Bowel Cancer

What is Bowel Cancer?

Bowel cancer, also known as colorectal cancer, is a type of cancer that affects the colon or rectum, which are parts of the digestive system. It typically starts as small growths called polyps on the inner lining of these organs. While not all polyps become cancerous, some can progress into colorectal cancer.

Impact of Bowel Cancer On Anatomy and Health

Bowel cancer typically starts in the inner lining of the colon or rectum. As it progresses, it can invade deeper layers of the bowel wall. Symptoms can vary but may include changes in bowel habits (diarrhoea or constipation), blood in the stool, abdominal pain, and unexplained weight loss. As the cancer grows, it can obstruct the bowel, causing bowel movements to become difficult or painful. If left untreated, bowel cancer can spread to nearby lymph nodes and other organs, making it more challenging to treat and potentially life-threatening.

Causes and Risk Factors for Bowel Cancer

Several factors can increase the risk of developing bowel cancer:

• Age: Bowel cancer is more common in older individuals, with most cases diagnosed in people over 50.
• Family History: If you have a family history of bowel cancer or certain genetic conditions, such as Lynch syndrome or familial adenomatous polyposis (FAP), your risk is higher.
• Personal History: If you've had colorectal polyps or previous cases of bowel cancer, your risk of developing it again is increased.
• Lifestyle Factors: Unhealthy lifestyle choices such as a high-fat diet, lack of physical activity, smoking, and excessive alcohol consumption can contribute to a higher risk.
• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can increase the risk of bowel cancer over time.
• Race and Ethnicity: Certain racial and ethnic groups, such as African Americans and Ashkenazi Jews, risk developing colorectal cancer.
• Obesity: Being overweight or obese is associated with an increased risk of bowel cancer.

Symptoms of Bowel Cancer

The symptoms of bowel cancer can vary, and some people may experience no symptoms in the early stages. It's crucial to be aware of the following potential signs:

• Changes in Bowel Habits: Persistent changes in bowel habits can be a warning sign. This includes diarrhoea, constipation, or a feeling that the bowel doesn't empty.
• Blood in the Stool: Blood in the stool, either as visible red blood or as dark, tarry stools, can indicate colorectal cancer.
• Abdominal Discomfort: Ongoing abdominal pain, cramps, or discomfort, especially if it's associated with changes in bowel habits, should be evaluated.
• Unexplained Weight Loss: Significant and unexplained weight loss, without changes in diet or activity, can be a symptom of various health issues, including bowel cancer.
• Fatigue: Unexplained and persistent fatigue can sometimes be a symptom of advanced bowel cancer.
• Iron Deficiency Anaemia: This can occur if the cancer causes bleeding in the gastrointestinal tract, leading to low iron levels.
• Nausea or Vomiting: In some cases, bowel cancer can lead to nausea and vomiting.
• Bowel Obstruction: As the cancer grows, it may block the bowel, causing symptoms like severe abdominal pain, bloating, and an inability to pass gas or stools.

Types of Bowel Cancer

• Adenocarcinoma is the most common type of bowel cancer, accounting for over 95% of cases. Adenocarcinoma starts in the cells that line the inside of the colon or rectum. It often begins as a polyp, which can become cancerous over time.
• Carcinoid Tumours: These are rare and usually grow in the lining of the gastrointestinal tract. While they are typically slow-growing and less aggressive than adenocarcinomas, they can still become cancerous and require treatment.
• Gastrointestinal Stromal Tumours (GISTs): These tumours are rare in the colon and rectum but can occur. They develop in the connective tissue of the digestive tract and are usually treated differently than adenocarcinomas.
• Lymphoma: Colorectal lymphomas are uncommon and originate in the lymphatic system within the colon or rectum. They require specialised treatment.
• Sarcomas: Sarcomas are rare and can occur in the soft tissues of the colon or rectum. They are usually treated with a combination of surgery and other therapies.

Stages of Bowel Cancer

The stages of bowel cancer describe the extent to which the cancer has spread and help determine the appropriate treatment. Bowel cancer is typically staged from 0 to IV, with higher stages indicating more advanced disease:

• Stage 0 (Carcinoma in situ): Cancer cells are found only in the innermost lining of the colon or rectum and have not invaded deeper layers. Treatment often involves surgical removal of the tumour.
• Stage I: Cancer has invaded the submucosa (the layer beneath the inner lining) but has not spread to nearby lymph nodes or distant organs. Surgery is the primary treatment.
• Stage II: This stage is divided into two subcategories:
• Stage IIA: Cancer has invaded the muscularis propria (muscle layer) but has not spread to nearby lymph nodes or distant organs.
• Stage IIB: Cancer has invaded the serosa (outermost layer) but has not spread to nearby lymph nodes or distant organs. Surgery is the primary treatment for both subcategories.
• Stage III: Cancer has spread to nearby lymph nodes but has not reached distant organs. Treatment typically involves surgery, chemotherapy, and sometimes radiation therapy.
• Stage IV: At this advanced stage, cancer has spread to distant organs, such as the liver, lungs, or distant lymph nodes. Treatment may include surgery, chemotherapy, targeted therapy, immunotherapy, and palliative care to manage symptoms and improve quality of life.

Diagnosis of Bowel Cancer

• Medical History and Physical Examination: Your doctor will begin by taking a detailed medical history and conducting a physical examination. They will ask about your symptoms and risk factors.
• Screening Tests: If you have no symptoms but are at risk due to age or family history, your doctor may recommend screening tests such as a colonoscopy, sigmoidoscopy, or faecal occult blood test (FOBT) to detect early signs of bowel cancer.
• Diagnostic Tests: If you have symptoms or if screening tests suggest a potential issue, your doctor may order diagnostic tests, including:
• Colonoscopy: A procedure in which a flexible tube with a camera is inserted into the colon to visualise the lining and take tissue samples (biopsies).
• CT Scan: A computed tomography (CT) scan may be performed to assess the extent of the cancer and check for spread to nearby lymph nodes or organs.
• MRI: Magnetic resonance imaging (MRI) can provide detailed images of the colon and rectum.
• Blood Tests: Blood tests can help evaluate your overall health and check for markers associated with colorectal cancer.

Treatment of Bowel Cancer

Common treatment options include:

• Surgery: Surgical removal of the tumour and nearby lymph nodes is a standard treatment for early-stage bowel cancer. Different surgical approaches, such as colectomy or rectal resection, may be used depending on the tumour's location.
• Chemotherapy involves using medications to kill cancer cells or stop their growth. It is often used with surgery, especially in more advanced stages of bowel cancer.
• Radiation Therapy: Radiation therapy uses high-energy beams to target and destroy cancer cells. It may be used before or after surgery or in combination with chemotherapy for rectal cancer.
• Targeted Therapy: Targeted therapies target specific cancer growth and spread molecules. They are sometimes used in combination with chemotherapy.
• Immunotherapy: Immunotherapy drugs help the immune system recognise and attack cancer cells. While not a standard treatment for all bowel cancers, it may be an option in certain cases.
• Palliative Care: In advanced stages or when the cancer is not curable, palliative care focuses on managing symptoms and improving the quality of life.

What if Bowel Cancer is Untreated?

Untreated bowel cancer can lead to serious health consequences, including:

• Advanced Cancer: Without treatment, bowel cancer can progress to advanced stages, making it more challenging to treat and potentially spreading to other organs.
• Worsening Symptoms: Symptoms such as abdominal pain, bowel obstruction, bleeding, and weight loss may worsen, causing significant discomfort and reducing quality of life.
• Complications: Untreated bowel cancer can lead to complications like perforation (a hole in the bowel), severe infections, and anaemia due to ongoing bleeding.
• Reduced Survival: Early detection and treatment offer the best chance for a favourable outcome. Untreated bowel cancer is associated with a lower chance of survival.

Regular screenings, awareness of symptoms, and timely medical consultation are crucial for improving the prognosis and quality of life for individuals diagnosed with this condition. Discussing bowel cancer with a healthcare professional is highly recommended if you have concerns about it or its treatment.