CA27.29 value

I am 2.5 years out from a stage 1, invasive ductal carcinoma or breast cancer which was surgically removed, then radiation.  The cancer was less than 2 cm and all margins, including the lymph nodes were clear.  Chemo was not given due a 13 reading on the Oncotype DX test..

I was on Femara for almost 2 years with bad side effects.  Switched to tamoxifen for the last 6 months.  I also take zetia and lipitor for cholesterol as well as the usual vitamins/minerals  (CA,C,D,Selenium, OsteoBiflex, zinc,multi,E).

My new oncologist ran a CA27.29 test which showed a reading of 45 which is considered high.  Initially, he wanted to run a PET scan, but decided that we could rerun the test again in 3 months to see if the Lipitor or something else was affecting it.  If the number is higher, he says he would highly recommend the PET scan.

My concern with this test, which I did not realize was being run, is that I see that the CA27.29 is not only NOT conclusive for recurring cancer, but has a high rate of false positives.  I don't want any unnecessary tests done because I am scheduled for an orthopedic surgery after Christmas.  The general consensus seems to be that there is little value for this test with patients who have had breast cancer with my characteristics.  Also, there seem to be a huge number of other factors that can affect this reading, including production by your own body and I wonder if I should discontinue Lipitor, in case that is causing this high reading?.

So, I am wondering if my worry is well founded or if this test should even have been done!

[Cleveland Clinic]

Dear wiscan:  CA27.29 is a nonspecific marker for breast cancer.  The use of CA27.29 to detect breast cancer recurrence at present is controversial.  Increased levels could be due to a variety of reasons. In general, a new elevation of this tumor marker would prompt further evaluation. We do not routinely use the CA27.29 at our institution for follow-up of individuals with stage I cancer..

[wiscan]

Thank you for your reply.  

I still wonder about the need for this test.  The fact that you do not use it for diagnosis of cancer because of its unreliability is the standard answer among doctors I have talked with (except this particular oncologist) .Nothing seems to indicate this is a valuable test!   Almost everyone has told me that this test has many false positives and false negatives as well as it creates an environment where additional, invasive and potentially problematic testing might be recommended.   Therefore, if the test is so controversial and so unreliable, why would any oncologist do this test, especially on someone like me where all indications are that the cancer was definitely removed in the lumpectomy?  

I can't understand why anyone would recommend this test knowing it is unreliable and elevated numbers encourage new fears.