The ratio of urinary 11 -desoxy- 17 -oxo steroids to urinary corticosteroids (discriminant ratio, DR) was compared with levels of tumour oestrogen (ER) and progesterone (PR) receptor in 169 patients with early breast cancer. Approximately 20% of patients had significant levels in all three tests and 20% were negative by all three assays. However, patient status by ER and DR assay was in disagreement in 50% of cases. Retrospective analysis of 78 treatment courses of endocrine therapy in patients with disseminated breast cancer showed that out of the three predictive tests only ER assays reliably distinguished responding from non-responding patients. The same result was observed in a subgroup of 20 patients undergoing adrenal suppression with aminoglutethimide. When tests were combined in pairs, no combination, including either ER and PR or ER and DR, showed improved discrimination between responding and nonresponding patients compared to that seen with ER alone. No predictive assay or combination of assays could usefully distinguish patients with a high likelihood of response to endocrine therapy.
