High Levels of Serum CA15-3 and Residual Invasive Tumor Size Are Associated with Poor Prognosis for Breast Cancer Patients with Non-pathological Complete Response After Neoadjuvant Chemotherapy

Background And Objectives: To identify surrogate markers for prognosis of breast cancer patients with non-pathological complete response (non-pCR) to neoadjuvant chemotherapy (NAC), our investigation focused on the serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen (CA15-3) as well as clinicopathological factors both before and after NAC.

Methods: A total of 185 breast cancer patients treated with NAC were recruited. Serum carcinoembryonic antigen and CA15-3 were measured at baseline and at completion of NAC.

Results: Among the non-pCR cancers (n = 142), the disease-free survival (DFS) of patients with CA15-3-low at baseline (3-year DFS: 0.908, n = 73) was significantly better than of those with CA15-3-high (3-year DFS: 0.681, n = 69, P = .0134). Multivariable analysis demonstrated that baseline CA15-3 levels (hazard ratio: 3.31, 95% confidence interval: 1.28-10.23; P = .0122) and residual invasive size (hazard ratio: 4.47, 1.26-28.39; P = .0171) were significant independent factors for DFS. The combination of these factors proved to be an accurate predictor for DFS regardless of breast cancer subtypes.

Conclusions: The combination of residual invasive size and serum CA15-3 levels at baseline seems to be a significant and independent surrogate marker of poor outcome for patients with non-pCR. These findings suggest that these markers may be useful for identifying patients with inferior prognosis and candidates for additional adjuvant treatments.