PREDICTORS OF RESPONSE TO 2ND-LINE ENDOCRINE THERAPY FOR BREAST-CANCER

This study reports on factors predicting response to second-line endoc rine therapy in 250 patients with breast cancer for which they were as sessable for response by the International Union Against Cancer (UICC) criteria. Clinical details relating to first-line endocrine therapy w ere available for all patients. We have not included in this study pat ients who received first-line endocrine therapy but did not or have no t yet proceeded to second-line hormone therapy - e.g. died from rapidl y progressive disease, started chemotherapy for rapidly progressive di sease, or remained in long-term remission on first-line endocrine ther apy. One hundred and fifty nine patients (72%) achieved remission (obj ective response and static disease [OR + SD]) on first-line endocrine therapy with a median duration of 19 months. For second-line endocrine therapy the remission rate was 53% (132/225) with a median duration o f 15 months. Tumour grade and oestrogen receptor status of the primary tumour were shown to be independent predictors of response to second- line endocrine therapy while response to first-line endocrine therapy was a predictor of the duration of response to second-line endocrine t herapy. In the sub-group of patients who showed OR or SD to both first and second-line therapies, there was no correlation between the time to progression (TTP) on first and second-line therapies.