Evaluation of Biomarkers Changes in Recurrent Breast Cancer

Abstract

Background: Obtaining tumor specimens and re-evaluation targeted markers is recommended, if possible, in breast cancer patients who relapsed after curative treatment. The biomarkers status changes in rebiopsied tumors have been demonstrated to have considerable clinical implications.

Objectives: To identify the changes of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status between the primary and recurrent lesions.

Materials and Methods: We conducted a study among 67 patients with recurrent breast cancer, recruited from 2015 to 2020 in Al-Mouasat and Al-Asad University Hospitals in Damascus to compare ER, PR, and HER2 status between the primary and recurrent lesions. For each patient, a specimen of their primary tumor and another specimen of recurrent lesions underwent pathological assessment. Immunohistochemistry (IHC) was performed to determine ER, PR, and HER2 status in both specimens.

Results: Biomarker status conversion rates (in both directions) between primary and recurrent tumors were 26.9% for ER, 38.8% for PR, and 22.4% for HER2. Overall, IHC subtypes (hormone receptor positive, HER2 amplified, and triple-negative) changed in 25 out of 67 (37.3%) cases. Conversion rates were not statistically significantly different between patients with different recurrent sites and times of recurrence. Eight out of 13 initially triple-negative patients (61.5%) had a change to positive status of either ER, PR, or HER2.

Conclusion: A substantial discordance in ER, PR, and HER2 status were observed between primary breast cancer tissues and recurrent lesions. Rebiopsy could bring new therapeutic opportunities in the management of

patients with recurrent breast cancer.