The International Breast Cancer Study Group ( IBCSG ) has presented results of the randomized phase III SOFT trial at the 2014 San Antonio Breast Cancer Symposium.
Suppression of Ovarian Function Trial ( SOFT ) assessed the value of ovarian suppression in reducing breast cancer recurrence in young women receiving Tamoxifen, and evaluated the role of the aromatase inhibitor Exemestane ( Aromasin ) plus ovarian suppression in this population.
Ovarian suppression was obtained entirely by monthly injections of Triptorelin ( Decapeptyl ) over 5 years for 81% of patients.
Treatment combining Tamoxifen plus ovarian suppression reduced the relative risk of developing invasive breast cancer recurrence by 22% in women who did not transition into menopause after receiving chemotherapy, when compared to treatment with Tamoxifen alone. On average, these women were 40 years old when starting hormonal therapy after chemotherapy.
A secondary analysis revealed that further benefit could be gained by treating these women with Exemestane plus ovarian suppression, which reduced their relative risk of breast cancer recurrence by 35%, compared to Tamoxifen alone, resulting in 7 or 8 fewer women out of 100 having a breast cancer recurrence within 5 years.
SOFT trial enrolled more than 3,000 premenopausal women with hormone receptor-positive early-stage breast cancer and estradiol levels in the premenopausal range during the period 2003-2011. Trial treatment lasted 5 years and women continue to be followed for life to assess long-term prognosis and side effects.
SOFT was designed to assess the value of ovarian suppression in reducing breast cancer recurrence in young women receiving Tamoxifen, and to assess the role of the aromatase inhibitor Exemestane plus ovarian suppression in treating young women.
Premenopausal women with estrogen and/or progesterone receptor-positive, breast cancer were randomly assigned to treatment with Tamoxifen alone for 5 years, Tamoxifen plus ovarian suppression for 5 years, or Exemestane plus ovarian suppression for 5 years.
Triptorelin, active substance of Decapeptyl, is a decapeptide analogue of GnRH ( Gonadotrophin Releasing Hormone ), a hormone secreted by the hypothalamus, which initially stimulates the release of pituitary gonadotrophins which in turn control hormonal secretions by the testicules and ovaries.
Administration of Triptorelin results in the suppression of the GnRH activity leading to menopause in women and hormonal castration in men. ( Xagena )
Source: Ipsen, 2014