A Prospective Multi-Institutional Observational Study on ER, PR, HER2/NEU, and Ki-67 Expression and Discordance Pattern in Primary and Metastatic and Recurrent Carcinoma Breast and Its Therapeutic Implications and Prognostic Outcome.

Only few studies reported in literature that has elucidated in detail the implications of molecular typing in metastatic and recurrent breast cancer. In this prospective study, we have analysed in depth the pattern of expression, discordances of molecular markers in various metastatic sites, and recurrent cases and their response to chemotherapy/targeted agents and the prognostic outcome. The primary aim of the study was to determine ER, PR, HER2/NEU, and Ki-67 from recurrent and metastatic carcinoma breast to study the expression pattern and discordance and also to study the degree of discordance in relation to the site of metastasis and pattern of metastasis (synchronous vs metachronous) and discordance pattern with the response to chemotherapy and median overall survival rates in months in available subset of patients.