Primary hormonal therapy of advanced breast cancer with megestrol acetate: predictive value of estrogen receptor and progesterone receptor levels.
Estrogen (ER) and progesterone receptor (PR) levels in human breast cancer have been shown to have value in predicting response to a variety of hormonal therapies. However, the relationships between steroid receptor levels and tumor response and survival in patients treated with progestational agents for primary hormonal therapy have not been clearly defined. Forty-three advanced breast cancer patients, whose tumors had been assayed for ER and PR were treated with megestrol acetate as initial hormonal therapy. Twenty-five patients had ER and PR levels greater than 10 femtomole/mg cytosol protein, and the median ER and PR levels for the entire group were 114 fmol/mg and 100 fmol/mg, respectively. The overall response rate (complete and partial) was 46%, with a median duration of response of 66 weeks. Seventy percent of patients whose ER and PR were greater than 10 fmol/mg responded: Step-wise discriminant analysis showed that ER and PR were significantly related to response and that PR was the best predictor of response (P = .0034). Similarly, both ER and PR were significantly related to survival (P = .0001 for PR and P = .021 for ER). These data indicate that megestrol acetate is effective primary hormonal therapy in advanced breast cancer patients, and that ER and PR levels were significantly related to response and to survival duration. PR proved to be the best predictor of response in this group of patients.
D000368:Aged; D001943:Breast Neoplasms / Q000032:analysis / Q000188:drug therapy* / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008535:Megestrol / Q000031:analogs & derivatives* / Q000627:therapeutic use; D019290:Megestrol Acetate; D008875:Middle Aged; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*
D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D008535:Megestrol; D019290:Megestrol Acetate