Elevated preoperative serum cancer antigen 15.3 levels are associated with reduced disease-free survival: a single-institution experience

Eyad Fawzi Alsaeed,¹ Huda Abdulkarim,² Mutahir A Tunio<sup>3

1</sup>Radiation Oncology Department, King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia; ²Department of Medical Oncology, ³Department of Radiation Oncology, King Fahad Medical City, Riyadh, Saudi Arabia

Background: We aimed to evaluate the prognostic significance of the preoperative tumor-marker cancer antigen (CA) 15.3 in Saudi patients with breast cancer and to find out whether any correlation exists between preoperative CA 15.3 and tumor size and nodal status.
Materials and methods: Preoperative blood samples for serum CA 15.3 levels were taken in 112 breast cancer patients who underwent breast-conserving surgery or modified radical mastectomy between February 1988 and August 2008. Serum levels of CA 15.3 below 35 U/mL were considered normal. The correlation between pre- and postoperative CA 15.3 levels with tumor size and nodal status was calculated using Pearson correlative coefficients. Kaplan–Meier curves were used to determine disease-free survival (DFS) according to CA 15.3 groups (<35, 36–100 and above >100 U/mL).
Results: The mean age of the cohort was 47.0 years (range 23–76, standard deviation 10.3). According to menopausal status, 93 patients (83.0%) were premenopausal, and 19 patients (17.0%) were postmenopausal. Mean preoperative CA 15.3 levels were 43.69 U/mL (1.0–209.87). Ten-year DFS rates were 100%, 84%, and 57.7% for CA 15.3 <35 U/mL, 36–100 U/mL, and >100 U/mL, respectively (P = 0.003). Preoperative CA 15.3 levels showed positive correlation with primary tumor size (R = 0.43, R² = 0.83, P = 0.03) and nodal status (R = 0.59, R² = 0.28, P < 0.0001), respectively.
Conclusion: Elevated preoperative CA 15.3 above 35 U/mL in Saudi women breast cancer patients showed correlation with primary tumor size and nodal status, and preoperative CA 15.3 level is an independent prognostic factor for DFS. Preoperative serum CA 15.3 levels may be helpful for risk stratification along with other factors.

Keywords: breast cancer, preoperative serum CA 15.3 levels, correlation, disease-free survival