Independent factors predict supranormal CA 15-3 serum levels in advanced breast cancer patients at first disease relapse

Data currently available are insufficient to demonstrate a real utility for CA 15-3 in the diagnosis, staging or surveillance of breast cancer patients following primary treatment. The aim of this study was to determine if there was a correlation between supranormal CA 15-3 serum levels and clinical and biological variables in breast cancer patients at first disease relapse. From October 1988 to March 1998, 430 consecutive patients entered the study. Overall CA 15-3 sensitivity was 60.7%. Elevated CA 15-3 levels were found more frequently in patients with liver metastases (74.6%) and in those with pleural effusion (75.7%). CA 15-3 sensitivity was 70.4% in patients with estrogen-receptor-positive (ER+) primary tumors and 45.9% in those with estrogen-receptor-negative (ER-) tumors (p < 0.0001). In patients with a limited extent of disease, marker sensitivity was 57.7% in ER+ tumors and 25.7% in ER- tumors (p < 0.0001). Logistic regression analysis showed ER status, disease extent and pleural effusion as independent variables associated with CA 153 positivity. The multivariate Cox analysis showed ER and disease extent as independent variables predicting overall survival, whereas CA 15-3 failed to be statistically significant. CA 15-3 was an independent variable only when the disease extent variable was removed. This study suggests that CA 15-3 in advanced breast cancer patients is a marker of both disease extent and ER status. The direct relationship with ER status indicates that CA 15-3 diagnostic sensitivity in the early detection of disease recurrence could be greater in ER+ patients than in ER- ones. Furthermore, this suggests that patients with elevated CA 15-3 levels could have disease that is more sensitive to hormone manipulation than those with normal CA 15-3 values. Copyright (C) 2001 S. Karger AG, Basel.