The role of follow-up CA15-3 in prognosis of breast cancer

Background: The purpose of this study is to confirm the usefulness of Cancer Antigen 15-3 (CA15-3) follow-up. We determine whether the change in the values of breast cancer tumor marker CA15-3 before and after treatment is useful as a prognostic factor for disease progression. Methods: We conducted a retrospective cohort study of female patients who were newly diagnosed with primary breast cancer. CA15-3 levels were checked 1 month preoperatively and at 1 year (Y) postoperatively. Disease-free survival and metastasis-free survival were analyzed according to CA15-3 levels and changes. Results: We analyzed the prognostic effect of the CA15-3 levels. Lymph node metastasis and postoperative 1Y CA15-3 levels were significant factors of disease-free survival. And elevated postoperative 1Y CA15-3 level was the only significant prognostic factor for metastasis-free survival. The study groups were classified into four subgroups according to the changes in CA15-3 level (preoperative–postoperative 1Y CA15-3). The normal-normal group showed the best disease-free and metastasis-free survival, while the elevated-elevated group showed the worst survival. Conclusions: We found that persistently high CA15-3 levels after the initial treatment might be a significant prognostic factors of worse breast cancer prognosis.