CA 15-3 is predictive of response and disease recurrence following treatment in locally advanced breast cancer

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.

Conclusion: 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.

Figure 1

Kaplan-Meiers survival curve shows that presence of LVI is significantly associated with shorter time to recurrence (p = 0.001 Cox model).

Figure 2

Kaplan-Meiers survival curve, the expression of Her-2/neu receptor was associated with a decrease in disease free time (p = 0.009 Cox model).

Figure 3

Kaplan-Meiers survival curve shows post PC high serum levels of CA15-3 (CA15-3^a levels ≤ 30 KU/L, CA15-3^b ≥ 30 KU/L) was associated with early disease recurrence (p = 0.007 Cox model).