Cancer Tumor Markers – Pros and Cons

Tumor markers are often used as a screen by GPs to rule out suspicions of cancer. You may even had a positive test yourself and are wondering about the implications of the result. There are many types of pathology marker tests, used for different tumor growths. The tumor test looks for either a substance in the body as a response to cancer cells, or substances produced by the cancer cells. Some common tumor markers are PSA (Prostate Specific Antigen) or the CA (Cancer antigen) groups (CA-15-3, CA 19-9, CA 125, CA27-29).

False Tumor Markers in Cancer

What Do The Tumor Markers Mean?

Some cancer markers are specific to one cancer such as the BTA (Bladder Tumor Antigen) urine test which is very specific to the urinary system, whereas other markers are seen in a group of cancers such as CA-15-3 which can be seen in breast cancer, lung cancer, ovarian cancer and gastrointestinal cancer.

These markers can be used to guide oncologist with treatment and progress of cancers however it is important to use them in combination with other tests to confirm diagnosis and also rule out other health issues which could be giving the positive tumor marker readings. There are several non-cancerous conditions that can cause tumor markers to be elevated and therefore these must be ruled out with further blood testing, biopsies or scans (eg PET, MRI, CT scan, ultrasound, etc).

Can Tumor Marker Tests Be Wrong?

Prostate Specific Antigen (PSA) was once considered a go-to screen for prostate cancer, although more recently it is understood to be not a clear cut effective test. PSA results can be high in benign prostatic hyperplasia (non-cancerous enlargement) or prostatitis. Some other tumor markers such as the HCG (Human Chorionic Gonadotrophin) used for testicular cancer, CEA (Carcinoembryonic Antigen) used for colorectal cancers or CA 125 used for ovarian cancer, can all be influenced by either diet, liver insufficiencies or medications.

Unfortunately tumor markers are not always elevated in all cases of the cancers they are used for and for this reason they can cause unnecessary stress and financial burden for patients. One example is the tumor marker CEA (carcinoembryonic antigen). It is used as a screen for  recurrence of bowel cancer, although according to current statistics it is only produced in 70-80% of colon cancer cases. This leaves around 20-30% of patients potentially missing the diagnosis of the return of their cancer.

Here are some of the most common tumor markers used in cancer screening and monitoring and the cause of potential false negatives.

Tumor Marker Test 

 Commonly Used For…

Reasons for False Positive Reading 

Carcinoembryonic Antigen
 Colorectal cancers, Breast, lung, gastric, pancreatic, bladder, kidney, thyroid, cervical, ovarian, liver, lymphoma, melanoma  Cigarette smoking, pancreatitis, hepatitis, inflammatory bowel disease (IBD), peptic ulcers, hypothyroidism, cirrhosis, COPD, biliary obstruction
CA 15-3 Cancer Antigen 15-3 Breast, lung, ovarian, endometrial, bladder, gastrointestinal Liver disease (cirrhosis, hepatitis), lupus, sarcoid, tuberculosis, non-cancerous breast lesions
CA 19-9 Cancer Antigen 19-9 Pancreas and colorectal, liver, stomach and liver cancers Pancreatitis, ulcerative colitis, IBD, inflammation or blockage of the bile duct, thyroid disease, rheumatic arthritis
CA 125 Cancer Antigen 125 Ovarian cancer, breast, colorectal, uterine, cervical, pancreas, liver cancer, lung Pregnancy, menstruation, endometriosis, ovarian cysts, fibroids, pelvic inflammatory disease, pancreatitis, cirrhosis, hepatitis, peritonitis, pleural effusion, surgery
CA 27.29 Cancer Antigen 27.29 Breast, Colon, gastric, liver, lung, pancreatic, ovarian, prostate cancers Ovarian cysts, liver and kidney disorders, non-cancerous (benign) breast problems
HCG Human Chorionic Gonadotrophin  Testicular cancers, gestational trophoblastic neoplasia  Pregnancy, marijuana use, hypogonadism, cirrhosis of the liver, IBD, duodenal ulcers
Prostate Specific Antigen
 Prostate Cancer  BPH (benign prostatic hypertrophy), nodular prostatic hyperplasia, prostatitis, prostate trauma, inflammation, recent ejaculation
 Thyroid Cancer  Autoimmune Anti-thyroglobulin antibodies
 NMP 22
(urine test)
 Bladder Cancer  BPH (benign prostatic hypertrophy), prostatitis




Does This Mean I Don’t Have Cancer?

Short answer, it’s unsure and you need to test more. Tumor markers can be very helpful in following response to any cancer treatment and to assess recurrence of cancer growth, but they cannot replace physical examinations, evaluation of presenting symptoms, and radiology studies such as PET scans or Xrays.

Have you got further questions or interested in natural cancer treatments to compliment your current treatment plan? Get in touch and ask a question.

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