RESUMEN
Changes in ER, PR and Her2 receptor status between primary and metastatic cancer tissue have been suggested in breast cancer. The frequencies of these changes are still not fully understood. The purpose of this study was to evaluate these changes in breast cancer population of Kuwait. Changes in the biological features between primary and recurrent disease in 70 patients who presented between 2009 and 2012 was studied. Statistical comparisons between groups was done using chi square test while Kaplan Meier method was used to perform analysis of survival after relapse. All analysis was carried out using the IBM-SPSS statistical software. There was a decrease in ER and PR positivity from 61.4% to 58.6% and 61.4% to 44.3% respectively. The overall change in ER and PR status was 28.5% and 25.7% respectively. There was an increase in the Her2 positivity as the tumor relapsed and overall changes were seen in 5.7% of cases. Patients with breast cancer experience change in biological markers through the course of their disease. The changes are more with hormone receptors compared to Her2. Re-biopsy should be considered at relapse if feasible