Prognostic factors in primary breast cancer.

A review and update of published studies on oestrogen receptor and progesterone receptor as prognostic factors in breast cancer supports the following conclusions. In stage I breast cancer the lack of oestrogen receptor seems to be the most important factor for predicting earlier recurrence and poorer survival. In stage II breast cancer, measurement of progesterone receptor appears to be better than measurement of oestrogen receptor for predicting disease-free survival, and is as important as the oestrogen receptor in predicting overall survival. The benefits of adjuvant endocrine therapy are better predicted by the presence or absence of progesterone receptor rather than by oestrogen receptor. Measurement of proliferative activity (DNA S-phase) by thymidine labelling or flow cytometry, and of aneuploidy by flow cytometry, also provides prognostic information. The strong correlations between tumour receptor content, per cent S-phase and aneuploidy suggest that these measurements in concert might identify a subset of stage I breast cancer patients at increased risk for recurrence, who would thus be potential candidates for adjuvant therapy.