Changes in biologic features between primary and recurrent breast cancers

Abstract

Background: Recent studies have shown that the expression status of hormone receptors and human epidermal growth factor receptor 2 (HER2) in breast cancer may change during disease progression. The aim of this study was to determine and compare the estrogen receptor (ER), progesterone receptor (PR), and HER2 expressions. Methods: Out of the patients with recurrence between 2004 and 2014, there were 34 patients from whom the lesion was resected and evaluated by immunostaining. Changes in the biological features between primary and recurrent disease based on disease free interval (DFI), site of biopsy, and adjuvant treatment were studied. Survival analyses were established according to the Kaplan Meier method, and groups were compared using the log‐lank test. Results: The median follow‐up time was 40.0 months (range 4‐159 months). The median age at breast cancer diagnosis was 53.0 (range 34‐80). ER, PR, and HER2 discordance between primary and recurrent tumors were found in 7 (20.6%), 10 (29.4%), and 3 (13.6%) patients respectively. Discordance rate was 55.5% in patients having DFI less than 2 years while 26.7% in patients having DFI greater than 5 years. Of patients without adjuvant therapy (n = 6), only 2 patients (33.3%) had ER, PR, or HER2 discordance while of patients receiving adjuvant therapy (n = 28), 15 patients (53.6%) had discordance. No significant difference of discordance rate was shown between local recurrence and distant metastasis. There was no statistically difference in survival ratio whether if biological marker changes or not. Conclusions: Patients with breast cancer experience change in biological markers through the course of their disease. Changes in biological features may influence treatment decisions taken at recurrence and re‐biopsy should be considered if feasible.