Early detection is key when it comes to cancer prevention and treatment. One of the tools available for this purpose is the cancer marker test, which helps in detecting certain proteins or substances in the blood that may indicate the presence of cancer. But when should you consider getting tested? This article explores the best timing for a cancer marker test, who should take it, and how it can support early diagnosis and monitoring.

Understanding Cancer Marker Tests

A cancer marker test measures specific substances, called tumor markers, that may be produced by cancer cells or by the body in response to cancer. These markers vary depending on the type of cancer and can be found in blood, urine, or tissues. Some of the commonly known cancer markers include PSA (for prostate cancer), CA-125 (for ovarian cancer), and CEA (for colorectal and other cancers).

While cancer marker tests are useful, they are not definitive diagnostic tools. They are often used alongside other tests, such as imaging and biopsies, to confirm a diagnosis or monitor treatment progress. It is important to understand that cancer markers can also be elevated due to non-cancerous conditions such as infections or inflammation, making professional medical interpretation essential.

When to Consider a Cancer Marker Test

It is important to undertake cancer screening that is appropriate, evidence based and recommended by guidelines. For the average risk person without symptoms, the following cancer screening is recommended: 

Colorectal Cancer 

For those age 50 and above, 

• Faecal occult blood testing once a year OR 
• Colonoscopy once every 10 years OR 
• CT colonography once every 5 years 

Cervical Cancer 

From age 25-29: Pap smear every 3 years 

From age 30 and above: HPV DNA test every 5 years 

Breast Cancer

From age 40-49: Mammography screening once a year 

From age 50-69: Mammography screening once every 2 years 

1. If You Have a Family History of Cancer

Individuals with a strong family history of cancer, particularly hereditary cancers such as breast, ovarian, or colorectal cancer, should consider undergoing a cancer marker test as part of their regular health screenings. 

Early detection in high-risk individuals can lead to more effective preventive measures and early intervention. Genetic predisposition plays a significant role in cancer development, and identifying risks early can improve outcomes.

2. If You Have Persistent or Unexplained Symptoms

Unexplained symptoms such as prolonged fatigue, unexplained weight loss, persistent pain, or unusual lumps should not be ignored. While these symptoms may be caused by benign conditions, they could also be warning signs of underlying malignancies. A cancer marker test may help in identifying the need for further investigations.

Other concerning symptoms include changes in bowel habits, chronic indigestion, difficulty swallowing, and unusual bleeding. If you experience any of these symptoms over an extended period, it is advisable to seek medical consultation and discuss whether a cancer marker test is necessary.

4. If You Are Undergoing Cancer Treatment

For individuals already diagnosed with cancer, cancer marker tests are often used to track the effectiveness of treatment. A decreasing level of cancer markers may indicate a positive response to therapy, while increasing levels may signal disease progression or recurrence. 

These tests provide doctors with critical information on whether to continue, adjust, or change the treatment plan.

Furthermore, specific treatments such as chemotherapy, immunotherapy, and targeted therapies can affect cancer marker levels differently. Physicians use these fluctuations to assess treatment impact and make timely medical decisions.

5. After Cancer Treatment for Monitoring Recurrence

Even after successful cancer treatment, there is always a risk of recurrence. Regular cancer marker tests can help detect any resurgence of cancer, allowing for early intervention before the disease becomes more advanced. Surveillance testing is particularly crucial for cancers known to have high recurrence rates, such as ovarian or colorectal cancer.

Survivors often undergo regular check-ups where cancer marker tests are part of post-treatment care plans. Combining these tests with imaging scans, physical exams, and lifestyle modifications can significantly enhance long-term survival and quality of life.

Limitations of Cancer Marker Tests

While cancer marker tests can provide valuable insights, they have limitations. Elevated markers do not always mean cancer is present, as they can sometimes be caused by benign conditions, infections, or inflammatory diseases. Conversely, not all cancers produce detectable markers, which means a normal test result does not guarantee the absence of cancer.

Additionally, different laboratories may have varying reference ranges for marker levels, which is why results should always be interpreted by experienced healthcare professionals. Over-reliance on these tests without considering clinical findings can lead to unnecessary anxiety or misdiagnosis.

False positives and false negatives also pose challenges. A false positive result may lead to unnecessary further testing and emotional distress, while a false negative could provide false reassurance and delay appropriate care. Hence, marker tests should be used in conjunction with other diagnostic modalities.

The Importance of Consultation with a Doctor

Deciding whether or not to take a cancer marker test should always be done in consultation with a healthcare professional. A doctor can evaluate individual risk factors, symptoms, and medical history to determine whether testing is necessary. Additionally, they can interpret test results accurately and recommend appropriate follow-up actions.

It is also crucial to understand the role of screening versus diagnostic testing. While routine cancer marker screening is beneficial for high-risk individuals, testing without symptoms or risk factors may lead to unnecessary concerns. A thorough discussion with a doctor helps ensure that the test is medically justified and beneficial.

Other Diagnostic Methods Complementing Cancer Marker Tests

Given the limitations of cancer marker tests, additional diagnostic methods are often used to confirm or rule out cancer. Some common complementary methods include:

• Imaging Tests: X-rays, MRIs, CT scans, and PET scans provide detailed visualizations of abnormal growths or tumors.
• Biopsies: Tissue sampling is one of the most definitive methods for diagnosing cancer and understanding tumor characteristics.
• Genetic Testing: Identifying genetic mutations can help assess hereditary cancer risk and guide personalized treatment options.

Using a combination of these methods ensures more accurate diagnosis and helps in making well-informed treatment decisions.

Conclusion

A cancer marker test is a valuable tool in the early detection and monitoring of cancer, especially for those with risk factors or existing health concerns. However, it is not a standalone diagnostic method and should be used alongside other screening methods. 

If you have a family history of cancer, persistent symptoms, or lifestyle risks, consulting a doctor about cancer marker testing could be a proactive step toward maintaining good health. Regular check-ups and timely screenings can significantly improve the chances of early detection and successful treatment.

Understanding when and why to take a cancer marker test is essential for effective preventive healthcare. While these tests offer important insights, they work best when combined with other diagnostic tools and medical evaluations. 

If you are uncertain about your cancer risk, seeking medical advice and undergoing appropriate screenings can contribute to early detection, timely intervention, and better health outcomes.

Reference/s:

https://www.nccs.com.sg/patient-care/cancer-types/pages/cancer-screening.aspx