The prognostic value of the tumor marker CA 15-3 at initial diagnosis of patients with breast cancer.

CA 15-3 has been most widely used as a serum tumor marker in follow-up and detection of breast cancer recurrence. In this study we have specifically focused upon the prognostic implications and utility of preoperative CA 15-3 levels. We have identified on our database 414 patients with breast cancer in whom serial levels of the serum tumor marker CA 15-3 had been determined at diagnosis and follow-up. We have analyzed the follow-up and clinical outcomes in these patients and from this data we have assessed the potential of CA 15-3 as a predictor of five-year overall and disease-free survival. Our results show that an initially elevated CA 15-3 level is associated with a very poor prognosis in both early and late stage disease. Elevated pre-biopsy CA 15-3 levels are associated with 14% five-year disease-free survival rates and 17% overall survival rates at five years. In contrast, normal CA 15-3 levels are associated with 47% five-year disease-free survival rates and 54% overall survival rates at five years (p<0.01). Comparison of five-year survival rates between patients with elevated and normal CA 15-3 levels in early breast cancer (stage I and II) also showed significant differences, with survival being 41% and 75%, respectively (p<0.01).