Background: Adjuvant therapy after surgery in breast cancer is based upon to the biologic characteristics of primary lesion. As we can see in the cell line data, the expression of estrogen receptor was significantly decreased in endocrine resistance c...
Background: Adjuvant therapy after surgery in breast cancer is based upon to the biologic characteristics of primary lesion. As we can see in the cell line data, the expression of estrogen receptor was significantly decreased in endocrine resistance cell lines. So the biologic characteristics of metastatic lesion after adjuvant therapy could be different with that of primary lesion. In the literature, the rate of discordance in progesterone receptor (PR) is about 30% and most of the patients have lost the biologic expression with metastasis or relapse. In this study, we tried to elucidate the change of biologic characteristics of breast cancer patients after relapse or metastasis. Methods: We reviewed medical record of relapsed/metastatic breast cancer patients who have diagnosed between 2003 and 2013. We enrolled 58 patients who have paired biopsy samples of primary site and metastatic sites and evaluated the clinical and biologic characteristics including site of relapse, site of biopsy, estrogen receptor(ER), PR, HER2 expression by immunohistochemistry or FISH and survival, retrospectively. Results: The median age of these patients is 48 years old (29~76) and the median time to re-biopsy from primary site tissue confirm was 27.5 months (0 ~265). The most common metastatic biopsied site is the chest wall and the second, third is lung and liver. The loss of ER, PR expression with metastasis was showed in 15.5 % and 13.8%, respectively. The gain of ER, PR, HER2 expression was showed in 3.4 %, 3.4 %, 5.2 %, respectively. Conclusions: Our study showed the discordance rate of 19.0 %, 17.2 %, 5.2 % in ER, PR, HER2 expression, respectively. So re-biopsy can guide the therapeutic options which might be differ to that of original breast cancer in relapsed/metastatic breast cancer.