OBJECTIVES:
Primary
* Describe estrogen levels (estradiol \[E2\], estrone \[E1\], and estrone sulphate \[E1S\]) at different time points during the first 4 years of treatment with triptorelin in combination with either tamoxifen citrate or exemestane on clinical trial IBCSG-2402 in premenopausal women with resected breast cancer.
* Assess whether there is a suboptimally estrogen-suppressed subgroup of patients who receive exemestane.
Secondary
* Compare estrogen levels (E2, E1, E1S) at different time points during treatment with triptorelin in combination with either tamoxifen citrate or exemestane.
* Examine potential predictive factors of ineffective estrogen suppression (e.g., age, chemotherapy \[yes/no\], type of chemotherapy received, smoking history, BMI, and evidence of menses at study entry).
* Investigate the predictive value of optimal estrogen suppression during the first 6 and 12 months of treatment with regard to long-term estrogen suppression (4-year period).
* Compare disease-free survival of suboptimally estrogen-suppressed patients treated with exemestane with that of patients with optimal suppression (exploratory analysis).
* Examine related endocrine function (FSH and LH) to further elucidate causes of suboptimal estrogen suppression.
OUTLINE: This is a multicenter study.
Blood samples are collected at baseline and at 3, 6, 12, 18, 24, 36, and 48 months for measurement of estrogen levels (estradiol \[E2\], estrone \[E1\], and estrone sulphate \[E1S\]) by gas chromatography-mass spectrometry and measurement of endocrine function (FSH and LH).
