[Changing behavior of estrogen and progesterone receptors with metastasis or recurrence of breast cancer]

Changes in level of estrogen receptor (ER) and progesterone receptor (PgR) and their affecting factors were studied with metastasis or recurrence of breast cancer. Since 1983, from 177 patients, 443 specimens were obtained and 244 simultaneous and 122 sequential pairs were compared. The consistency rate was 81% for both ER and PgR with simultaneous comparison,and 69% for ER and 71% for PgR with sequential comparison, mainly due to positive-to-negative change, and less than 10% of negative-to-positive change. Positive-to-negative change was prominent with intervening endocrine treatment, and it was significant (p=0.015) for ER by multiple regression analysis of age, interval of sampling and from prior surgery, intervening chemotherapy, endocrine therapy and human epidermal growth factor receptor 2 (HER 2). Based on recent data of ER and PgR, feasible treatment seems to be planned, because about 30% of them are different from that of primary lesion.