what exactly does Ca15-3 measure and should it show response to chemo?

[Lani]

1: BMC Cancer. 2006 Sep 5;6(1):220 [Epub ahead of print] Links
CA 15-3 is predictive of response and disease recurrence following treatment in locally advanced breast cancer.

Al-Azawi D,
Kelly G,
Myers E,
McDermott EW,
Hill AD.
ABSTRACT: BACKGROUND: Primary chemotherapy (PC) is used for down-staging locally advanced breast cancer (LABC). CA 15-3 measures the protein product of the MUC1 gene and is the most widely used serum marker in breast cancer. METHODS: We retrospectively investigated the role of CA 15-3 in conjunction with other clinico-pathological variables as a predictor of response and time to disease recurrence following treatment in LABC. Pre and post primary chemotherapy serum concentrations of CA 15-3 together with other variables were reviewed and related to four outcomes following primary chemotherapy (clinical response, pathological response, time to recurrence and time to progression). Persistently elevated CA 15-3 after PC was considered as consecutively high levels above the cut off point during and after PC. RESULTS: 73 patients were included in this study. Patients received PC (AC or AC-T regimen) for locally advanced breast cancer. 54 patients underwent surgery. The median follow up was 790 days. Patients with high concentrations of CA 15-3 before PC treatment had a poor clinical (p=0.013) and pathological (p=0.044) response. Together with Her-2/neu expression (p= 0.009) and tumour lympho-vascular space invasion (LVI) (p= 0.001), a persistently elevated CA 15-3 post PC (p=0.007) was an independent predictive factor of recurrence following treatment in LABC. CONCLUSIONS: Elevated CA 15-3 level is predictive of a poor response to chemotherapy. In addition, persistently elevated CA 15-3 levels post chemotherapy in conjunction with lympho-vascular invasion and HER2 status predict a reduced disease free survival following treatment in locally advanced breast cancer.
PMID: 16953875 [PubMed - as supplied by publisher]

[Carina]

Lani,

Thanks for the information. Do you know how CA15-3 levels are measured? Has anyone had this done?

Though I believe that each person's situation is unique and we are more than an accumulation of stats, I would like to know.

Carina

[Lani]

Some oncologists don't want to measure it in those patients who are not metastatic , as it makes patients nervous and "we aren't going to do anything differently anyway" This study in patients with locally advanced breast cancer shows it can differentiate those in which a particular course of chemotherapy is not working, in order to try another and a subset of patients in whom recurrence is very likely, perhaps in order to place them into a clinical trial for something new.

As I understand it the vast majority of breast cancer cells express MUC-1 (they are looking into it as a new target of treatment)

So it is nice to know that that is the basis of the serum test and that it seems to be accurate in following breast cancer response to treatment and predictiing prognosis.

[Carina]

Thanks for the clear answer. I will discuss it with my doctor. I like to know what I am facing.

Carina

[tousled1]

My oncologist will do the test anytime I ask for it but she does not believe you should rely on them. Remember there are a lot of things that can affect the results - low counts, being on an antibiotic, etc. When used in conjunction with other tests it can be useful.