Elevated CA 15.3 in Newly Diagnosed Breast Cancer: A Retrospective Study

Abstract

In this study, the relationship between baseline elevated serum CA 15.3(>30 kU/L) and the prevalence of primary or secondary metastatic disease in breast cancer is examined. A total of 894 breast cancer patients were included, median follow-up time was 74 months: 38% had primary metastatic disease, 15% developed secondary metastatic disease during followup. Purpose: To examine the relationship between baseline elevated CA 15.3 (>30 kU/L) and the prevalence of primary or secondary metastatic disease in breast cancer. Methods: We performed a retrospective, single-center cohort study on patients with newly diagnosed breast cancer and baseline CA 15.3, 30 kU/L, diagnosed between 2000-2015. Information on tumor characteristics, pre-treatment CA 15.3, staging results, treatment approach, disease recurrence and death were collected from individual medical files. For every tumor subtype, the optimal cut-off value of CA 15.3 for determining primary metastatic disease is determined. Results: Eight hundred ninety-four patients with baseline CA15.3 , 30 kU/L were included of which 38% were diagnosed with primary metastatic disease while 15% subsequently developed secondary metastatic disease, with a median follow-up of 74 months. Luminal-HER2 tumors had the highest proportion of primary metastatic disease (48%), Triple Negative tumors had the highest proportion of secondary metastatic disease (24%) (p=0.008). A higher CA 15.3 value corresponds to higher risk of both primary and secondary metastatic disease (p<0.001). For the determination of primary metastatic disease, optimal cut-off values for CA 15.3 range between 44 kU/L (Triple Negative) and 59 kU/L (Luminal B). Conclusion: In patients with newly diagnosed breast cancer and baseline elevated CA 15.3 >30 kU/L, 38% presents with primary metastatic disease and 15% develops secondary metastatic disease, with a median follow-up of 74 months. Our results can help clinicians to identify patients at risk of primary or secondary metastatic disease via information on tumor subtype and baseline CA 15.3. (C) 2022 Elsevier Inc. All rights reserved.