Normal (Left) Vs Tumour (Right) In Mammography Image
Tamoxifen is a estrogen receptor blocker, whereas the aromatase inhibitors block production of estrogen in places other than ovaries. Letrozole is one of the aromatase inhibitors, which block conversion of androgens like testosterone to estrogen. Ovaries directly produce estrogen without going to the stage of androgen, that is why letrozole acts in post-menoppausal women. All the female and male hormones are synthesized from cholesterol in different parts of body; ovary, fatty tissue(Adipose tissue), Breast and Adrenals.
Tamoxifen is usually prescribed for 2 to 3 years in case of estrogen receptor positive post menopausal women. Recurrence is also common in patients treated only with tamoxifen for variety of reasons. Though fairly well tolerated may have side effects on blood clotting mechanism and may stimulate endometrial cancer.
The recent Breast International Group (BIG) 1-98 trial on breast cancer patients for 12 years show that letrozole for three years following two years of tamoxifen therapy or latrozole alone for five years gives very good result in comparison to tamoxifen alone for five years.
Over a median of eight years of follow-up, women who were assigned to receive five years of letrozole after surgery had an 18% reduced risk of relapse and a 21% reduced risk of death compared with those assigned to receive tamoxifen," according to International Breast Cancer Study Group (IBCSG) Statistical and Data Management Center at the Dana-Farber Cancer Institute, Boston, MA, USA.
The IBCSG recently launched a long-term observational study that will extend patient follow-up for an additional five years in order to provide further information on efficacy and side effects of five years of adjuvant hormone therapy. "The follow-up study includes collection of yearly updates of survival, disease status and long-term adverse events.
This study is critically important as more than 74% of the patients enrolled in BIG 1-98 were still alive without a relapse at their most recent study visit.
First published in MedicalXpress as Aromatase inhibitor letrozole guards against breast cancer relapse for up to 8 years