation can lead to early detection, which significantly improves treatment outcomes. As a matter of fact, colorectal cancer is one of the most preventable, and treatable cancers provided the polyps are detected early – before it becomes malignant.
How is Colorectal Cancer diagnosed?
A colonoscopy is regarded as the gold standard in diagnosing colorectal cancer as it helps doctors to examine the colon, and rectum closely, and to take tissue samples if a growth is found.
One of the reasons early detection is crucial is because colorectal cancer often begins without noticeable symptoms. By identifying the disease at an early stage, it improves survival rates [14], and prevents progression. In contrast, delaying seeking medical attention raises several risks, including:
Risks of Colorectal Cancer Detection Delays
Missed Early-Stage Detection – early-stage colorectal cancer may present with no symptoms, causing individuals to delay screening. Without early detection, the cancer can progress to more advanced stages, reducing the chances of successful treatment.
Overlooking Subtle Symptoms – common but mild symptoms like changes in bowel habits or minor rectal bleeding may be dismissed as unrelated conditions, thereby delaying diagnosis. However, recognising these as potential warning signs is critical for timely intervention.
Avoidance of Screening Due to Fear or Discomfort – many avoid screening procedures like colonoscopy due to fear or perceived discomfort, which increases the risk of undetected polyps developing into cancer.
Screening and Diagnostic Methods
Diagnosing colorectal cancer accurately, and early is key to effective treatment, and improved survival rates. Screening not only detects cancer but can also identify precancerous polyps, which can be removed before they develop into cancer. Some of the available diagnostic methods include:
Colonoscopy – considered the gold standard, a colonoscopy allows doctors to visually examine the colon, and rectum for abnormalities. During the procedure, polyps can be removed for further testing. And a biopsy can be done for any bigger growth or suspected cancer.
Stool-Based Tests – tests like the Faecal Immunochemical Test (FIT) detect hidden blood in stool samples. These are minimally invasive, and widely available, with free FIT kits offered to eligible individuals in Singapore. However, they may miss smaller polyps or lesions.
Imaging Tests – advanced imaging methods, such as CT colonography, provide detailed visuals of the colon. Although Colonoscopy is the gold-standard method for undertaking colon and rectal assessment, a CT colonography (non-invasive technique) may be used when colonoscopy is unsuitable to be done for certain individuals.
Biopsy – when abnormalities are detected, a biopsy may be performed. This involves removing a small tissue sample for microscopic analysis, which confirms the presence of cancer, and its type.
What are the stages of Colorectal Cancer?
Colorectal cancer is categorised into five stages as it helps doctors to plan the treatment route.
Colorectal cancer staging is based on the TNM system, which assesses tumour size (T), lymph node involvement (N), and metastasis (M). These factors determine how far the cancer has spread.
Stages range from 0 to IV:
Stage 0
At this stage, the cancer is confined to the innermost layer of the colon or rectum. Treatment typically involves surgical removal of abnormal cells or polyps, which is often curative. Additionally, the 5-year survival rate for Stage 0 is nearly 100% [15].
Stage I
In this stage, the cancer has grown into the inner layers of the colon or rectum but has not spread beyond the wall. Surgery is often recommended to remove the tumour, and is often curative. However, the 5-year survival rate for Stage I is approximately 90% [16].
Stage II
Stage II cancer has grown through the wall of the colon or rectum, and may have spread to nearby tissues but not to the lymph nodes. Surgery is the primary treatment, sometimes followed by chemotherapy. While the 5-year survival rate ranges from 70% to 85% [17], curability is possible with effective treatment, particularly for Stage IIA.
Stage III
At this stage, the cancer has spread to nearby lymph nodes but not to distant organs. Treatment involves a combination of surgery, chemotherapy, and sometimes radiation therapy. The 5-year survival rate is approximately 50% to 70% [18], depending on the extent of lymph node involvement. While curability becomes more challenging, aggressive treatment can lead to long-term remission for some patients.
Stage IV
Stage IV cancer has metastasized to distant organs such as the liver, lungs, or other sites. Treatment often focuses on palliative care, though surgical resection of metastases combined with chemotherapy or targeted therapies can occasionally lead to long-term survival. The 5-year survival rate is about 10% to 15% [19], and curability is rare. However, advancements in treatment continue to improve outcomes for select cases, with an increase in the 5 yr survival rates to up to 30%..
What are the treatment options for Colorectal Cancer?
Chemotherapy is one of the treatment options for colorectal cancer. In some cases, doctors will combine chemotherapy with other treatment options, such as surgeries, to achieve optimal results.
Treating colorectal cancer requires a personalised approach based on the cancer’s stage, location, and the patient’s overall health. This section introduces treatment methods, outlines their associated risks, and highlights symptoms managed during the process.
Surgical Treatments
Surgery is often the first line of defence, with options include:
Polypectomy – removal of polyps during a colonoscopy. However, this procedure is only effective for early-stage cancers.
Colectomy – partial or full removal of the colon, sometimes paired with lymph node dissection.
Minimally Invasive Surgeries – techniques like laparoscopic surgery or robotic surgery may offer reduced recovery time, and lower complication rates.
Chemotherapy and Radiation
Chemotherapy – chemotherapy uses drugs to kill cancer cells or prevent them from multiplying. It is often combined with other treatments to maximise effectiveness.
Radiation Therapy – radiation therapy targets, and shrinks tumours before surgery or manages symptoms in advanced cases. Due to its potential side effects, patients are closely monitored to ensure these side effects are managed effectively.
Targeted, and Immunotherapies
Targeted Therapy – targeted therapy includes drugs like monoclonal antibodies block specific proteins that fuel cancer growth.
Immunotherapy – immunotherapy activates the body’s immune system to attack cancer cells, offering hope for advanced or resistant cases.
Holistic and Supportive Therapies
These address the physical, and emotional challenges of treatment.
Nutrition – a balanced diet helps manage treatment side effects, and supports recovery.
Physiotherapy – improves mobility, and strength after surgery or prolonged treatment.
Psychological Support – counselling services assist in managing stress, and emotional health.
Living With Colorectal Cancer
It is important to incorporate physical activities or exercises into your routine as a means to lower your risk of developing colorectal cancer. However, patients who have undergone or are undergoing treatment should speak with your doctors.
A colorectal cancer diagnosis marks a significant life challenge, impacting physical health, emotional well-being, and daily life. However, with proper care, a supportive network, and practical strategies, individuals can navigate this journey and improve their quality of life.
Coping with the Diagnosis
The emotional impact of a cancer diagnosis can be overwhelming. Feelings of fear, anxiety, and sadness are common, and natural responses. With that in mind, seeking professional help from counsellors or psychologists can provide valuable coping mechanisms, such as mindfulness techniques, and cognitive behavioural therapy (CBT).
Meanwhile, support groups offer another vital resource. Speaking with others who share similar experiences can foster a sense of belonging, and reduce feelings of isolation. In Singapore, organisations like the Singapore Cancer Society provide counselling services, peer support, and workshops for both patients, and families.
Lifestyle Adjustments During Treatment
Treatment for colorectal cancer often requires significant changes in daily routines to manage side effects, and maintain strength:
Dietary Modifications – a balanced diet rich in nutrients can support recovery, and overall health. Foods that are high in fibre, such as fruits, vegetables, and whole grains, help regulate digestion. On the other hand, avoiding processed foods, spicy dishes, and alcohol can also minimise discomfort.
Physical Activity – light to moderate exercise, such as walking or yoga, helps reduce fatigue, improve mood, and strengthen the body. However, activities should be tailored to individual abilities, and approved by doctors.
Managing Side Effects – side effects like nausea, fatigue, or bowel irregularities are common during treatment. It is important to remember that open, and honest communication you’re your doctor can help identify effective medications or therapies to alleviate discomfort.
Support Systems and Survivorship
A robust support system is essential during and after treatment. Family, friends, and caregivers provide emotional reassurance, and practical help with daily tasks. In Singapore, resources like cancer support groups, and survivorship programmes [20] encourage individuals to share experiences and advice.
Survivorship begins when active treatment ends, and life gradually returns to normal. Regular follow-ups, a healthy lifestyle, and stress management play critical roles in preventing recurrence, and improving long-term well-being. Many survivors find renewed purpose in life, engaging in advocacy or education to support others facing similar challenges.
How can I prevent Colorectal Cancer?
Colorectal cancer is a highly preventable disease. By adopting healthier lifestyle choices combined with regular check-ups, you will be taking proactive measures to safeguard your health.
Preventing colorectal cancer requires proactive measures to reduce risk factors, and promote early detection. By adopting a healthy lifestyle, staying vigilant about screening, and considering preventive options, individuals can significantly lower their chances of developing this disease.
Regular Screening and Early Detection
Screening is the most effective way to detect, and prevent colorectal cancer. This is because early detection allows for the identification, and removal of polyps before they become cancerous.
Age Guidelines – in Singapore, individuals aged 50 years old, and older are encouraged to undergo regular screenings. However, those with a family history of colorectal cancer or hereditary conditions may need to start earlier as they have a higher risk of developing the disease. It is important to also note that over the last decade, there has been a steady increase in earlier onset of colorectal cancer in people in younger ages of between 30-50 years.
Methods – colonoscopy remains the gold standard, providing a comprehensive view of the colon and enabling the removal of polyps during the procedure. The FIT is widely available, and offered for free in certain Singaporean programmes. However, because FIT has limitations, regular follow-ups are vital.
Lifestyle Modifications
Lifestyle choices have a profound impact on colorectal cancer risk. Here are some key modifications to adopt:
Healthy Diet – a diet rich in fibre, fruits, vegetables, and whole grains can lower the risk of colorectal cancer. Additionally, avoiding red, and processed meats, as well as excessive fat, and sugar, is equally important. By replacing these with plant-based proteins, and lean meats, it helps to promote digestive health.
Exercise – regular physical activity, such as walking, cycling, or swimming, helps maintain a healthy weight, and reduces inflammation, both of which lower cancer risk. The World Health Organization (WHO) recommends at least 150 minutes of moderate activity [21] per week.
Avoidance of Carcinogens – smoking, and excessive alcohol consumption are significant risk factors for colorectal cancer. Quitting smoking and limiting alcohol intake can drastically reduce the likelihood of developing cancer.
Role of Preventive Medications and Supplements
There is no conclusive evidence that medications/supplements can prevent the development of colorectal cancer. However, there are some studies and evidence that certain medications, and supplements may lead to reducing colorectal cancer risk, particularly in high-risk individuals:
Aspirin – few studies suggest that low-dose aspirin can lower the risk [22] of developing colorectal cancer by reducing inflammation. However, it is crucial to consult a doctor before starting aspirin therapy, as it may have side effects.
Calcium [23] and Vitamin D – these nutrients may play a role in maintaining colon health. Including calcium-rich foods, like dairy products and leafy greens, and getting adequate sunlight for vitamin D [24] can provide added protection. On the other hand, supplements may be recommended for those with deficiencies.
Conclusion
Early detection is crucial in preventing colorectal cancer, and safeguarding your colon health.
It goes without saying that colorectal cancer is a significant health concern. However, with early detection, effective treatments, and lifestyle modifications, the prognosis can be improved – especially with early detection. In fact, understanding the risk factors, symptoms, and screening methods empowers individuals to take proactive steps towards prevention, and early diagnosis. This, combined with advances in medical technology, such as minimally invasive surgeries, continues to enhance treatment outcomes, and the patients’ quality of life.
Remember, regular screenings, and a healthy lifestyle are key factors in reducing the risk of colorectal cancer. By staying informed, and proactive, you can protect your health, and that of your loved ones.
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