Role of Pre-Operative Serum CA 15-3 Level in risk stratification of Breast Cancer

Background: Cancer Antigen 15-3, a derivative of a large transmembrane glycoprotein polymorphic epithelial mucin derived from MUC1 gene is a reliable marker in identifying patients who would benefit most from adjuvant therapy. Materials & Methods: Aimed at assessing the overall risk, possibility of distant metastasis and need for adjuvant therapy we assessed the role of pre-operative CA 15-3 and compared it with Nottingham's Prognostic Index (NPI) and the established prognostic markers like tumor size, lymph node status, histological grade, development of distant metastasis, death from disease. Results: We found no significant association between elevated pre-op CA 15-3 tumor size, histological grade and lymph node status when assessed separately, however, when these prognostic factors were combined together as Nottingham Prognostic Index (NPI), a significant association was established and also associated with a low 5 year survival rate. Patients with high pre-op CA 15-3 were the ones who developed distant metastasis in follow-up of 2 years and died due to breast cancer. Conclusions: Patients with elevated CA 15-3 preoperatively had poor outcome reflected by high NPI and early recurrence and this group of patients is most likely to benefit from adjuvant therapy. Patients in high risk group have significant risk of developing distant metastasis; low 5 year survival rate, high risk of death from disease and require intensive surveillance for early detection of distant metastasis.