Identifying breast cancer patients who require a double-check of preoperative core needle biopsy and postoperative surgical specimens to determine the molecular subtype of their tumor

Core needle biopsy (CNB) is a widely used procedure for breast cancer diagnosis and analyzing results of immunohistochemistry (IHC). Several studies have shown concordance or discordance in IHC results between CNB and surgical specimens (SS). A double-check (CNB and SS) is inefficient and costly to perform a double-check on all patients. Therefore, it is important to determine which patients would benefit from a double-check. We collected the medical records of patients who underwent breast cancer surgery at Pusan National University Yangsan Hospital between April 2009 and June 2018 (n = 620). Molecular subtypes were classified as follows by hormone receptors (HR) and human epidermal growth factor receptor-2 (HER2): HR+/HER2+, HR+/HER2-, HR-/HER2+, HR-/HER2-. Clinicopathological factors including age, obesity, histological grade, preoperative CEA, CA15-3, T stage, N stage, and menopausal status were assessed to determine whether they were associated with subtype change. Increasing histological grade (P < 0.001; odds ratio [OR], 3.693; 95% confidence interval [CI], 1.941-7.025), preoperative CEA ≥ 5 ng/mL (P =0.042; OR, 2.399; 95% CI, 1.009-5.707) and higher T stage (P = 0.015; OR, 2.241; 95% CI, 1.152-4.357) were significantly associated with subtype change. On multivariable analyses, subtype changes were more common in high-grade breast cancer (P < 0.001; OR, 1.077; 95% CI, 1.031-1.113) and CEA ≥ 5 (P = 0.032; OR, 2.658; 95% CI, 1.088-6.490). Patients with moderate- to high-grade tumors or CEA ≥ 5 ng/mL are required a double-check to determine the molecular subtype of breast cancer.