Many of us wish there was an easy way to detect cancer early enough. What about cancer markers, you ask?
As its name suggests, cancer markers can indicate the presence of cancer in a person. However, they are not as widely used for cancer diagnosis as you might think, because most cancer markers are not specific enough. The high number of false positives from cancer marker tests makes them not ideal for diagnosis at the moment. Conversely, patients with cancer can have normal levels of cancer markers too.
But why may your doctor still recommend taking a cancer marker test? What are they useful for? Here are some answers to your questions about cancer markers.
What are cancer markers?
Cancer markers, sometimes also called tumour markers, are substances present in the body due to cancer. They could be a compound associated with the tumour cells itself, or a chemical produced by the body in response to cancer. In other cases, these may be certain mutations in particular cells, or an abnormal level of a compound that’s normally already present in the body.
There are different markers for different cancers, but not all markers are specific to just one cancer. For example, the test for alpha fetoprotein can be indicative of liver cancer or some types of testicular cancer. Another marker, CA 19-9, could be used to study the presence of pancreatic cancer, pancreatitis, colon cancer, stomach cancer, or bile duct cancers.
As you might have noticed, cancer markers do not just indicate the presence of cancer. Some may be associated with other non-cancerous health conditions as well. For example, CA 125 is a cancer marker for ovarian cancer, but it can be raised in patients who has fluid accumulation in the abdominal space. And that is the reason why cancer markers are not usually conclusive as cancer diagnostic tests.
Why screen for cancer markers?
Testing for cancer markers can be highly useful in a variety of scenarios, not limited to diagnosis.
In suspected cases of cancer, doctors may recommend a test for cancer markers as part of the diagnosis process. While cancer markers alone are not conclusive of cancer, their detection can be useful at giving information about the nature of the patient’s condition. Most doctors will follow-up a positive cancer marker test with more conclusive tests like an MRI, CT scan, or biopsy.
Recently diagnosed cancer patients may also be recommended a cancer marker test to give information about the nature of the cancer – for example, the extent of its spread, how aggressive it is, and so on. This will aid the cancer specialist in coming up with suitable treatment programmes for the patient.
Cancer marker tests may be performed regularly on patients undergoing cancer treatment. This helps the doctor monitor the progress of treatment, and how well the disease is reacting to treatment. Stubbornly high or rising cancer marker levels can be clues that the treatment is not effective, or that the cancer is turning more aggressive.
For some cancers, cancer markers can be used to detect the recurrence of cancer. That is why these tests are also performed routinely on patients after successful treatment.
How do doctors check for cancer markers?
Most commonly, cancer markers are tested for through blood tests. Once the doctor has obtained the sample, they will send it to the laboratory for testing.
Various methods of testing are used to detect and measure the level of the cancer marker, depending on the specific marker in question.
For cancer marker measurements taken to monitor treatment progress, the test is repeated at intervals before, during, and after the treatment programme. This offers a more detailed view of how the marker levels change over time.
Doctors have detected raised cancer markers. What should I do?
Raised cancer markers may indicate many things: cancer, recurring cancer, or certain other medical issues.
Before you panic, consult your doctor about what other tests they can recommend to you. Raised cancer markers are not a firm diagnosis. You should accompany it with other tests such as a comprehensive physical examination, CT, MRI or PET scans, and biopsies to have a better indication.
If you are taking cancer marker tests as part of monitoring for ongoing cancer treatment, raised cancer markers are often signify that the treatment is not effective. You might require a stronger treatment or different type of treatment altogether. Speak to your cancer specialist about what changes they can recommend.
While cancer markers today are not yet a definitive diagnostic tool for cancer, they are still useful in a myriad of other ways in the diagnosis, treatment, and monitoring of cancer. Meanwhile, cancer researchers are working hard to explore how these biomarkers can help to diagnose early cancers and predict treatment effectiveness. Hopefully, we will be able to see more efficient and reliable cancer screening methods in the near future!