Understanding Lab Values - Tumor Markers

In addition to typical blood work that may be done such as a Complete Blood Count (CBC) and Comprehensive Metabolic Panel (CMP), your provider may order a tumor marker test. A tumor marker is a substance found in your blood, urine, or body tissue. Blood tests are the most common way to test for tumor markers.   The following are a few facts about tumor markers: 

  • High tumor marker levels can be a sign of certain types of cancer 

  • Tumor markers can assist in diagnosing cancer and or monitoring your response to treatment.  

  • While tumor marker results can assist oncologists in better understanding your disease, it is important to remember that fluctuation of tumor marker levels is normal. A single change in tumor marker numbers does not necessarily indicate a change in your cancer. The overall trend of the tumor marker numbers over time is more important than a single value.    

  • There are different tumor markers for different types of cancers. 

  • Not all cancers make cells with tumor markers, therefore tumor marker testing is not always performed.   

  • Tumor markers are made at higher levels by cancer cells than by normal cells.  Elevated tumor markers can be associated with benign conditions. For example, the CA-125 blood test is very useful for patients with certain ovarian malignancies but can also be elevated in benign conditions like endometriosis.  

Depending on your diagnosis, the following are some tumor markers you could see in your lab results before, during and after treatment: 

Cancer Type 

Possible Tumor Marker Tests 

Stage When Measured 

Prostate Cancer 

 Prostate Specific Antigen (PSA) 

All stages 

Breast Cancer 

Cancer Antigen 15-3 (CA 15-3) 

CA 27-29   

Carcinoembryonic Antigen (CEA) 

Stage IV  

Colorectal Cancers 

CEA 

Stages II, III, IV 

Testicular Cancer 

Human Chorionic Gonadotropin (HCG) 

Alpha-fetoprotein (AFP)  

Lactate Dehydrogenase (LDH)  

All stages 

Hepatocellular Carcinoma (HCC), or Liver Cancer 

AFP 

All stages 

Ovarian Cancer 

Cancer Antigen 125 (CA 125) 

All stages 

Pancreatic Cancer 

Carbohydrate antigen 19-9 (CA 19-9) 

All stages 

Additional points to keep in mind regarding tumor markers are the limitations of these tests. A variety of conditions, such as common viruses and inflammation, may cause elevated tumor marker levels. Tumor marker levels alone are not definite indicators of disease but only assist in providing information about the cancer. Other tests, such as body scans, are needed to diagnose cancer and monitor disease progression or recurrence.  

Questions to ask your doctor: 

  • Is there a tumor marker for my type of cancer? 

  • What does my tumor marker mean? 

  • How often will you order this test to be performed? 

  • What results are we looking for during treatment?  

 

Tests and procedures. Cancer.Net. (n.d.). Retrieved December 30, 2021, from https://www.cancer.net/navigating-cancer-care/diagnosing-cancer/tests-and-procedures/tumor-marker-tests 

 

Tumor markers in common use. National Cancer Institute. (n.d.). Retrieved December 30, 2021, from https://www.cancer.gov/about-cancer/diagnosis-staging/diagnosis/tumor-markers-list 

 

U.S. National Library of Medicine. (2021, September 14). Tumor marker tests: Medlineplus medical test. MedlinePlus. Retrieved December 30, 2021, from https://medlineplus.gov/lab-tests/tumor-marker-tests/ 

 

Types of Tumor Markers. Stanford Health Care (SHC) - Stanford Medical Center. (2017, September 12). Retrieved December 30, 2021, from https://stanfordhealthcare.org/medical-tests/t/tumor-markers/types.html 

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