Tumour Markers for Colorectal Cancer
Colorectal cancer, a disease affecting the colon or rectum, is a significant health concern. It's the second most commonly diagnosed cancer among both men (16.2% of all cancers) and women (12.9%) in Singapore.
While early stages may be mistaken for less serious conditions, there's a way to check for cancer in your bowels — bowel cancer tumour markers.
Tumour markers are substances produced by cancer cells or the body in response to cancer. In colorectal cancer, these markers can be valuable tools. Doctors use them to monitor the progression of the disease, assess the effectiveness of treatment, and detect potential recurrence.
What are The Limits to Using Tumour Markers to Diagnose Colon Cancer?
While tumour markers can be helpful, they're not foolproof for diagnosing colorectal cancer. Normal levels of a tumour marker for colon cancer don't guarantee the absence of cancer, and elevated levels can sometimes occur in other conditions.
Here are some limitations to keep in mind:
- Not specific to cancer: Elevated levels of some tumour markers can be associated with non-cancerous conditions like inflammation or infection.
- Not always elevated in early stages: Tumour markers may not be significantly elevated in the early stages of colorectal cancer, making early detection challenging.
- Individual variation: Tumour marker levels can vary significantly between individuals, making it difficult to establish a universal threshold for diagnosis.
It's important to remember that cancer markers for colon cancer are just one piece of the puzzle. Doctors always use them with other diagnostic tests, such as colonoscopies and biopsies, along with a thorough clinical evaluation.
Types of Cancer Tumour Markers for Colorectal Cancer
There are several types of tumour markers that can be used in the management of colorectal cancer. Some are found in the blood, while others are detected by analysing the tumour tissue itself.
Tumour Markers Found in the Blood
The primary tumour marker for colon cancer found in the blood is a carcinoembryonic antigen (CEA). Although not specific to bowel cancer, it is often elevated in individuals with this disease. CEA levels are typically measured before surgery to help predict prognosis, during treatment to monitor response, and after treatment to detect recurrence.
Other potential blood markers for colorectal cancer include:
- CA 19-9: This marker is associated with various cancers, including colorectal cancer. Elevated levels may suggest a poorer prognosis or advanced disease.
- Tissue inhibitor of metalloproteinases-1 (TIMP-1): This marker may be elevated in individuals with colorectal cancer and could be useful in monitoring treatment response.
Tumour Markers Found in Tumour Tissue
In addition to blood tests, doctors can analyse the tumour tissue itself for specific genetic mutations or changes. These tumour markers for colorectal cancer can provide valuable information about the tumour's characteristics and help guide treatment decisions.
Key tumour markers found in colorectal tissue include:
- Carcinoembryonic Antigen (CEA): While also found in the blood, CEA levels in the tumour tissue itself can provide additional prognostic information. Higher levels of CEA in the tumour may indicate a more aggressive cancer with a higher risk of recurrence.
- Microsatellite Instability (MSI): This marker indicates a high degree of genetic instability within the tumour and may predict a better response to certain treatments, particularly immunotherapy. MSI is caused by defects in the DNA mismatch repair system, which normally corrects errors that occur during DNA replication.
- KRAS, NRAS and BRAF Mutations: These mutations can affect the tumour's response to targeted therapies, helping doctors select the most effective treatment options. For example, if a tumour has a KRAS mutation, certain targeted therapies, like EGFR inhibitors, may not be as effective.
- Mismatch Repair (MMR) Proteins: Deficiencies in these proteins can lead to MSI and may indicate a higher risk of cancer recurrence. MMR proteins are responsible for correcting errors in DNA replication. When these proteins are deficient, errors accumulate, leading to genetic instability and an increased risk of cancer.
- Ki-67: This marker measures the proportion of actively dividing cells in the tumour and can help predict prognosis. A higher Ki-67 index indicates a faster-growing tumour, which may be associated with a poorer prognosis.
- EpCAM: This protein is often overexpressed in colorectal cancer cells and may be a target for future therapies. Researchers are exploring ways to use EpCAM to deliver drugs or other therapies directly to cancer cells, potentially increasing treatment effectiveness and reducing side effects.
This type of analysis allows medical professionals to advise a suitable course of action, based on individual tumour marker profiles, to manage colorectal cancer. It allows doctors to tailor treatment plans to each patient's specific tumour profile, improving the effectiveness of treatment.
Tests to Diagnose and Stage Colorectal Cancer
If your doctor suspects colorectal cancer, they will recommend various tests to confirm the diagnosis and determine the stage of the cancer. This staging process is important to understand the extent of the cancer's spread and guide treatment decisions.
1. Colonoscopy
A colonoscopy is a procedure where a long, flexible tube with a camera attached is inserted into the rectum to examine the entire colon. This allows the doctor to visualise the lining of the colon, identify any abnormalities like polyps or tumours, and take tissue samples (biopsies) for further analysis.
Colonoscopy is considered the gold standard for colorectal cancer screening and diagnosis.
2. Biopsy
During a colonoscopy or other diagnostic procedures, if any suspicious areas are found, a biopsy is performed.
A biopsy is typically performed during a colonoscopy or other diagnostic procedures when suspicious areas, such as polyps or tumours, are detected. These areas might look different in colour or texture compared to the surrounding healthy tissue. Sometimes, a biopsy might be recommended even if no visible abnormalities are found, especially if there's a strong family history of colorectal cancer or other risk factors.
The biopsy itself involves removing a small tissue sample from the suspicious area. This sample is then sent to a laboratory where a pathologist examines it under a microscope. The pathologist looks for the presence of cancer cells and assesses their characteristics, such as the grade of the tumour (how abnormal the cells look) and whether they are invasive (spreading into surrounding tissues).
In addition to examining the cells under a microscope, the tissue sample may also undergo molecular testing. Molecular tests analyse the genes, proteins, and other molecules within the cancer cells. This can provide valuable information about:
- The specific type of colorectal cancer: Different types of colorectal cancer have different genetic profiles, which can influence prognosis and treatment decisions.
- The likelihood of the cancer spreading: Some molecular markers can predict the risk of metastasis (spread) to other parts of the body.
- The potential effectiveness of certain treatments: Molecular tests can help identify which targeted therapies might be most effective for a particular individual's cancer.
3. Imaging Tests
Imaging tests provide detailed pictures of the inside of your body, helping doctors assess the extent of the cancer and whether it has spread to other organs.
Several types of imaging tests may be used:
- Computed Tomography (CT or CAT) Scan: Uses X-rays to create detailed cross-sectional images of the body. CT scans can help determine the size and location of the tumour and whether it has spread to nearby lymph nodes or distant organs.
- Ultrasound: Uses high-frequency sound waves to create images of the body's internal organs. In colorectal cancer, ultrasound may be used to examine the liver for signs of cancer spread.
- Magnetic Resonance Imaging (MRI) Scan: Uses strong magnetic fields and radio waves to produce detailed images of the body. MRI scans can provide more detailed images of the tumour and surrounding tissues than CT scans.
- Positron Emission Tomography (PET) Scan: Uses a small amount of radioactive material to create images of the body's metabolic activity. PET scans can help identify areas of active cancer cells, including those that may have spread to other parts of the body.
- Angiography: An X-ray procedure that uses a special dye to visualise blood vessels. In colorectal cancer, angiography may be used to assess the blood supply to the tumour before surgery.
Protect Yourself Well Before a Cancer Diagnosis
Early detection of colorectal cancer, combined with comprehensive treatment strategies, significantly improves the chances of successful outcomes. However, cancer can strike anytime, and treatments can be costly. Building a strong financial foundation and being covered for critical illnesses like cancer can provide peace of mind during challenging times.
For Singaporeans looking for financial protection against the medical expenses following a cancer diagnosis, Income Insurance offers Complete Cancer Care, a term life insurance plan designed to help alleviate financial worries during cancer treatment, enabling individuals to prioritise their health and well-being without the added burden of financial strain.
Here are some key features of this plan:
- Future premiums waived1 for a specified period up to the end of the policy term upon the diagnosis of major cancer.
- Receive up to 1% of the sum assured per month for up to 24 months2 to help reduce the out-of-pocket expenses for cancer treatment.
- Receive 10% of the sum assured3 for hospice and palliative care.
Dealing with unforeseen illnesses, such as cancer, can be highly stressful, both physically and emotionally. Learn more about Complete Cancer Care and prepare your finances for unexpected outcomes so you can focus on recovery with greater peace of mind.
1 Income will pay the Premium Waiver Benefit according to your selected option under the Major Cancer Benefit.
- If the policyholder selected Care 50, upon diagnosis of early or intermediate stage major cancer, Income will waive the premiums up to 60 months or end of policy term, whichever is earlier, and the policyholder will have to pay premiums thereafter. This benefit for early or intermediate stage major cancer can only be claimed once. Income will waive the premiums until the end of policy term upon diagnosis of advanced stage major cancer.
- If the policyholder selected Care 100, Income will waive the premiums until the end of policy term upon diagnosis of any stage of major cancer.
The premium waiver will start from the policy month immediately after the diagnosis date of the major cancer. The policy will continue to apply for the remaining unclaimed benefits during this premium waiver period even though the policyholder is not paying the premiums. Income will not pay this benefit if the insured suffered symptoms of, had investigations for, or was diagnosed with, any stage of major cancer any time before or within 90 days from the cover start date.
2 Income will pay a Monthly Cancer Therapy Benefit as long as the insured is diagnosed with major cancer by a specialist and recommended in writing that the treatment is a necessary medical treatment for cancer according to relevant guidelines from Ministry of Health (MOH) and has started cancer treatment as advised by a specialist. Income will make the first payment starting from the policy month immediately after the cancer treatment start date. For more details on the types of cancer treatment, please refer to the policy conditions. The maximum amount Income will pay for this benefit is $60,000 per life. Income will not pay more than a total number of 12 payouts for early or intermediate stage major cancer. If the insured has already received payouts during early stage, there will not be further payouts during intermediate stage. The sum of the total number of payouts for this benefit will not exceed 24 payouts. The number of payouts for the advanced stage major cancer will be 24 less the number of payouts Income have paid for the early or intermediate stage major cancer under this benefit. Income will not pay this benefit if the insured suffered symptoms of, had investigations for, or was diagnosed with, any stage of major cancer any time before or within 90 days from the cover start date. Please refer to the policy conditions for further details.
3 Income will pay 10% of the sum assured if the insured is successfully admitted to an inpatient palliative care facility or engaged the home palliative or day palliative care services from providers listed by Singapore Hospice Council (SHC) during the policy term. The insured must be diagnosed with terminal cancer by a specialist and a referral for palliative care services made by a specialist is required. Providers listed by SHC, which may be updated from time to time, can be found at singaporehospice.org.sg/services. The benefit will terminate after this benefit is claimed in full. Income will not pay this benefit if the insured suffered symptoms of, had investigations for, or was diagnosed with, any stage of major cancer any time before or within 90 days from the cover start date.
This article is meant purely for informational purposes and does not constitute an offer, recommendation, solicitation or advise to buy or sell any product(s). It should not be relied upon as financial advice. The precise terms, conditions and exclusions of any Income Insurance products mentioned are specified in their respective policy contracts. Please seek independent financial advice before making any decision.
These policies are protected under the Policy Owners’ Protection Scheme which is administered by the Singapore Deposit Insurance Corporation (SDIC). Coverage for your policy is automatic and no further action is required from you. For more information on the types of benefits that are covered under the scheme as well as the limits of coverage, where applicable, please contact Income Insurance or visit the GIA/LIA or SDIC websites (www.gia.org.sg or www.lia.org.sg or www.sdic.org.sg).
This advertisement has not been reviewed by the Monetary Authority of Singapore.
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