Trevor J. Powles

Interim analysis of the incidence of breast cancer in the Royal Marsden Hospital tamoxifen randomised chemoprevention trial

BACKGROUND Tamoxifen, a drug with antioestrogenic effects, is predicted to prevent the occurrence of breast cancer. We have undertaken a trial of tamoxifen in healthy women who are at increased risk of breast cancer because of family history. We report a planned interim analysis. METHODS Between October, 1986, and April, 1996, we accrued 2494 healthy women aged between 30 and 70 with a family history of breast cancer. They have been randomised (double blind) to receive tamoxifen 20 mg per day orally or placebo for up to 8 years. Follow-up included clinical assessment, annual mammography, and assessment of toxicity and compliance. The primary endpoint was the occurrence of breast cancer, which was analysed on an intention-to-treat basis with a survival curve. FINDINGS With a median follow-up of 70 months, 2471 women (tamoxifen 1238, placebo 1233) were suitable for analysis. The groups were evenly matched at baseline, and compliance was good. The overall frequency of breast cancer is the same for women on tamoxifen or placebo (tamoxifen 34, placebo 36, relative risk 1.06 [95% CI 0.7-1.7], p=0.8). Participants who were already on hormone-replacement therapy when they entered the study had an increased risk of breast cancer compared with non-users. Those participants who started such therapy while on trial had a significantly reduced risk. The safety profile of tamoxifen was as expected. INTERPRETATION We have been unable to show any effect of tamoxifen on breast-cancer incidence in healthy women, contrary to the report from the NSABP-P1 study showing a 45% reduction in healthy women given tamoxifen versus placebo. Differences in the study populations for the two trials may underlie these conflicting findings: eligibility in our trial was based predominantly on a strong family history of breast cancer whereas in the NSABP trial was mostly based on non-genetic risk factors. The importance of oestrogen promotion may vary between such populations.

Continued breast cancer risk reduction in postmenopausal women treated with raloxifene: 4-year results from the MORE trial

Raloxifene, a selective estrogen receptor modulator approved for the prevention and treatment of postmenopausal osteoporosis, has shown a significant reduction in breast cancer incidence after 3 years in this placebo-controlled, randomized clinical trial in postmenopausal women with osteoporosis. This article includes results from an additional annual mammogram at 4 years and represents 3,004 additional patient-years of follow-up in this trial. Breast cancers were ascertained through annual screening mammograms and adjudicated by an independent oncology review board. A total of 7,705 women were enrolled in the 4-year trial; 2,576 received placebo, 2,557 raloxifene 60mg/day, and 2,572 raloxifene 120mg/day. Women were a mean of 66.5-years old at trial entry, 19 years postmenopause, and osteoporotic (low bone mineral density and/or prevalent vertebral fractures). As of 1 November 1999, 61 invasive breast cancers had been reported and were confirmed by the adjudication board, resulting in a 72% risk reduction with raloxifene (relative risk (RR) 0.28, 95% confidence interval (CI) 0.17, 0.46). These data indicate that 93 osteoporotic women would need to be treated with raloxifene for 4 years to prevent one case of invasive breast cancer. Raloxifene reduced the risk of estrogen receptor-positive invasive breast cancer by 84% (RR 0.16, 95% CI 0.09, 0.30). Raloxifene was generally safe and well-tolerated, however, thromboembolic disease occurred more frequently with raloxifene compared with placebo (p=0.003). We conclude that raloxifene continues to reduce the risk of breast cancer in women with osteoporosis after 4 years of treatment, through prevention of new cancers or suppression of subclinical tumors, or both. Additional randomized clinical trials continue to evaluate this effect in postmenopausal women with osteoporosis, at risk for cardiovascular disease, and at high risk for breast cancer.

Effect of tamoxifen on bone mineral density measured by dual-energy x-ray absorptiometry in healthy premenopausal and postmenopausal women.

PURPOSE Tamoxifen is an effective treatment for metastatic and primary breast cancer and is now being evaluated as a chemoprevention agent in healthy women. Any long-term effects on estrogen-sensitive tissues such as bone may have important therapeutic implications. METHODS We measured bone mineral density (BMD) in the lumbar spine and hip using dual-energy x-ray absorptiometry (DXA) in premenopausal and postmenopausal healthy women who participated in our placebo-controlled tamoxifen chemoprevention of breast cancer trial. RESULTS BMD data are now available from 179 women for this analysis. In premenopausal women, BMD decreased progressively in the lumbar spine (P < .001) and in the hip (P < .05) for women on tamoxifen, but not those on placebo. The mean annual loss in lumbar BMD per year over the 3-year study period in tamoxifen-treated compliant women who remained premenopausal throughout the study period was 1.44% (1.88% calculated on an intent-to-treat basis) compared with a small gain of 0.24% per annum for women on placebo (P < .001). Tamoxifen had the opposite effect in postmenopausal women. The mean annual increase in BMD for women on tamoxifen was 1.17% in the spine (P < .005) and 1.71% in the hip (P < .001) compared with a noninsignificant loss for women on placebo. CONCLUSION These results indicate that tamoxifen treatment is associated with a significant loss of BMD in premenopausal women, whereas it prevents bone loss in postmenopausal women. These adverse and beneficial effects of tamoxifen should be considered in the assessment of the therapeutic benefits for both the adjuvant treatment and the chemoprevention of breast cancer.

Randomized, placebo-controlled trial of clodronate in patients with primary operable breast cancer.

PURPOSE The development of bone metastases depends on tumor-induced osteoclastic resorption of bone, which may be inhibited by the antiosteolytic bisphosphonate clodronate. Given to patients with primary breast cancer, clodronate might reduce the subsequent incidence of bone metastases. PATIENTS AND METHODS This double-blind, multicenter trial accrued 1,069 assessable patients with operable breast cancer between 1989 and 1995. All patients received surgery, radiotherapy, chemotherapy, and tamoxifen as required. Patients were randomized to receive oral clodronate 1,600 mg/d or a placebo for 2 years starting within 6 months of primary treatment. The primary end point was relapse in bone, analyzed on an intent-to-treat basis, during the medication period and during the total follow-up period (median follow-up, 2,007 days). Secondary end points were relapse in other sites, mortality, and toxicity. RESULTS During the total follow-up period, there was a nonsignificant reduction in occurrence of bone metastases (clodronate, n = 63; placebo, n = 80; hazards ratio [HR], 0.77; 95% confidence interval [CI], 0.56 to 1.08; P =.127). During the medication period there was a significant reduction in the occurrence of bone metastases (clodronate, n = 12; placebo, n = 28; HR, 0.44; 95% CI, 0.22 to 0.86; P =.016). The occurrence of nonosseous metastases was similar (clodronate, n = 112; placebo, n = 128; P =.257), but there was a significant reduction in mortality (clodronate, n = 98; placebo, n = 129; P =.047) during the total follow-up period. CONCLUSION Clodronate, given to patients with primary operable breast cancer, may reduce the occurrence of bone metastases, although this reduction was only significant during this medication period. There was a significant reduction in mortality.

Lasofoxifene in Postmenopausal Women with Osteoporosis

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 0.25 mg or 0.5 mg) or placebo for 5 years. Primary end points were vertebral fractures, estrogen receptor (ER)-positive breast cancer, and nonvertebral fractures; secondary end points included major coronary heart disease events and stroke. RESULTS Lasofoxifene at a dose of 0.5 mg per day, as compared with placebo, was associated with reduced risks of vertebral fracture (13.1 cases vs. 22.4 cases per 1000 person-years; hazard ratio, 0.58; 95% confidence interval [CI], 0.47 to 0.70), nonvertebral fracture (18.7 vs. 24.5 cases per 1000 person-years; hazard ratio, 0.76; 95% CI, 0.64 to 0.91), ER-positive breast cancer (0.3 vs. 1.7 cases per 1000 person-years; hazard ratio, 0.19; 95% CI, 0.07 to 0.56), coronary heart disease events (5.1 vs. 7.5 cases per 1000 person-years; hazard ratio, 0.68; 95% CI, 0.50 to 0.93), and stroke (2.5 vs. 3.9 cases per 1000 person-years; hazard ratio, 0.64; 95% CI, 0.41 to 0.99). Lasofoxifene at a dose of 0.25 mg per day, as compared with placebo, was associated with reduced risks of vertebral fracture (16.0 vs. 22.4 cases per 1000 person-years; hazard ratio, 0.69; 95% CI, 0.57 to 0.83) and stroke (2.4 vs. 3.9 cases per 1000 person-years; hazard ratio, 0.61; 95% CI, 0.39 to 0.96) Both the lower and higher doses, as compared with placebo, were associated with an increase in venous thromboembolic events (3.8 and 2.9 cases vs. 1.4 cases per 1000 person-years; hazard ratios, 2.67 [95% CI, 1.55 to 4.58] and 2.06 [95% CI, 1.17 to 3.60], respectively). Endometrial cancer occurred in three women in the placebo group, two women in the lower-dose lasofoxifene group, and two women in the higher-dose lasofoxifene group. Rates of death per 1000 person-years were 5.1 in the placebo group, 7.0 in the lower-dose lasofoxifene group, and 5.7 in the higher-dose lasofoxifene group. CONCLUSIONS In postmenopausal women with osteoporosis, lasofoxifene at a dose of 0.5 mg per day was associated with reduced risks of nonvertebral and vertebral fractures, ER-positive breast cancer, coronary heart disease, and stroke but an increased risk of venous thromboembolic events. (ClinicalTrials.gov number, NCT00141323.)

Gene expression profiles derived from fine needle aspiration correlate with response to systemic chemotherapy in breast cancer

BackgroundDrug resistance in breast cancer is a major obstacle to successful chemotherapy. In this study we used cDNA microarray technology to examine gene expression profiles obtained from fine needle aspiration (FNA) of primary breast tumors before and after systemic chemotherapy. Our goal was to determine the feasibility of obtaining representative expression array profiles from limited amounts of tissue and to identify those expression profiles that correlate with treatment response.MethodsRepeat presurgical FNA samples were taken from six patients who were to undergo primary surgical treatment. Additionally, a group of 10 patients who were to receive neoadjuvant chemotherapy underwent two FNAs before chemotherapy (adriamycin 60 mg/m2 and cyclophosphamide 600 mg/m2) followed by another FNA on day 21 after the first cycle. Total RNA was amplified with T7 Eberwines procedure and labeled cDNA was hybridized onto a 7600-feature glass cDNA microarray.ResultsWe identified candidate gene expression profiles that might distinguish tumors with complete response to chemotherapy from tumors that do not respond, and found that the number of genes that change after one cycle of chemotherapy was 10 times greater in the responding group than in the non-responding group.ConclusionThis study supports the suitability of FNA-derived cDNA microarray expression profiling of breast cancers as a comprehensive genomic approach for studying the mechanisms of drug resistance. Our findings also demonstrate the potential of monitoring post-chemotherapy changes in expression profiles as a measure of pharmacodynamic effect and suggests that these approaches might yield useful results when validated by larger studies.

A pilot trial to evaluate the acute toxicity and feasibility of tamoxifen for prevention of breast cancer

Epidemiological and experimental evidence indicates that oestrogens are involved in the carcinogenic promotion of human breast cancer. We have undertaken a pilot trial of tamoxifen, an anti-oestrogen, compared to placebo given to 200 women at a high risk of developing breast cancer. The results of this trial show that acute toxicity is low and that accrual and compliance are satisfactory. Furthermore, biochemical monitoring of lipids and clotting factors indicate that tamoxifen may reduce the risk of cardiovascular deaths. At this stage no untoward long-term risks have been identified, and it is therefore proposed that a large multicentre trial should be started.

Selective oestrogen receptor modulators in prevention of breast cancer: an updated meta-analysis of individual participant data

Summary 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. Our primary endpoint was incidence of all breast cancer (including ductal carcinoma in situ) during a 10 year follow-up period. Analysis was by intention to treat. Results We analysed data for 83 399 women with 306 617 women-years of follow-up. Median follow-up was 65 months (IQR 54–93). Overall, we noted a 38% reduction (hazard ratio [HR] 0·62, 95% CI 0·56–0·69) in breast cancer incidence, and 42 women would need to be treated to prevent one breast cancer event in the first 10 years of follow-up. The reduction was larger in the first 5 years of follow-up than in years 5–10 (42%, HR 0·58, 0·51–0·66; p<0·0001 vs 25%, 0·75, 0·61–0·93; p=0·007), but we noted no heterogeneity between time periods. Thromboembolic events were significantly increased with all SERMs (odds ratio 1·73, 95% CI 1·47–2·05; p<0·0001). We recorded a significant reduction of 34% in vertebral fractures (0·66, 0·59–0·73), but only a small effect for non-vertebral fractures (0·93, 0·87–0·99). Interpretation For all SERMs, incidence of invasive oestrogen (ER)-positive breast cancer was reduced both during treatment and for at least 5 years after completion. Similar to other preventive interventions, careful consideration of risks and benefits is needed to identify women who are most likely to benefit from these drugs. Funding Cancer Research UK.

Clodronate Decreases the Frequency of Skeletal Metastases in Women with Breast Cancer

The aims of this study were to determine the effects of the bisphosphonate, clodronate, on the incidence of skeletal metastases and associated morbidity in women with advanced breast cancer. 133 women with recurrent breast cancer, but no evidence of skeletal metastases, were randomly allocated to receive clodronate 1600 mg daily by mouth or an identical placebo for 3 years under double-blind conditions at two clinical oncology centers in the UK and Canada. Main outcome measures included the occurrence of skeletal metastases, as judged by sequential bone scans and radiographs, and the morbidity associated with skeletal metastases comprising the incidence of hypercalcemia, vertebral, and nonvertebral fractures, and bone pain assessed by the requirements for skeletal radiotherapy. The number of patients developing skeletal metastases was lower in clodronate-treated patients than with placebo (15 vs. 19), but was not significantly different. The number of skeletal metastases was significantly lower with clodronate treatment than with placebo (32 vs. 63; p < 0.005). The complications of skeletal disease were fewer by 26% in clodronate-treated patients compared to controls (p < 0.01). Compared to placebo, significant effects in favor of clodronate were observed for vertebral deformities (29%) and nonvertebral fractures (75%), but the event frequency of each was low. There was a small (22%) but nonsignificant treatment effect on the requirements for radiotherapy and hypercalcemia (39%). There was no effect of clodronate on survival. We conclude that clodronate by mouth significantly decreases the number and complications of skeletal metastases in women with advanced breast cancer.

Reduction in bone relapse and improved survival with oral clodronate for adjuvant treatment of operable breast cancer [ISRCTN83688026]

IntroductionExperimental and clinical data show that the oral bisphosphonate clodronate (Bonefos®) can inhibit tumor-induced osteoclastic bone resorption. This randomized, double-blind, placebo-controlled, multicenter trial was designed to determine if the addition of oral clodronate to standard treatment for primary operable breast cancer could reduce the subsequent occurrence of bone metastases and thereby improve overall survival.Methods1,069 patients with primary operable stage I-III breast cancer were randomized to receive oral clodronate (1,600 mg/day) or placebo for 2 years, in conjunction with standard treatment for primary breast cancer including surgery, radiotherapy, adjuvant chemotherapy, and/or tamoxifen. All patients were assessed for bone metastases at two and five years and additionally when clinically indicated. Survival status was determined as of the close of the study on 30 June 2000 with a median follow up of 5.6 years. The treatment arms were compared using the unstratified log-rank test. Hazard ratios (HRs) with 95% confidence intervals were calculated.ResultsOral clodronate significantly reduced the risk of bone metastases in all patients over the 5 year study period (51 patients versus 73 patients with placebo; HR = 0.692, P = 0.043); the difference was also statistically significant over the 2 year medication period (19 patients versus 35 patients with placebo; HR = 0.546, P = 0.031). These differences were most pronounced in patients with stage II/III disease (39 patients versus 64 patients with placebo, HR = 0.592, P = 0.009 over 5 years; 16 patients versus 32 patients with placebo, HR= 0.496, P = 0.020 over 2 years). Survival data also favoured the clodronate arm (HR for all patients = 0.768, P = 0.048; HR for stage II/III disease = 0.743, P = 0.041), although this was not significant due to multiple analyses. Oral clodronate was well tolerated, with mild-to-moderate diarrhoea being the most frequently reported adverse event.ConclusionThese results confirm that oral clodronate will significantly improve the 5 year bone relapse free survival when used as a supplementary adjuvant treatment for patients receiving standard treatment for primary operable breast cancer.