Publications by authors named "Trevor Powles"

Two early observations about the first generation bisphosphonate, clodronate, suggested that it would likely have clinical utility; specifically, it was a more potent anti-resorptive but a less potent inhibitor of mineralisation than its predecessor etidronate. The known mechanism of action differs from that of the later nitrogen-containing bisphosphonates, as clodronate is metabolised intracellularly to a toxic analog of adenosine triphosphate, AppCCl2p, which causes mitochondrial dysfunction, impaired cellular energy metabolism and osteoclast apoptosis. For pre-clinical studies in a variety of disease models, liposomal clodronate has become the agent of choice for macrophage depletion, for example in a recent study to enhance haematopoietic chimerism and donor-specific skin allograft tolerance in a mouse model.

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The randomized, double-blinded Royal Marsden Tamoxifen Breast Cancer Prevention Trial in healthy high-risk women started in 1986 and is still blinded. Eligible participants ( = 2,471) were randomly assigned to tamoxifen (20 mg/d) or placebo for 8 years. Analysis in 2006 showed a 30% risk reduction of estrogen receptor (ER)-positive invasive breast cancer mostly in the posttreatment period.

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Purpose At least 94 common single nucleotide polymorphisms (SNPs) are associated with breast cancer. The extent to which an SNP panel can refine risk in women who receive preventive therapy has not been directly assessed previously. Materials and Methods A risk score on the basis of 88 SNPs (SNP88) was investigated in a nested case-control study of women enrolled in the International Breast Intervention Study (IBIS-I) or the Royal Marsden study.

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A case-control study from two randomised breast cancer prevention trials of tamoxifen and raloxifene (P-1 and P-2) identified single-nucleotide polymorphisms (SNPs) in or near genes ZNF423 and CTSO as factors which predict which women will derive most anti-cancer benefit from selective oestrogen receptor modulator (SERM) therapy. In this article, we further examine this question using blood samples from two randomised tamoxifen prevention trials: the International Breast Cancer Intervention Study I (IBIS-I) and the Royal Marsden trial (Marsden). A nested case-control study was designed with 2:1 matching in IBIS-I and 1:1 matching in Marsden.

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Background: Tamoxifen and raloxifene reduce the risk of breast cancer in women at elevated risk of disease, but the duration of the effect is unknown. We assessed the effectiveness of selective oestrogen receptor modulators (SERMs) on breast cancer incidence.

Methods: We did a meta-analysis with individual participant data from nine prevention trials comparing four selective oestrogen receptor modulators (SERMs; tamoxifen, raloxifene, arzoxifene, and lasofoxifene) with placebo, or in one study with tamoxifen.

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The Generations trial, a multicenter, placebo-controlled, double-blind trial, compared arzoxifene 20 mg/day and placebo in 9,354 postmenopausal women with osteoporosis (N=5,252) or low bone mass (N=4,102). Primary outcomes were vertebral fracture in the osteoporotic population and invasive breast cancer in all study participants. Here, we report the detailed breast cancer findings from the trial.

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The selective oestrogen receptor modulators (SERMs) tamoxifen has been shown to reduce the incidence of oestrogen receptor positive breast cancer by about 60 to 70% in healthy high risk women. The oestrogenic effects of tamoxifen caused a beneficial effect of reduced bone loss and fracture risk in postmenopausal women. However there was also significant gynaecological toxicity including an increased risk of endometrial cancer.

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Background: Currently available selective estrogen receptor modulators reduce the risk of breast cancer, but they are not widely used. In the Postmenopausal Evaluation and Risk-Reduction with Lasofoxifene (PEARL) trial, lasofoxifene was shown to reduce the risk of estrogen receptor-positive (ER+) breast cancer, nonvertebral and vertebral fractures, coronary artery disease, and stroke, but the effects on total breast cancer (invasive and ductal carcinoma in situ, ER+ and estrogen receptor-negative [ER-]) and ER+ invasive breast cancer are unknown.

Methods: Postmenopausal women (n = 8556) aged 59-80 years with low bone density and normal mammograms were randomly assigned to two doses of lasofoxifene (0.

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Arzoxifene is a selective estrogen receptor modulator (SERM) that has been shown to be more potent in preclinical testing than currently available agents. Its effects on clinical outcomes are not known. In a randomized, blinded trial, women aged 60 to 85 years with osteoporosis, defined as a femoral neck or lumbar spine bone mineral density T-score of -2.

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Background: The effects of lasofoxifene on the risk of fractures, breast cancer, and cardiovascular disease are uncertain.

Methods: In this randomized trial, we assigned 8556 women who were between the ages of 59 and 80 years and had a bone mineral density T score of -2.5 or less at the femoral neck or spine to receive once-daily lasofoxifene (at a dose of either 0.

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Breast cancer treatments have been associated with accelerated bone loss and increased osteoporosis risk. In a subgroup analysis of a randomised, double-blind, placebo-controlled study, we compared the changes in spine and total hip bone mineral density (BMD) and biochemical markers of bone turnover in women with primary breast cancer who had received standard therapy plus either oral clodronate 1600 mg/d (n=419) or placebo (n=432) for 2 years. After 2 years, spine BMD was 1.

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The development of breast cancer is dependant in part on oestrogen. Suppression of ovarian function or use of anti-oestrogens will reduce the incidence of breast cancer. Many trials have now been done involving tens of thousands of healthy women evaluating the use of selective oestrogen receptor modulators to reduce the risk of breast cancer in healthy women.

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In postmenopausal women, the use of aromatase inhibitors increases bone turnover and induces bone loss at sites rich in trabecular bone at an average rate of 1-3% per year leading to an increase in fracture incidence compared to that seen during tamoxifen use. The bone loss is much more marked in young women with treatment-induced ovarian suppression followed by aromatase inhibitor therapy (average 7-8% per annum). Pre-treatment with tamoxifen for 2-5 years may reduce the clinical significance of the adverse bone effects associated with aromatase inhibitors, particularly if this leads to a shortening in the duration of exposure to an aromatase inhibitor.

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Objective: To assess the safety and tolerability of a standardized 40 mg red clover isoflavone dietary supplement (Promensil, Novogen) in women with a family history of breast cancer to evaluate the feasibility of using the supplement for prevention of breast cancer in healthy women.

Study Design: Healthy women aged 35-70 years (n = 401) with at least one first-degree relative with breast cancer received red clover isoflavones or placebo for three years in a randomized, double-blind, placebo-controlled pilot trial. Participants were assessed clinically and blood samples taken for biochemical analysis every six months.

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Background: Several clinical trials have reported an early reduction in breast cancer incidence in healthy women using tamoxifen to reduce their risk of breast cancer but have not reported longer follow-up data for the evaluation of breast cancer prevention. We report the blinded 20-year follow-up (median follow-up = 13 years) of the Royal Marsden trial to identify any long-term prevention of breast cancer associated with tamoxifen treatment.

Methods: We randomly assigned 2494 healthy women to oral tamoxifen (20 mg/day) or placebo for 8 years.

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Bone is the most common site of metastatic spread from primary operable breast cancer, causing pain, fractures, and hypercalcemia. This spread depends on the release of osteolytic substances by the cancer cells, which activate osteoclasts to cause bone resorption. The osteoclasts also release growth factors that can act back on the cancer cells to activate growth.

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The First Cambridge Conference on Advances in Treating Metastatic Bone Cancer, a symposium held in Cambridge, Massachusetts, October 28 to 29, 2005, was convened to discuss recent advances and research related to the natural history of bone metastases and skeletal complications, bone cancer biology, treatment of myeloma and other solid tumors, and treatment-induced bone loss. The conference format combined brief presentations with extended periods of discussion. The conclusions reached during the 2-day meeting are summarized in this article and presented in more detail in the individual articles and accompanying discussion sessions that comprise the conference proceedings.

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Placebo controlled trials in over 25,000 women showed that tamoxifen reduced breast cancer risk by about 40% and osteoporotic fracture risk by about 32%. Similarly placebo controlled trials in nearly 18,000 women showed that raloxifene reduced breast cancer risk by 44-72% and osteoporotic fractures risk by 30-50%. A direct comparison of tamoxifen with raloxifene showed similar risk reduction for breast cancer and osteoporotic fractures with less toxicity for raloxifene.

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