Trial Information

A Substudy of the IBCSG 24-02/ SOFT Trial to Investigate Estrogen Suppression for Patients Participating in Arms B and C of the IBCSG 24-02/ SOFT Trial

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).