Colorectal Cancer: Causes, Symptoms and Treatment Options

Colorectal cancer is one of the most common types of cancer, which originates in the colon or rectum. In many cases, it begins with small growths known as polyps that are usually harmless at first, but can turn cancerous. The challenge is that the disease often progresses quietly, showing no signs in its early stages. Symptoms such as blood in the stool, persistent changes in bowel habits, or unexplained weight loss usually appear later, when treatment can become more complex. This is why understanding the risk factors and recognising early warning signs are so important. In this blog, we take a closer look at what causes colorectal cancer, the symptoms that should not be ignored, and the treatment options that the doctor may suggest post diagnosis. But before we get into all that, let us go through the basics of colorectal cancer.

What is Colorectal Cancer?

Colorectal cancer refers to malignancies that begin in the colon or rectum and advance through distinct stages, from growth limited to the intestinal wall to disease that spreads to distant organs. Its development is influenced by genetic susceptibility, pre-existing medical conditions, and lifestyle-related risks. In many cases, symptoms emerge only in the later stages, which can delay diagnosis. Treatment choices are guided by the stage of the disease and may include surgery, chemotherapy, radiation therapy, or targeted therapies. Prognosis is closely linked to how early the cancer is detected: outcomes are generally favourable in the initial stages but become significantly less positive once the disease progresses beyond the intestine.

What Causes Colorectal Cancer?

The exact cause of colorectal cancer is not always clear, but research shows that it develops through a combination of genetic changes, medical conditions, and lifestyle-related factors. These influences can alter the normal growth cycle of cells in the colon or rectum, eventually leading to cancer. The risk factors include:

• Genetic Factors: A family history of colorectal cancer or inherited syndromes, such as Lynch syndrome and familial adenomatous polyposis (FAP), can significantly increase the risk. In these cases, mutations passed down through generations make cells more likely to develop abnormal changes that progress to cancer.
• Age and Gender: The risk of colorectal cancer rises steadily with age, especially after 50 years, although younger cases are being reported more frequently. It also tends to occur slightly more often in men than in women.
• Lifestyle-Related Risks: Dietary habits play a strong role. Regular consumption of red or processed meats, coupled with low fibre intake, may increase risk, whereas diets rich in fruits, vegetables, and whole grains are protective. Physical inactivity, obesity, smoking, and heavy alcohol consumption are also associated with a higher chance of developing the disease.
• Medical Conditions: Certain health conditions can contribute to colorectal cancer risk. People with long-standing inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease, have a higher likelihood of developing malignancies in the colon or rectum. Type 2 diabetes has also been linked to increased risk.
• Genetic Mutations Acquired Over Time: Even in people without a family history, genetic changes can accumulate in colon or rectal cells during a lifetime. These mutations may result from environmental exposures, lifestyle factors, or random errors in cell division, eventually disrupting normal cell regulation and allowing cancer to develop.

What are the Symptoms of Colorectal Cancer?

Colorectal cancer often develops quietly, with no symptoms in the early stages. As the tumour grows, noticeable signs may appear, which can differ depending on where the cancer is located in the colon or rectum. Common symptoms include:

• Changes in bowel habits: Persistent diarrhoea or constipation, a sudden shift in stool frequency, or a feeling that the bowel does not empty completely. Stools may also become narrower or ribbon-like if the tumour partly blocks the intestine.
• Blood in the stool: Bright red streaks, maroon-coloured stool, or stool that looks dark and tarry may indicate bleeding. In some cases, bleeding is not visible but leads to low blood counts.
• Abdominal discomfort: Cramping, bloating, or a sensation of fullness can result from a growing tumour. In advanced cases, obstruction may cause severe pain and vomiting.
• Unexplained weight loss: A steady reduction in body weight without changes in eating habits or exercise may occur as the cancer alters metabolism or interferes with nutrient absorption.
• Persistent fatigue and weakness: Ongoing tiredness may be due to anaemia from chronic blood loss in the intestine. This can also cause dizziness, pale skin, and reduced physical stamina.
• Other general symptoms: Loss of appetite, nausea, or a general decline in energy levels may appear in later stages.

How is Colorectal Cancer Diagnosed?

Colorectal cancer diagnosis involves several steps that help detect the disease, confirm its presence, and determine how advanced it is. Doctors usually begin with an assessment of risk factors and symptoms, followed by specialised tests to identify and study the tumour.

Medical History and Physical Examination

The first step often includes a review of personal and family history. A history of colorectal cancer, polyps, or inherited conditions such as Lynch syndrome can increase risk. Doctors also ask about symptoms such as changes in bowel habits, bleeding, or unexplained weight loss. A physical examination may include a digital rectal exam, where the doctor checks the rectum for growths or abnormalities.

Screening Tests

Screening is essential because colorectal cancer can develop silently for years.

• Colonoscopy: The most reliable method, where a thin tube with a camera is inserted into the rectum to examine the colon. Polyps or suspicious tissue can be removed immediately.
• Sigmoidoscopy: Similar to colonoscopy, but examines only the lower part of the colon and rectum.
• Stool-based tests: These include the faecal occult blood test (FOBT), faecal immunochemical test (FIT), and stool DNA test. They detect hidden blood or genetic changes, serving as non-invasive tools that can signal the need for further testing.

Imaging Studies

Imaging helps confirm the presence of cancer and determine its spread.

• CT scan: Provides detailed cross-sectional images of the abdomen and pelvis to look for tumours or metastasis.
• MRI: Often used to assess rectal cancers, offering precise images of local invasion and involvement of nearby tissues.
• CT colonography (virtual colonoscopy): Uses CT imaging to recreate a view of the colon and rectum, helpful for patients unable to undergo traditional colonoscopy.
• PET scan: Sometimes used to detect cancer spread to distant organs.

Laboratory Tests

Laboratory investigations support diagnosis and guide management.

• Stool tests: Identify hidden blood or genetic mutations linked with colorectal cancer.
• Blood tests: Include a complete blood count to detect anaemia from chronic bleeding. Tumour markers like carcinoembryonic antigen (CEA) may also be checked. Though not diagnostic on their own, they help monitor response to treatment and detect recurrence.

Biopsy and Pathology

A biopsy is required for a definitive diagnosis. During colonoscopy or surgery, small samples of tissue are removed and examined under a microscope. Pathologists assess the type of cancer, its aggressiveness (grade), and may also perform molecular testing to detect genetic alterations that can influence treatment choices.

What are the Treatment Options for Colorectal Cancer?

Treatment for colorectal cancer depends on the stage of the disease, the location of the tumour, and the overall health of the patient. In most cases, a combination of therapies is used to achieve the best possible outcome.

• Surgery: Surgical removal of the tumour is often the first line of treatment, especially in early-stage cancers. The type of surgery may range from removing a small section of the colon or rectum (local excision) to more extensive procedures such as colectomy, where part of the colon is removed along with nearby lymph nodes. In some advanced cases, surgery may also involve creating a temporary or permanent stoma.
• Chemotherapy:Chemotherapy uses drugs to destroy cancer cells and is commonly used when the cancer has spread beyond the intestine or to reduce the risk of recurrence after surgery. It may be given orally or intravenously and is usually administered in cycles.
• Radiation Therapy:Radiation therapy involves using high-energy rays to target and kill cancer cells. It is more often used in rectal cancer, either before surgery to shrink tumours or after surgery to reduce the chance of recurrence.
• Targeted Therapy: Targeted drugs focus on specific changes in cancer cells that allow them to grow and spread. Unlike traditional chemotherapy, these medicines aim to interfere with cancer growth more precisely, sometimes with fewer side effects.
• Immunotherapy: In certain cases, especially for patients with specific genetic changes such as microsatellite instability-high (MSI-H) tumours, immunotherapy can be an option. These treatments help the body’s immune system identify and attack cancer cells.
• Palliative Care: For advanced cases where a cure is not possible, palliative treatments help relieve symptoms, improve comfort, and maintain quality of life. This may include managing pain, bowel problems, or other cancer-related complications.

Consult Today

Colorectal cancer is a serious condition that can progress silently, making early detection essential. Max Hospital offers comprehensive colorectal cancer care, from accurate diagnosis to advanced treatment options and follow-up support. If you notice any warning signs or are at increased risk, consult Max Hospital promptly to receive thorough guidance and effective care.

Frequently Asked Questions

What increases my risk of developing colorectal cancer besides age and family history?

Certain lifestyle factors, including a diet high in processed or red meat, low fibre intake, smoking, heavy alcohol use, and physical inactivity, can increase risk. Chronic medical conditions such as type 2 diabetes or inflammatory bowel disease also play a role.

Can colorectal cancer be prevented entirely?

While it may not be fully preventable, risk can be significantly reduced through regular screening, a balanced high-fibre diet, maintaining a healthy weight, regular exercise, and avoiding tobacco and excessive alcohol. Removal of precancerous polyps during colonoscopy is another effective preventive step.

How often should I get screened for colorectal cancer?

Screening recommendations vary depending on age and risk factors. Generally, adults are advised to start regular screening at age 45. People with higher risk, such as a family history of colorectal cancer or inherited syndromes, may need to begin earlier and have more frequent tests.

Are there hereditary forms of colorectal cancer I should be aware of?

Yes, conditions like Lynch syndrome and familial adenomatous polyposis (FAP) are inherited genetic syndromes that significantly increase colorectal cancer risk. Genetic counselling and testing can help identify these conditions and guide preventive strategies.

Does colorectal cancer always cause symptoms?

No, in many cases, especially early-stage cancer, there are no noticeable symptoms. This is why screening is critical, as it can detect cancer before it progresses or causes visible signs.

How does colorectal cancer affect daily life during treatment?

Treatment may involve surgery, chemotherapy, radiation, or targeted therapies. Side effects can include fatigue, changes in bowel habits, nausea, or temporary dietary restrictions. Support from healthcare providers, dietitians, and caregivers is essential to manage these effects.

Can diet and lifestyle changes help during or after treatment?

Yes, eating a balanced diet rich in fruits, vegetables, and whole grains, staying physically active, and maintaining a healthy weight can support recovery, improve energy levels, and reduce the risk of recurrence.

What follow-up care is necessary after treatment?

Regular follow-ups include physical exams, blood tests, imaging, and colonoscopies to monitor for recurrence or new polyps. The schedule and frequency depend on the stage of cancer and type of treatment received.

Is it possible to live a normal life after colorectal cancer treatment?

Many patients lead healthy, active lives post-treatment, especially if cancer is detected early. Ongoing follow-up care, lifestyle management, and monitoring are important to maintain long-term health.