Abstract
Out of 52 cases of breast cancer whose primary tumors had been examined with regard to estrogen receptors (ER) in multiple portions, 12 cases showed recurrence after radical mastectomy. In this study, the relationship between inter-site variation of ER and the effect of endocrine therapies was studied in the 12 recurrent breast cancers.
In six of the 12 cases, ER were measured only in the central and peripheral portions. All of them were negative or showed only low levels even if they were positive.
ER of the other six cases out of the 12 were measured in the central, peripheral, largest cross-section and/or whole tumor (a mixture of cytosols from multiple sites within the tumor). Three of the 6 cases, which were ER-negative in all portions, did not respond. The other 3 cases showed inter-site variation of ER because of the difference of ER status in the central and peripheral portions in each case.
Two of the 3 cases were non-responsive ; one was ER-negative for whole tumor and the other was ER-boderline for largest cross-section. The remaining ER-positive case responded for largest cross-section.
These results showed that ER assay at the largest cross-section within large tumors was most useful for predicting the effect of endocrine therapy.
