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Anastrozole ('Arimidex') blocks oestrogen synthesis both peripherally and within the breast in postmenopausal women with large operable breast cancer.

ABSTRACT: The effect of anastrozole on peripheral and tumour aromatase activity and oestrogen levels in postmenopausal patients with oestrogen receptor-rich breast tumours was investigated. Twenty-six patients were randomly allocated to treatment with anastrozole 1 mg (n=13) or 10 mg (n=13), once daily. Before and after 12 weeks' treatment, patients were infused with 3H-Delta4 androstenedione (20 MBq) and 14C-oestrone (E1) (1 MBq) for 18 h. Oestrogens were purified from excised tumours and plasma samples taken after each infusion. Peripheral and tumour aromatase activity and tumour E1 uptake were calculated from levels of 3H and 14C in purified E1 fractions from tumour and plasma. Endogenous tumour oestrogens were measured by radioimmunoassay. Twenty-three patients were available for analysis (1 mg group, n=12; 10 mg group, n=11). Following treatment, anastrozole (1 and 10 mg) markedly inhibited peripheral aromatase in all patients (the difference between pre- and on-treatment values being highly significant P<0.0001). In situ aromatase activity was also profoundly decreased by anastrozole treatment in 16 of 19 tumours (the difference with treatment also being highly significant P=0.0009). Most tumours were able to concentrate E1 beyond levels in the circulation; anastrozole treatment had no consistent effect on uptake of E1. Endogenous tumour levels of both E1 and oestradiol (E2) were significantly reduced with therapy (P=0.028 for E1 and P=0.0019 for E2). Anastrozole (1 and 10 mg daily) effectively suppresses aromatase activity, and subsequently oestrogen levels, within the breast tissue of postmenopausal women with large or locally advanced, operable, oestrogen receptor-rich breast cancers.

SUBMITTER: Miller WR

PROVIDER: S-EPMC2364315 | biostudies-other | 2002 Oct

REPOSITORIES: biostudies-other

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Project description:Older women are at the greatest risk of breast cancer development and a considerable number present with comorbidities. Although the majority of breast cancers in this age group express oestrogen receptor (ER), which makes endocrine therapy (primary or adjuvant) feasible, given the huge size of the elderly population, there remains a significant number of patients, in absolute term, whose tumours do not express ER and their management is challenging.Of a consecutive series of 1,758 older (?70 years) women with early operable primary breast cancer managed in a dedicated service from 1973-2010, 252(14.3%) had ER-negative (histochemical (H) score ?50) tumours. Their clinical outcome was retrospectively reviewed and tumour samples collected from diagnostic core biopsies were analysed for progesterone receptor (PgR), HER2 and Ki67 using immunohistochemistry.The commonest primary treatment was surgery (N = 194, 77%) followed by primary endocrine therapy (14.3%), primary radiotherapy (5.6%) and supportive treatment only (3.1%). Among the patients undergoing surgery, most of them had grade 3 (78.1%) and node-negative disease (62.2%). Some of them (21.1%) received postoperative radiotherapy. At a median follow-up of 37.5 months, 117 patients had died, out of which 48.6% were due to breast cancer. For those who underwent surgery, the regional and local recurrence rates were 2% and 1.1% per annum respectively. For those who received primary endocrine therapy, 38% progressed at 6 months, however all patients who had primary radiotherapy achieved clinical benefit at 6 months. Regardless of treatment given, the 5-year breast cancer specific and overall survival rates were 70% and 50% respectively. Biological analysis based on good quality needle core biopsy specimensfrom181 patients showed that 26.8% (N = 49), 16.9% (N = 31) and 70.7% (N = 70)expressed positivity for PgR, HER2 and Ki67 respectively. No correlation between these biomarkers and breast cancer specific survival was demonstrated.Oestrogen receptor negative early operable primary breast cancer in older women is associated with poor prognostic features in terms of biology and clinical outcome. Surgery appears to produce the best outcome as a primary treatment, however for those where neither surgery nor chemotherapy is appropriate, primary radiotherapy can be beneficial.

Project description:BACKGROUND:The diversity and composition of the gut microbiota may affect breast cancer risk by modulating systemic levels of oestrogens and inflammation. The current investigation tested this hypothesis in postmenopausal women by identifying breast cancer associations with an inflammation marker, oestrogen levels, and faecal microbes that were or were not coated with mucosal immunoglobulin A (IgA). METHODS:In this population-based study, we compared 48 postmenopausal breast cancer cases (75% stage 0-1, 88% oestrogen-receptor positive) to 48 contemporaneous, postmenopausal, normal-mammogram, age-matched controls. Microbiota metrics employed 16S rRNA gene amplicon sequencing from IgA-coated and -noncoated faecal microbes. High-performance liquid chromatography/mass spectrometry (HPLC/MS) and radioimmunoassay were used to quantify urine prostaglandin E metabolite (PGE-M), a possible marker of inflammation; urine oestrogens and oestrogen metabolites were quantified by HPLC/MS-MS. RESULTS:Women with pre-treatment breast cancer had non-significantly elevated oestrogen levels; controls' (but not cases') oestrogens were directly correlated with their IgA-negative microbiota alpha diversity (P=0.012). Prostaglandin E metabolite levels were not associated with case status, oestrogen levels, or alpha diversity. Adjusted for oestrogens and other variables, cases had significantly reduced alpha diversity and altered composition of both their IgA-positive and IgA-negative faecal microbiota. Cases' faecal microbial IgA-positive imputed Immune System Diseases metabolic pathway genes were increased; also, cases' IgA-positive and IgA-negative imputed Genetic Information Processing pathway genes were decreased (P?0.01). CONCLUSIONS:Compared to controls, breast cancer cases had significant oestrogen-independent associations with the IgA-positive and IgA-negative gut microbiota. These suggest that the gut microbiota may influence breast cancer risk by altered metabolism, oestrogen recycling, and immune pressure.

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Anastrozole ('Arimidex') blocks oestrogen synthesis both peripherally and within the breast in postmenopausal women with large operable breast cancer.

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