Lay Summary: Tumor markers are occasionally useful but CEA is not well supported as an aid to monitoring or diagnosing breast cancer.
Tumor markers are measurable biochemicals that are associated with a malignancy. They are either produced by tumor cells (tumor-derived) or by the body in response to tumor cells (tumor-associated). They are typically substances that are released into the circulation and thus measured in the blood. There are a few exceptions to this, such as tissue-bound receptors that must be measured in a biopsy from the solid tumor or proteins that are secreted into the urine. Once cancer is diagnosed, tumor marker levels sometimes help to determine the extent of cancer. Higher levels can indicate more advanced cancer and a worse prognosis in some cases. The patient and their physician may use this information to choose between more or less aggressive treatments.
CEA is a glycoprotein most often associated with colorectal cancer, and used to monitor patients with this type of cancer. Its most popular use is in early detection of relapse in individuals already treated for colorectal cancer. After surgery, serial measurements indicate the surgery’s success and are used to detect early signs of recurrence. It has recently been found to be useful when measured during surgery for colorectal cancer to help determine prognosis and who will benefit from adjuvant treatment. We discuss the three most commonly used markers for breast cancer.
CEA is measured in the blood plasma. It is very non-specific and can be increased in many types of cancer: gastrointestinal, colorectal, ovarian, bladder, cervical, stomach, kidney, lung, pancreatic, liver, prostate, thyroid, melanoma, lymphoma, and breast. People with noncancerous conditions, such as cirrhosis or peptic disease, or inflammatory intestinal conditions such as colitis or diverticulitis, may also have increased levels. CEA levels can be elevated in elderly patients and in those who smoke.
CA 15-3 is produced by cells in the breast and increased levels can be associated with breast cancer. Rarely increased in women with early breast cancer, it may be used to detect recurrence of cancer in women following treatment or mastectomy and to monitor treatment for women with advanced breast cancer. However, adenocarcinomas of the ovary, lung, colon, and pancreas also express elevated CA 15-3 levels. Non-cancerous conditions sometimes associated with elevated CA 15-3 include benign breast or ovarian disease, endometriosis, pelvic inflammatory disease, and hepatitis. Pregnancy and lactation are also related to high CA 15-3 levels.
CA 27-29, also called breast carcinoma-associated antigen, is used as a marker for breast cancer. Eighty percent of women with breast cancer have an increased CA 27-29 level. This marker may be used with other procedures and tumor marker levels such as CA 15-3 to check for recurrences of cancer in previously treated women. Serial measurements monitor treatment response and identify recurrence.
Levels of CA 27-29 may also be increased in cancers of the colon, stomach, kidney, lung, ovary, pancreas, uterus, and liver. Noncancerous conditions associated with elevated CA 27-29 include first trimester pregnancy, endometriosis, ovarian cysts, non-cancerous breast disease, kidney disease, and liver disease.
Gudelines do not support use of CEA markers for diagnosis or monitoring of breast cancer. They do not recommend routine use of CEA in the surveillance of patients with diagnosed breast cancer. For monitoring patients with advanced disease, CEA should not be used alone. For monitoring patients with non-evaluable disease, CEA may occasionally be informative when CA 15-3/BR 27.29 is not. As a marker for breast cancer, CEA is generally less sensitive than CA 15-3/BR 27.29. Most experts consider Ca 15-3 and 27-29 to be of occasional value in breast cancer.
Dnistrian, Catharine M. Sturgeon, Rolf Lamerz, and James L. Wittliff .Practice Guidelines and Recommendations for Use of Tumor Markers in the Clinic ed. by Martin Fleisher, Ann M. AACC 2003
Lyndsay Harris, Herbert Fritsche, Robert Mennel, Larry Norton, Peter Ravdin, Sheila Taube, Mark R. Somerfield, Daniel F. Hayes, and Robert C. Bast Jr American Society of Clinical Oncology 2007 Update of Recommendations for the Use of Tumor Markers in Breast Cancer VOLUME 25 NUMBER 33 NOVEMBER 20 2007
Harris L, Fritsche H, Mennel R, et al. American Society of Clinical Oncology 2007 update of recommendations for the use of tumor markers in breast cancer. J Clin Oncol 2007; 25:5287.