Cancer Antigen CA27.29 question

I am looking for information for my mother.  She was dx with breast cancer 6 years ago.  After chemo, and 5 yrs of Tamoxifen, she was cancer free.  About 9 months ago, a test report came back showing that her CA27.29 was slightly elevated above normal (I think it was in the 40's).  No sign of cancer could be detected, however, after she underwent a bone, liver, and CT scan.  She has been retested twice since then and her CA level continues to increase.  It is currently about 140.  Again, her scans have been negative.  Her oncologist wants to put her on a new medication similar to Tamoxifen.  She would rather not put up with the side effects and argues that no sign of cancer has been found yet.  Could you please tell me specifically (or refer me to an article) which benign diseases and/or conditions could possibly affect the CA27.29 test?  I have been unable to find detailed information on this test.  I am also looking for journal articles on its efficacy.  Also, why is this test used only to detect reoccurance and not for screening rather than mamography?  Any information would be helpful.  Thank you in advance.

[CCF-RN,MSN-JS]

Dear Kate, The use of CA27.29 to detect breast cancer recurrence at present is controversial.
When other alternative causes of elevated CA 27.29 have been eliminated, an abnormal test result may indicate recurrent disease.  However, there has been no evidence to date that treatment based solely on CA27.29 elevation significantly improves overall survival rates.  The American Society of Clinical Oncologists (last update in 1997) guidelines state that at present the data are insufficient to recommend routine use of CA27.29 for screening, diagnosis, staging or surveillance following primary treatment.  Although an increasing CA 27.29 can detect recurrence following primary treatment, the clinical benefit is not established.  When discussing clinical benefit they are talking about will this have an effect on disease free or overall survival? Will the benefit of early treatment outweigh the risks of treatment side effects?  The answers or evidence in regards to these questions is not currently available.

Elevated levels may be found in-patients with other diseases such as ovarian cysts, uterine fibroids, intestinal or colonic problems, medication; Paxil, hepatitis, tuberculosis, systemic lupus.

Whether your mother should proceed with treatment based solely on the elevated CA27.29 would have to be seriously weighed based on risks of treatment and unknown overall benefit.  An opinion from another oncologist may help you in making your decision.

[bernieM]

A related discussion, what is meaning of elevated ca27-29 was started.