Relative importance of estrogen and progesterone receptor assays as prognostic indicators in primary breast cancer: a short-term study.

This short-term study of the relative importance of estrogen and progesterone receptors shows that progesterone receptor correlates better than estrogen receptor with tumor recurrence regardless of lymph-node status. Life-table analysis has effectively identified only two groups of patients that may be classified by progesterone receptor status alone. Progesterone-receptor negativity correlated well with tumors of histological Grade III; estrogen-receptor positivity correlated with Grade I and II tumors. The earlier recurrence of Grade III breast tumors may explain why progesterone receptor is a better prognostic indicator than estrogen receptor in short-term studies.