Ovarian cancer occurs when abnormal cells in the ovary begin to grow in an uncontrolled way. In response to this process, the body will produce tumor markers.

By testing for tumor markers, doctors can confirm the presence of cancer and gauge its severity. Carcinoembryonic antigen (CEA) is a tumor marker that can be present in people with ovarian cancer. However, it is not particularly useful for detecting this form of cancer, as other tumor marker tests are more reliable.

This article explains what CEA tests are and what they can tell doctors about ovarian cancer. It also discusses what to expect from a CEA test, the risks of this procedure, and some other tumor marker tests.

A scientist testing for CEA levels.Share on Pinterest
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As the National Cancer Institute (NCI) explains, tumor markers are simply substances, usually proteins, that bear a specific relationship to cancer cells. Certain cells either contain or produce tumor markers. These cells could be cancer cells themselves or cells that the body produces in response to cancer.

Tumor markers tend to exist at elevated levels in the body of someone with cancer. By testing for tumor marker levels, doctors can gain evidence that someone has cancer. Tumor marker tests may also help doctors stage the cancer, assess the efficacy of any treatment, and estimate the person’s outlook.

However, this evidence is somewhat unreliable as people can have elevated tumor marker levels without having cancer.

CEA is a nonspecific tumor marker, and elevated levels can happen in people with various forms of cancer, including:

Ovarian cancer is a serious condition in which the cells of the ovaries mutate, leading to uncontrolled and abnormal growth. If a person does not receive treatment, this cancer can spread to other body parts.

This cancer accounts for about 1.2% of all cancer cases, and the 5-year relative survival rate is about 48.6%.

A 2020 study suggests that CEA levels are elevated in people with cancerous mucinous ovarian tumors. Mucinous ovarian tumors begin in specific ovary cells, which exist in the outermost parts of the ovaries. CEA levels are also elevated in people with borderline mucinous ovarian tumors. These tumors exist at the limit between benign and cancerous tumors.

The study authors conclude that testing for CEA levels can help doctors discern whether a mucinous ovarian tumor is benign, borderline, or cancerous. However, this may not apply to other ovarian tumor subtypes.

Doctors typically test CEA levels by collecting a small sample of blood and sending it to a laboratory for testing.

The first step involves the person sitting down and getting comfortable. The individual should inform the healthcare professional of any relevant fears, such as those involving blood or needles, in case they have a tendency to feel faint. This can help the healthcare professional prepare for this scenario.

The healthcare professional will choose a suitable vein for taking blood, which will usually be one in the arm or hand. They will wrap a tourniquet around that arm, which makes the vein more prominent.

Using a needle and syringe, the doctor or nurse will puncture the vein to draw blood. They will then remove the tourniquet and use gauze or cotton wool to apply pressure to the vein. This will reduce bleeding. The whole procedure takes less than 5 minutes and does not require the person to fast beforehand.

Although taking blood samples is a safe procedure, some unwanted effects are possible. The risks associated with CEA blood tests include:

  • pain
  • stinging
  • bleeding
  • bruising

The risk of infection is possible but uncommon. Some people might also feel faint or dizzy due to a phobia of blood or needles.

A doctor will interpret the results of the test.

Research has linked blood CEA levels greater than 3.8 units per milliliter (ml) with an increased risk of the ovarian tumor being borderline or cancerous. CEA levels above this level do not necessarily mean that the tumor is cancerous. However, they indicate that further testing will likely be beneficial.

In people already receiving treatment for cancer, a reduction in CEA levels may mean that the treatment is working, while consistently high levels may mean that the cancer is not responding to treatment.

CEA tests are not the only tumor marker test for ovarian cancer. Elevated levels of CA125 and CA19 tumor markers also suggest a cancerous mucinous ovarian tumor.

As the American Cancer Society (ACS) explains, CA125 tests are helpful for detecting ovarian cancers more broadly. The ACS also notes that some tumor marker tests can help detect germ cell ovarian cancers, which begin in cells that have the capacity to turn into egg cells. These tumor markers include:

  • human chorionic gonadotropin (hCG)
  • alpha-fetoprotein (AFP)
  • lactate dehydrogenase (LDH)

By checking for elevated CEA levels, doctors can get a more accurate impression of whether someone’s ovarian tumor is benign.

However, as with tumor marker tests in general, these results are prone to generating false positives and false negatives. For this reason, doctors will not rely solely on CEA tests for diagnosing ovarian cancer.