Breast Cancer Prevention Trial Research Articles

Inflammatory Marker Changes in a Yearlong Randomized Exercise Intervention Trial among Postmenopausal Women

Chronic low-grade inflammation is a possible risk factor for cancer that may be modifiable with long-term exercise. Very few randomized controlled trials (RCT) have studied the isolated effects of exercise on low-grade inflammation exclusively in postmenopausal women. The Alberta Physical Activity and Breast Cancer Prevention Trial, a 2-armed RCT in healthy postmenopausal women, examined how 1 year of moderate to vigorous aerobic exercise, compared with usual inactivity, influenced circulating inflammatory markers. Baseline, 6-month, and 12-month serum was analyzed by direct chemiluminescent immunoassays to measure high sensitivity C-reactive protein (CRP) and ELISAs to measure interleukin 6 (IL-6) and TNF-α. Intention to treat analyses were conducted with linear mixed models. Statistically significant differences in CRP were observed over 12 months for exercisers versus controls (treatment effect ratio = 0.87, 95% CI = 0.79-0.96, P = 0.005), but not in IL-6 or TNF-α. A statistically significant trend (P(trend) = 0.021) of decreasing CRP with increasing exercise adherence and stronger intervention effects on CRP in women with higher baseline physical fitness (P(heterogeneity) = 0.040) was found. The intervention effect on CRP became statistically nonsignificant with adjustment for dietary fiber intake change and seemed to be mediated by fat loss. Low-grade inflammation may be lowered with exercise, but confounding by dietary intake occurred and should be considered in future studies. Further trials are needed to corroborate our findings about the optimal dose of exercise required to lower CRP levels and effect modification of CRP changes by levels of body fatness and fitness.

P3-11-07: Mammary Gland Biopsy To Examine Surrogate Endpoint Biomarkers of Preventive Agent Efficacy.

Abstract Phase II breast cancer prevention trials examine agent activity by sampling and imaging the breast through core needle biopsy, fine needle aspiration, or imaging (e.g., mammography). The biomarker endpoints in normal or at risk breast tissue employed with biopsies or fine needle aspirates (e.g., Ki67 or apoptosis) have often not been formally validated relative to a tumor endpoint. In this study, we have attempted to examine these endpoints in a preclinical model for which we have final tumor data. In the methylnitrosourea (MNU)-induced rat mammary cancer model, estrogen receptor positive cancers develop that are histologically similar to a large majority of human tumors. Here we present a protocol for correlating surrogate endpoint biomarkers and agent efficacy in the same animal. Biopsy samples are taken of the normal mammary gland after MNU treatment, and a week later the animals are started on the preventive agent. After 2 weeks, a second biopsy is taken and the animals are followed for tumor development. To test the protocol, we examined surrogate endpoints of tamoxifen efficacy at human equivalent dosages (5mg/d and 20mg/d). Both doses of tamoxifen prevented the development of tumors in the MNU-treated rats. The pre/post biopsy analysis revealed a statistically significant reduction in Ki-67 consistent with the clinical trial data. Additional biomarkers of apoptosis and the chromosome condensation pathway will be presented. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-11-07.

Uptake of a randomized breast cancer prevention trial comparing letrozole to placebo in BRCA1/2 mutations carriers: the LIBER trial

Women with germline BRCA1 or BRCA2 (BRCA1/2) mutations are considered as an extreme risk population for developing breast cancer. Prophylactic mastectomy provides a valid option to reduce such risk, impacting however, the quality of life. Medical prevention by aromatase inhibitor that has also recently shown to have preventive effect may thus be considered as an alternative. LIBER is an ongoing double-blind, randomized phase III trial to evaluate the efficacy of 5-year letrozole versus placebo to decrease breast cancer incidence in post-menopausal BRCA1/2 mutation carriers (NCT00673335). We present data on the uptake of this trial. We compared characteristics of women in the LIBER trial (n=113) to those of women enrolled in the prospective ongoing national GENEPSO cohort (n=1,505). Uptake was evaluated through a survey sent to all active centres, with responses obtained from 17 to the 20 (85%) centres. According to the characteristics of the women enrolled in the GENEPSO cohort and the survey, approximately one-third of BRCA1/2 mutation carriers were eligible for the trial. Five hundred and thirty-four women eligible from chart review have been informed by mail about the prevention trial and were invited to an oral information by participating centres. Forty-four percentage of them came to the dedicated medical visit. Uptake of drug prevention trial was 32% among women informed orally and 15% of all the eligible women. The main reasons of refusal were: potential side effects, probability to receive the placebo and lack of support from their physicians. Additionally, we noticed that prior prophylactic oophorectomy and previous unilateral breast cancer were more frequent in women enrolled in the LIBER trial than in the French cohort (93% vs. 60% and 50% vs. 39%, respectively). Based on an overall 15% uptake among all eligible subjects, greater and wider information of the trial should be offered to women with BRCA1/2 mutation to improve recruitment. Women with previous unilateral breast cancer or prior prophylactic oophorectomy are more likely to enter a medical prevention trial.

Predictors of Adherence to Supervised and Unsupervised Exercise in the Alberta Physical Activity and Breast Cancer Prevention Trial

Few studies have examined the predictors of adherence separately for supervised and unsupervised exercise or in postmenopausal women over an extended time period. Here, we report the predictors of exercise adherence in the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial. The ALPHA trial randomized 160 postmenopausal women in Calgary and Edmonton, Canada to an exercise intervention that consisted of an average of 200 min/wk of supervised (123 minutes) and unsupervised (77 minutes) exercise over a 1-year period. Baseline data were collected on demographic, health-related fitness, quality of life, and motivational variables from the theory of planned behavior. Participants completed an average of 95% of their supervised exercise and 79% of their unsupervised exercise. In multivariate analyses, 8.1% (P=.001) of the variance was explained for supervised exercise by being from Edmonton (β=0.22; P=.004) and older (β=0.15; P=.050). For unsupervised exercise, 21.1% (P<.001) of the variance was explained by being from Calgary (β=-0.39; P<.001), having a family history of breast cancer (β=0.21; P=.003), and having higher vitality (β=0.19; P=.011). Predictors of adherence may differ for supervised and unsupervised exercise, moreover, predicting adherence to supervised exercise may be particularly difficult in well-controlled efficacy trials.

Cigarette Smoking, Obesity, Physical Activity, and Alcohol Use As Predictors of Chemoprevention Adherence in the National Surgical Adjuvant Breast and Bowel Project P-1 Breast Cancer Prevention Trial

The double-blind, prospective, National Surgical Adjuvant Breast and Bowel Project (NSABP) Breast Cancer Prevention Trial (BCPT) showed a 50% reduction in the risk of breast cancer for tamoxifen versus placebo, yet many women at risk of breast cancer do not adhere to the 5-year course. This first report of the rich BCPT drug adherence data examines predictors of adherence. Between June, 1992 and September, 1997 13,338 women at high risk of breast cancer were randomly assigned to 20 mg/d tamoxifen versus placebo; we analyzed the 11,064 enrolled more than 3 years before trial unblinding. Primary endpoint was full drug adherence (100% of assigned pills per staff report, excluding protocol-required discontinuation) at 1 and 36 months; secondary was adequate adherence (76%-100%). Protocol-specified multivariable logistic regression tested lifestyle factors, controlling for demographic and medical predictors. About 13% were current smokers; 60% were overweight/obese; 46% had moderate/heavy physical activity; 21%, 66%, 13% drank 0, 0-1, 1+ drinks per day, respectively; 91% were adequately adherent at 1 month; and 79% were at 3 years. Alcohol use was associated with reduced full adherence at 1 month (P = 0.016; OR = 0.79 1+ vs. 0), as was college education (P <0.001; OR = 0.78 vs. high school); age (P < 0.001; OR = 1.4 age 60+) and per capita household annual income (P < 0.001; OR = 1.2 per $30,000) with increased adherence. Current smoking (P = 0.003; OR = 0.75), age (P = 0.024, OR = 1.1), college education (P = 0.037; OR = 1.4), tamoxifen assignment (P = 0.031; OR = 0.84), and breast cancer risk (P <.001; OR = 1.5 high vs. low) predicted adequate adherence at 36 months. There were no significant associations with obesity or physical activity. Alcohol use and smoking might indicate a need for greater adherence support.

Abstract B9: Community strategies for investigating the biology of breast and cervical cancer initiation in African-American women

Abstract Background: African-American women have the highest overall cancer death rate from breast and cervical cancer and shortest survival of any racial and ethnic group in the United States. These disparities are heightened in the Southern United States. For example, the US breast cancer death rate is 23.0 (per 100,000) for Caucasian women, as compared to 34.3 for African-American women. The North Carolina breast cancer death rate is 27.2 for Caucasian women and 38.0 for African Americans; and in our study area, Durham County, the breast cancer death rate is 27.5 for Caucasians and 42.0 for African-Americans. The causes of these inequalities are complex and interrelated, but arise, at least in part, from disparities in income, education, nutrition, and access to healthcare. For complex historical reasons, African-Americans have had mixed experiences in accessing care and in the quality of care they receive. In addition, distrust has arisen within the African-American community regarding the intents and purposes of health care researchers. Cutting edge breast imaging technology, prevention, and early detection trials exist at academic that could potentially improve early diagnosis and increase our chance of understanding the complex relationship between disparities, genetics, diet, and the environment in promoting breast cancer. Lack of access, mistrust, and community barriers all play a key role in preventing young African-American women from benefiting from state-of-the-art breast imaging and new strategies for early detection of breast and cervical cancer. Methods and Results: To address the unacceptably high death rate among young African-American women from breast and cervical cancer, we have used a multi-disciplinary intervention that includes: 1) community Navigators, 2) access to breast and cervical cancer prevention and early detection services through free community clinics, 3) community partnered breast and cervical cancer prevention trials, and 4) opportunities for mentorship and career development. As a result, we have been able to improve access to early detection strategies in a community based setting and have provided mentorship for 27 young Minority scholars to enter medical school and graduate programs. Our community based breast MRI trial for underserved women has performed over 600 breast MRI since 2004. Over 50% of these women entered in this trial are Women-of-Color. Conclusion: A community based strategy can be highly successful for improving early detection of breast and cervical cancer but only if there is community participation during the initiation of clinical trials and joint community-academic mentorship of young Minority Scholars. Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B9.

Evaluation of the psychometric properties of the BCPT Symptom Checklist with a sample of breast cancer patients before and after adjuvant therapy

The purpose of this analysis was to provide psychometric information related to the Breast Cancer Prevention Trial (BCPT) Symptom Checklist in women with breast cancer prior to the initiation of adjuvant therapy and 6 months post-initiation of therapy. This investigation was a secondary analysis of baseline data from the Anastrozole Use in Menopausal Women (AIM) Study (R01 CA 107408). The data used in this study were obtained from women diagnosed with Stage I, II, and IIIa breast cancer and who received adjuvant therapy that included chemotherapy alone, anastrozole alone, and chemotherapy plus anastrozole. Data were examined before adjuvant therapy (n=278), and at 6 months post-adjuvant therapy (n=195). Construct validity was examined through exploratory and confirmatory factor analysis (CFA), and the internal consistency of each resulting subscale was computed. Discriminant validity evidence was obtained by correlating BCPT subscales with subscales from the MOS SF-36. A seven-factor structure was extracted from the 42 items at baseline; an eight-factor structure was found using 6-month data. CFA was performed to compare the baseline and 6-month models as well as an eight-factor model recommended by Cella et al. Findings revealed that the two eight-factor models best represented the data. Low negative correlations with the subscales of the MOS SF-36 provided discriminant validity evidence. This analysis provides evidence for the reliability, discriminant validity, and factor structure of the BCPT Symptom Checklist. Further testing of this instrument is needed to confirm the factor structure of this measure.

Update on Phase I/II Breast Cancer Prevention Trials

The greatest success in breast cancer prevention has been with two agents, tamoxifen and raloxifene, both of which are approved by the US Food and Drug Administration (FDA) for the risk reduction of invasive breast cancer in high-risk women. However, these agents are only effective in preventing a certain percentage of estrogen receptor–positive disease. New agents are needed to prevent invasive breast cancer in a broader population of women. Phase I/II clinical trials are conducted with the intent of investigating agent efficacy via surrogate endpoint biomarkers. They also allow us to refine the population that may benefit from a given intervention. In this article, we review the important components of early phase trials including study design, cohort, surrogate endpoint biomarkers, and the challenges of recruiting to prevention trials. We discuss some early-phase trials for which results have recently been reported at meetings or through publications, as well as those trials that have recently been opened.

Tamoxifen downregulation of miR-451 increases 14-3-3ζ and promotes breast cancer cell survival and endocrine resistance

Many estrogen receptor-positive breast cancers respond well initially to endocrine therapies, but often develop resistance during treatment with selective estrogen receptor modulators (SERMs) such as tamoxifen. We have reported that the 14-3-3 family member and conserved protein, 14-3-3ζ, is up-regulated by tamoxifen and that high expression correlated with an early time to disease recurrence. However, the mechanism by which tamoxifen up-regulates 14-3-3ζ and may promote the development of endocrine resistance is not known. Our findings herein reveal that the tamoxifen up-regulation of 14-3-3ζ results from its ability to rapidly down-regulate miR-451 that specifically targets 14-3-3ζ. The levels of 14-3-3ζ and miR-451 were inversely correlated, with 14-3-3ζ being elevated and miR-451 being at a greatly reduced level in tamoxifen-resistant breast cancer cells. Of note, down-regulation of miR-451 was selectively elicited by tamoxifen but not by other SERMs such as raloxifene or ICI182,780 (Fulvestrant). Increasing the level of miR-451 by overexpression, which decreased 14-3-3ζ, suppressed cell proliferation and colony formation, markedly reduced activation of HER2, EGFR, and MAPK signaling, increased apoptosis, and importantly, restored the growth inhibitory effectiveness of SERMs in endocrine-resistant cells. Opposite effects were elicited by miR-451 knock-down. Thus, we identify tamoxifen down-regulation of miR-451, and consequent elevation of the key survival factor 14-3-3ζ, as a mechanistic basis of tamoxifen-associated development of endocrine resistance. These findings suggest that therapeutic approaches to increase expression of this tumor suppressor-like microRNA should be considered to down-regulate 14-3-3ζ and enhance the effectiveness of endocrine therapies. Furthermore, the selective ability of the SERM tamoxifen but not raloxifene to regulate miR-451 and 14-3-3ζ may assist in understanding differences in their activities, as seen in the STAR breast cancer prevention trial and in other clinical trials.

Cigarette smoking, fitness, and alcohol use as predictors of cancer outcomes among women in the National Surgical Adjuvant Breast and Bowel Project (NSABP) Breast Cancer Prevention Trial (BCPT).

1505 Background: The double-blind, prospective, BCPT demonstrated a 50% reduction in the risk of breast cancer for tamoxifen (T) v placebo (P). We present the risk of cancer at the most common sites, based on the participants’ baseline self-reported cigarette smoking, alcohol use, and leisure-time physical activity. Methods: 13,338 women at high risk of bc. Were randomly assigned 6/92-9/97 to 20 mg/day T v P; we analyzed the 11,064 enrolled more than 3 years (yrs) before the trial unblinding 3/98. Endpoints invasive cancer of the breast (ibc), endometrium (ec), lung (lc), and colon (cc) were analyzed with Cox proportional hazards regression. Covariates were baseline estimated breast cancer risk, treatment assignment, race, age, and co-morbidities. Hazards ratios (HR) are given with 95% bracketed confidence intervals. Results: At baseline, 45.7% had moderate/heavy physical activity. 20.5%, 65.8%, 13.3% drank 0, 0-1, 1+ alcoholic drinks/day. 12.8% were current smokers. At median 8.7 years potential follow-u...

Benefit/Risk Assessment for Breast Cancer Chemoprevention With Raloxifene or Tamoxifen for Women Age 50 Years or Older

The Study of Tamoxifen and Raloxifene (STAR) demonstrated that raloxifene was as effective as tamoxifen in reducing the risk of invasive breast cancer (IBC) in postmenopausal women and had lower risks of thromboembolic events, endometrial cancer, and cataracts but had a nonstatistically significant higher risk of noninvasive breast cancer. There is a need to summarize the risks and benefits of these agents. Baseline incidence rates of IBC and other health outcomes, absent raloxifene and tamoxifen, were estimated from breast cancer chemoprevention trials; the Surveillance, Epidemiology and End Results Program; and the Women's Health Initiative. Effects of raloxifene and tamoxifen were estimated from STAR and the Breast Cancer Prevention Trial. We assigned weights to health outcomes to calculate the net benefit from raloxifene compared with placebo and tamoxifen compared with placebo. Risks and benefits of treatment with raloxifene or tamoxifen depend on age, race, breast cancer risk, and history of hysterectomy. Over a 5-year period, postmenopausal women with an intact uterus had a better benefit/risk index for raloxifene than for tamoxifen. For postmenopausal women without a uterus, the benefit/risk ratio was similar. The benefits and risks of raloxifene and tamoxifen are described in tables that can help identify groups of women for whom the benefits outweigh the risks. We developed a benefit/risk index to quantify benefits from chemoprevention with tamoxifen or raloxifene. This index can complement clinical evaluation in deciding whether to initiate chemoprevention and in comparing the benefits and risks of raloxifene versus tamoxifen.

Abstract 4727: Breast cancer prevention and selective estrogen response modulators (SERMs): Pharmacogenomics and differential estrogen and SERM regulation of BRCA1 and BRCA2 expression

Abstract Introduction: The NSABP P-1 and P-2 breast cancer prevention trials have demonstrated that the SERMs tamoxifen and raloxifene can reduce the risk of breast cancer in high risk women. Methods: We performed a nested matched case-control GWAS utilizing DNA from participants enrolled in P-1 and P-2. 592 participants developed invasive breast cancer or ductal carcinoma in situ, and were matched with 1171 controls who did not. Genome-wide genotyping with the Illumina 610-Quad chip and CYP2D6 genotyping for pertinent alleles were performed. Functional genomic studies involved the use of cultured cells, with siRNA knockdown, followed by qRT-PCR and Western blot analyses. Results: Eleven SNPs with p-values &amp;lt; 3E-05 were identified. Twenty one additional SNPs with p &amp;lt; 4E-05 were identified by imputation around the genotyped SNPs on chromosomes (Chrs) 4, 8, 9, 13, 16 and 22, which were then genotyped with the Invader platform. Initial functional genomic studies focused on 6 SNPs on Chr16 (p-values 1.81-9.55E-06), all of which were in ZNF423, a gene encoding a putative zinc-finger protein. The Chr16 minor variant SNP sequences had less risk than the common variant (OR=0.7). Our functional studies showed that incubation of Hs578T cells stably transfected with estrogen receptor (ER) α with 0.1 nM estradiol (E2) induced expression of ZNF423, BRCA1/2 for WT but not variant SNP sequences. There was also a striking difference between E2-induced ZNF423, BRCA1/2 expression for variant and WT SNPs in lymphoblastoid cell lines (LCLs) stably transfected with ERα, with only WT showing induction. ChIP assay showed that ZNF423 could bind to the 5’-flanking region of BRCA1, and reporter gene assays showed that ZNF423 could regulate BRCA1/2 transcription. In LCLs stably transfected with ERα and genotyped for ZNF423 SNPs, estrogen-dependent expression of all 3 genes occurred only in the presence of the WT, but not variant ZNF423 SNP sequences. Blockade of ERα with 4-OH tamoxifen prevented induction of expression in cells with WT sequences, but resulted in gene dose-dependent increases in BRCA1/2 expression in cells with variant SNP sequences-suggested that the minor variant has a “protective” effect during clinical SERM therapy and verified by ChIP assays. Conclusions: The SNPs in ZNF423 identified during GWAS were associated with differential E2-dependent induction of ZNF423, BRCA1 and BRCA2-implying that ZNF423 is “upstream” for the estrogen-dependent induction of BRCA1/2 expression. However, LCLs with variant SNP sequences showed greatly enhanced expression of ZNF423, BRCA1/2 during 4-OH tamoxifen exposure, while cells with WT sequences did not. These results may reveal a novel mechanism for SERM-dependent regulation of BRCA1/2 expression and may have implications for patient selection for SERM therapy. Funded by U10-CA37377, U10-CA69974 and U14-GM61388. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4727. doi:10.1158/1538-7445.AM2011-4727

Abstract 939: Mechanistic basis of tamoxifen-associated development of endocrine resistance in breast cancer

Abstract Many estrogen receptor-positive breast cancers respond well initially to endocrine therapies, but often develop resistance during treatment with SERMs such as tamoxifen. We have reported that the 14-3-3 family member and conserved protein, 14-3-3ζ, is up-regulated by tamoxifen and that high expression correlated with an early time to disease recurrence. However, the mechanism by which tamoxifen up-regulates 14-3-3ζ and may promote the development of endocrine resistance is not known. Our findings reveal that the tamoxifen up-regulation of 14-3-3ζ results from its ability to rapidly down-regulate a microRNA that specifically targets 14-3-3ζ. The levels of 14-3-3ζ and this microRNA were always inversely correlated, with 14-3-3ζ being elevated and the microRNA being at a low down-regulated level in tamoxifen-resistant breast cancer cells. Of note, down-regulation of the microRNA was selectively elicited by tamoxifen but not by other SERMs such as raloxifene or by the estrogen receptor down-regulator ICI182,780 (Fulvestrant). Reducing the cellular level of 14-3-3ζ by either antagomiR blockade of the tamoxifen suppression of the microRNA or by elevation of the intracellular level of the microRNA by over-expression resulted in decreased cell proliferation and colony formation, increased apoptosis, and very importantly, restoration of the growth inhibitory effectiveness of SERMs in endocrine-resistant breast cancer cells. Restoration of responsiveness to endocrine therapy was also accompanied by markedly reduced activation of HER2, EGFR, and MAPK signaling, key components in endocrine resistance. Thus, we identify tamoxifen down-regulation of a microRNA, and consequent elevation of the key survival factor 14-3-3ζ, as a mechanistic basis of tamoxifen-associated development of endocrine resistance. These findings suggest that therapeutic approaches that increase expression of this microRNA should be considered to down-regulate 14-3-3ζ and enhance the effectiveness of endocrine therapies. Furthermore, the observed differential effects of the two SERMs, tamoxifen and raloxifene, in regulation of this microRNA and 14-3-3ζ, may assist in understanding differences in the activities of these SERMs, as seen in the STAR breast cancer prevention trial and in other clinical trials. (Supported by a grant from The Breast Cancer Foundation to BSK and a postdoctoral fellowship from the Department of Defense (W81XWH-09-1-0398) to AB.) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 939. doi:10.1158/1538-7445.AM2011-939

Abstract 3675: Effects of cytochrome P450 2D6 polymorphisms on tamoxifen metabolism in a pooled analysis of breast cancer prevention trials designed to define the minimal active dose of the drug

Abstract Background Tamoxifen is the most widely used drug for the prevention and treatment of hormone-receptor positive breast cancer (BC). Nevertheless, its clinical effectiveness varies among individuals. Tamoxifen is extensively metabolized by cytochrome P450 (CYP) enzymes, and recent in vivo studies have shown that women with genetically impaired CYP2D6 have reduced production of endoxifen, the main active metabolite. This impairment has been linked to a higher risk of breast cancer recurrence. Despite these observations, the contribution of endoxifen to the overall drug effectiveness of tamoxifen remains uncertain. Methods and results This study presents a pooled analysis of four chemoprevention trials assessing three different low dose tamoxifen schedules: 1mg/day (n=52), 10 mg/week (n=152) and 5 mg/day (n=158). Each participant had signed an informed consent. Genomic DNA was extracted from whole blood by the QIAamp DNA Blood Kit (Qiagen, Valencia, CA, USA), and the CYP2D6 polymorphisms analyzed by the use of the INFINITI CYP450 2D6T Assay (AutoGenomics, Carlsbad, CA, USA). The following alleles were identified: Full enzyme activity: *1, *2; reduced activity: *9, *41 *29; no activity: *3, *4, *5, *6. A total of 336 out of the 362 study participants were genotyped. Circulating concentrations of tamoxifen and its metabolites were determined on cryo-conserved (−80°C) serum samples collected at different treatment intervals according to study design. The women were defined as extensive metabolizers (EM) if they had 2 fully active alleles; intermediate (IM) if they carried reduced alleles or one non-functional allele, while poor metabolizers (PM) carried two non-functional alleles. We found the following phenotype frequencies: 146/336 (43%) EM, 171/336 (51%) IM, 19/336 (6%) PM. When analyzing the effects of phenotypes on serum concentrations of tamoxifen and its metabolites we found a statistically significant effect of phenotype on tamoxifen and metabolites. EM had lower levels of tamoxifen (8,6 ng/mL; P&amp;lt;0.02) and its main metabolite N-desmethyltamoxifen (Ndestam: 17,4 ng/mL; P&amp;lt;0.0001) as compared to impaired metabolizers (IM+PM), who had median tamoxifen levels of 15 ng/mL and Ndestam of 30 ng/mL. No difference was observed on endoxifen levels, possibly due to the low dose schedules. Nevertheless, the increase in Ndestam concentrations in the group of impaired metabolizers is an important indirect effect of lower CYP2D6 activity, showing an accumulation of its main substrate. The relationship between CYP2D6 phenotype and tamoxifen pharmacokinetics will be extended, including women taking tamoxifen at 20mg/day for one year. Conclusions These findings support the relevance of pharmacogenetics in tailoring tamoxifen treatment in the setting of breast cancer prevention. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3675. doi:10.1158/1538-7445.AM2011-3675

Changes in insulin resistance indicators, IGFs, and adipokines in a year-long trial of aerobic exercise in postmenopausal women

Physical activity is a known modifiable lifestyle means for reducing postmenopausal breast cancer risk, but the biologic mechanisms are not well understood. Metabolic factors may be involved. In this study, we aimed to determine the effects of exercise on insulin resistance (IR) indicators, IGF1, and adipokines in postmenopausal women. The Alberta Physical Activity and Breast Cancer Prevention Trial was a two-armed randomized controlled trial in postmenopausal, inactive, cancer-free women. A year-long aerobic exercise intervention of 225 min/week (n=160) was compared with a control group asked to maintain usual activity levels (n=160). Baseline, 6- and 12-month serum levels of insulin, glucose, IGF1, IGF-binding protein 3 (IGFBP3), adiponectin, and leptin were assayed, and after data collection, homeostasis model assessment of IR (HOMA-IR) scores were calculated. Intention-to-treat analyses were performed using linear mixed models. The treatment effect ratio (TER) of exercisers to controls was calculated. Data were available on 308 (96.3%) women at 6 months and 310 (96.9%) women at 12 months. Across the study period, statistically significant reductions in insulin (TER=0.87, 95% confidence interval (95% CI)=0.81–0.93), HOMA-IR (TER=0.86, 95% CI=0.80–0.93), and leptin (TER=0.82, 95% CI=0.78–0.87), and an increase in the adiponectin/leptin ratio (TER=1.21, 95% CI=1.13–1.28) were observed in the exercise group compared with the control group. No significant differences were observed for glucose, IGF1, IGFBP3, adiponectin or the IGF1/IGFBP3 ratio. Previously inactive postmenopausal women who engaged in a moderate-to-vigorous intensity exercise program experienced changes in insulin, HOMA-IR, leptin, and adiponectin/leptin that might decrease the risk for postmenopausal breast cancer.

Long-Term Follow-Up of Women in Trials of Adjuvant Therapy for Breast Cancer: Is It Still Important?

Long-Term Follow-Up of Women in Trials of Adjuvant Therapy for Breast Cancer: Is It Still Important?

Do selective estrogen receptor modulators treat cervical precancer and cancer? Time to pool data from relevant trials

Based on the nearly absolute etiologic link between carcinogenic human papillomavirus (HPV) and cervical cancer, two new approaches for the prevention of cervical cancer have emerged: (1) HPV vaccination for primary HPV prevention in younger women and (2) carcinogenic HPV detection for secondary prevention via identifying and treating cervical precancer and early cancers. Both have demonstrated high degrees of efficacy with maximum effectiveness guided by an understanding of the causal model and application of these technologies in an age appropriate manner.1 Despite the advent of these promising prevention tools, there is a real need to develop nonsurgical methods for treating cervical precancerous lesions and even early cancer for three reasons. First, current HPV vaccines are prophylactic and do not treat pre-existing HPV infections.1 Second, surgical excision of screen-detected precancerous lesions, while a highly efficacious (90–95%) treatment1 increases the risk of preterm delivery and infant morbidity and mortality.2 Third, most women who screen positive by a Pap and/or HPV do not have clinically actionable disease, yet these women are at risk of cervical precancer and cancer in the future and must be followed up intensively. In addition, in the low-resource settings, surgical methods are not commonly available and cryotherapy, while moderately efficacious when its use is limited to smaller lesions, causes significant watery discharge and requires sexual abstinence for several weeks to permit healing of treated epithelium. Despite the knowledge that HPV infection is the obligate cause of cervical cancer, targeted immunological approaches for therapy such as therapeutic vaccines have been unsuccessful.3 Chung and Lambert4 present a novel approach of using estrogen receptor antagonists (selective estrogen receptor modulators or SERMs) to treat cervical precancer and cancer. As noted by the authors, there are strongly supportive laboratory5 and epidemiological data6, 7 that estrogen plays contributing role in cervical carcinogenesis. In this study, Chung and Lambert4 successfully treated 7 E6/E7 transgenic mice that spontaneously manifested cervical cancer with Raloxifene, an estrogen receptor antagonist that reduces the risk of breast cancer. To investigate whether Raloxifene might reduce the incidence of cervical cancer and its immediate precursor, carcinoma in situ (CIS), previously unpublished data on these outcomes from two randomized clinical trials to evaluate two SERMs, tamoxifen and raloxifene, for breast cancer risk reduction were analyzed. The NSABP (National Surgical Adjuvant Breast and Bowel Project), an NCI funded Cooperative Group, has designed and conducted the two large breast cancer prevention trials, Breast Cancer Prevention Trial P-1 (BCPT-P1)8 and Study of Tamoxifen vs. Raloxifene (STAR).9 While both tamoxifen and raloxifene are estrogen receptor antagonists in breast tissue, raloxifene is an estrogen receptor antagonist whereas tamoxifen is an agonist in the human reproductive tract (e.g., Tamoxifen increases the risk of endometrial cancer while raloxifene does not.).4, 10, 11 However, as shown in the Table 1, despite small numbers, there was no evidence that long-term raloxifene use reduces, or long-term tamoxifen use increases, the risk of cervical CIS and cancer (n.b., results were combined because SERMS were reported to treat both in the mouse models, and CIS has a high risk of invading if left untreated12) (BCPT P-1: Placebo vs. Tamoxifen, p = 1.0, two-sided Fisher's exact; STAR: Tamoxifen vs. Raloxifene, p = 1.0, two-sided Fisher's exact). This post-hoc analysis was limited by small numbers. Data from other clinical trials of SERMs13, 14 should be pooled to examine the impact of SERMs on outcomes of cervical precancer and cancer. Until evidence is forthcoming on the positive effects of SERMs on cervical precancer and cancer in humans, extreme caution in interpreting data from mouse models is warranted. Despite the probable role of estrogens in cervical carcinogenesis, the protective effects of SERMs against cervical cancer cannot be inferred based on mouse models. Importantly, the therapeutic effectiveness of SERMs would need to be exceeding high to be acceptable, given the efficacy of current methods of treatment for cervical intraepithelial neoplasia15 and early cervical cancer.16 Dr. Castle acknowledges Dr. Joseph Costantino (University of Pittsburgh, Pittsburgh, PA, USA) for providing data from Breast Cancer Prevention Trial P-1 (BCPT-P1) and the Study of Tamoxifen vs. Raloxifene (STAR). Dr. Castle was supported by the Intramural Research Program of the NIH, National Cancer Institute and he reports no conflicts of interest. Yours sincerely, Philip E. Castle

Abstract P1-07-02: Acceptability of Breast Cancer Medical Prevention by Letrozole in Post-Menopausal Women with a BRCA1/2 Mutation in the LIBER Trial

Abstract Background: Women carrying a germline BRCA1/2 mutation have a lifetime risk of developing breast cancer of 56 to 80%. Prophylactic bilateral mastectomy provides a valid option to reduce breast cancer incidence, but considerably affects the quality of life. There is therefore an urgent need to evaluate medical preventive alternative. The major breast cancer prevention trials using tamoxifen showed an approximately 50% incidence reduction in high risk women. Adjuvant trials comparing aromatase inhibitors (AI) to tamoxifen revealed a higher preventive efficacy of AI for contra-lateral cancer with fewer thrombo-embolic side effects. Patients and Methods: The French federation of cancer centres (“FNCLCC”) has designed a randomized phase III trial to determine the efficacy of letrozole to prevent breast cancer in postmenopausal BRCA1/2 carriers. The “LIBER” study is a double-blind, letrozole versus placebo study involving 32 centers among with 20 are actives. The study opened for recruitment in march 2008. Results: Here we present data reflecting the acceptability of this preventive trial. Twenty-one centers replied to an inquiry. 690 women were eligible. Out of 485 women informed by letter, 217 (44%) came to consultation and 62 (13%) entered the study. The main concerns of women while considering to enter the trial were: the potential side effects, the probability to receive the placebo and the lack of support from other practitioners. Out of 78 enrolled women, 48 (62%) were BRCA1 mutation carriers, 30 (38%) were BRCA2 mutation carriers, 73 (93%) were oophorectomized, 38 (49%) had a previous unilateral cancer, 40 (52%) did not have cancer. 30 (38%) women were less than 50 years old, and 48 (62%) were 50 or over 50 years old. Discussion: For post-menopausal women bearing a BRCA1/2 genetic predisposition, prevention of breast cancer risk by letrozole could provide a precious alternative when bilateral mastectomy is not retained. Among women who received oral information, the acceptability of this randomized double-blind letrozole versus placebo trial is 28%. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-07-02.

Abstract PL03-04: Exercise, adiposity, and cancer

Abstract PL03-04: Exercise, adiposity, and cancer

A Bayesian Shrinkage Model for Incomplete Longitudinal Binary Data With Application to the Breast Cancer Prevention Trial

We consider inference in randomized longitudinal studies with missing data that is generated by skipped clinic visits and loss to followup. In this setting, it is well known that full data estimands are not identified unless unverified assumptions are imposed. We assume a non-future dependence model for the drop-out mechanism and partial ignorability for the intermittent missingness. We posit an exponential tilt model that links nonidentifiable distributions and distributions identified under partial ignorability. This exponential tilt model is indexed by nonidentified parameters, which are assumed to have an informative prior distribution, elicited from subject-matter experts. Under this model, full data estimands are shown to be expressed as functionals of the distribution of the observed data. To avoid the curse of dimensionality, we model the distribution of the observed data using a Bayesian shrinkage model. In a simulation study, we compare our approach to a fully parametric and a fully saturated model for the distribution of the observed data. Our methodology is motivated by, and applied to, data from the Breast Cancer Prevention Trial.