Outcomes in women with invasive ductal or invasive lobular early stage breast cancer treated with anastrozole or exemestane in CCTG (NCIC CTG) MA.27.

BACKGROUND: Histological subtype, (invasive ductal breast cancer (IDBC)/invasive lobular breast cancer (ILBC)), might be a marker for differential response to endocrine therapy in breast cancer. METHODS: Clinical trial MA.27 compared 5 years of adjuvant anastrozole or exemestane in postmenopausal patients with hormone receptor positive early breast cancer. We evaluated IDBC versus ILBC (based on original pathology reports) as predictor for event-free survival (EFS) and overall survival (OS). RESULTS: A total of 5709 patients (5021 with IDBC and 688 with ILBC) were included (1876 were excluded because of missing or other histological subtype). Median follow-up was 4.1 years. Overall, histological subtype did not influence OS or EFS (HR (hazard ratio) 1.14, 95% confidence interval (CI) [0.79-1.63], P = 0.49 and HR 1.04, 95% CI [0.77-1.41], P = 0.81, respectively). There was no significant difference in OS between treatment with exemestane versus treatment with anastrozole in the IDBC group (HR = 0.92, 95% CI [0.73-1.16], P = 0.46). In the ILBC group, a marginally significant difference in favour of treatment with anastrozole was seen (HR = 1.79, 95% CI [0.98-3.27], P = 0.055). In multivariable analysis a prognostic effect of the interaction between treatment and histological subtype on OS (but not on EFS) was noted, suggesting a better outcome for patients with ILBC on anastrozole (HR 2.1, 95% CI [0.99-4.29], P = 0.05). After stepwise selection in the multivariable model, a marginally significant prognostic effect for the interaction variable (treatment with histological subtype) on OS (but not on EFS) was noted (Ratio of HR 2.1, 95% CI [1.00-4.31], P = 0.05). CONCLUSION: Our data suggest an interaction effect between treatment and histology (P = 0.05) on OS. Here, patients with ILBC cancers had a better OS when treated with anastrozole versus exemestane, whereas no difference was noted for patients with IDBC. CLINICAL TRIAL INFORMATION: NCT00066573.

Impact of baseline BMI and weight change in CCTG adjuvant breast cancer trials.

BACKGROUND: We hypothesized that increased baseline BMI and BMI change would negatively impact clinical outcomes with adjuvant breast cancer systemic therapy. METHODS: Data from chemotherapy trials MA.5 and MA.21; endocrine therapy MA.12, MA.14 and MA.27; and trastuzumab HERA/MA.24 were analyzed. The primary objective was to examine the effect of BMI change on breast cancer-free interval (BCFI) landmarked at 5 years; secondary objectives included BMI changes at 1 and 3 years; BMI changes on disease-specific survival (DSS) and overall survival (OS); and effects of baseline BMI. Stratified analyses included trial therapy and composite trial stratification factors. RESULTS: In pre-/peri-/early post-menopausal chemotherapy trials (N = 2793), baseline BMI did not impact any endpoint and increased BMI from baseline did not significantly affect BCFI (P = 0.85) after 5 years although it was associated with worse BCFI (P = 0.03) and DSS (P = 0.07) after 1 year. BMI increase by 3 and 5 years was associated with better DSS (P = 0.01; 0.01) and OS (P = 0.003; 0.05). In pre-menopausal endocrine therapy trial MA.12 (N = 672), patients with higher baseline BMI had worse BCFI (P = 0.02) after 1 year, worse DSS (P = 0.05; 0.004) after 1 and 5 years and worse OS (P = 0.01) after 5 years. Increased BMI did not impact BCFI (P = 0.90) after 5 years, although it was associated with worse BCFI (P = 0.01) after 1 year. In post-menopausal endocrine therapy trials MA.14 and MA.27 (N = 8236), baseline BMI did not significantly impact outcome for any endpoint. BMI change did not impact BCFI or DSS after 1 or 3 years, although a mean increased BMI of 0.3 was associated with better OS (P = 0.02) after 1 year. With the administration of trastuzumab (N = 1395) baseline BMI and BMI change did not significantly impact outcomes. CONCLUSIONS: Higher baseline BMI and BMI increases negatively affected outcomes only in pre-/peri-/early post-menopausal trial patients. Otherwise, BMI increases similar to those expected in healthy women either did not impact outcome or were associated with better outcomes. CLINICAL TRIALS NUMBERS: CAN-NCIC-MA5; National Cancer Institute (NCI)-V90-0027; MA.12-NCT00002542; MA.14-NCT00002864; MA.21-NCT00014222; HERA, NCT00045032;CAN-NCIC-MA24; MA-27-NCT00066573.

Real world patterns of care in HER2-overexpressing breast cancer: Results of a survey of TEACH clinical trial investigators in 2011.

BACKGROUND: HER2-overexpressing breast cancer (BC) is common among young patients and poses a public health burden. Adjuvant anti-HER2/neu therapy with trastuzumab reduces the risk of recurrence and improves survival. METHODS: A web-based survey was sent to 386 physicians of the "TEACH" trial in 2011 to determine access to HER2/neu testing and treatment patterns for HER2-overexpressing BC. RESULTS: There were 151 responders (39%) from 28 countries. Ninety-seven percent reported HER2/neu expression is routinely measured in their institutions by immunohistochemistry (85%), FISH (80%) and other methods (16%). Twenty percent of responders from Asia reported that the test was not routinely available. Forty-eight percent of participants reported instances when adjuvant HER2-directed therapy was recommended to a patient who eventually did not receive it. Reasons for not receiving trastuzumab was cost (73%, p < 0.0001) in low- and middle-income countries and co-morbidities in high-income countries (43%, p = 0.003). CONCLUSIONS: This survey reflects the availability of HER2/neu testing and anti-HER2/neu therapy among physicians who participated in TEACH. A high proportion of women with HER2-overexpressing BC may not receive standard adjuvant therapy due to unavailability of the test and cost of therapy. Despite having some limitations, such as a possible selection bias of participating physicians, variable definitions of access to healthcare among respondents, and changes in trastuzumab availability since 2011, our results demonstrate that access to care and region of practice impact the implementation of cancer treatments.

New onset vasomotor symptoms but not musculoskeletal symptoms associate with clinical outcomes on extended adjuvant letrozole - Analyses from NCIC CTG MA.17.

PURPOSE: New onset symptoms on adjuvant aromatase inhibitors for hormone receptor positive early breast cancer may associate with clinical outcomes. We performed this exploratory analysis of the association of new onset musculoskeletal (MSK) and vasomotor (VM) symptoms with clinical outcomes in the NCIC CTG MA.17 trial 5 years of extended adjuvant endocrine therapy with letrozole after tamoxifen. METHODS: Symptoms were collected at baseline, 1, 6, and every 12 months on study. Multivariate Cox Models adjusting for age, nodal status, duration of tamoxifen and prior chemotherapy were used to compare disease-free survival (DFS), distant disease-free survival (DDFS), and overall survival (OS) based on data collected before, and after, the unblinding between women with VM or MSK symptoms and those without. RESULTS: Data post-unblinding showed new VM symptoms on extended letrozole significantly improved DFS and DDFS when occurring 1 month (DFS HR 0.52, 95% CI, 0.28-0.96; p = 0.04; DDFS HR 0.49, 95% CI, 0.24-0.99; p = 0.046) and 6 months (DFS HR 0.43, 95% CI, 0.24-0.78; p = 0.006; DDFS HR 0.44, 95% CI, 0.22-0.85; p = 0.02) after treatment initiation. Those with new VM symptoms at 12 months also had a significantly better DFS (HR 0.47, 95% CI 0.26, 0.84; P = 0.01) and a trend in improved DDFS. Only a trend to improved OS was found for those with VM symptoms 6 month after treatment. No significant improvement was found for those with new MSK symptoms at any time point or for any endpoint. CONCLUSIONS: New onset VM symptoms with extended letrozole may be useful in predicting treatment benefit.

Drug withdrawal in women with progressive metastatic breast cancer while on aromatase inhibitor therapy.

BACKGROUND: Acquiring resistance to endocrine therapy is common in metastatic hormone-receptor-positive breast cancer (MBC). These patients most often transition either to next-line endocrine therapy or to systemic chemotherapy. However, withdrawal of endocrine therapy and observation as is selectively practiced in prostate cancer is another potential strategy for breast cancer patients. METHODS: A prospective, single-arm phase II trial of aromatase inhibitor (AI) withdrawal was performed in women with MBC, who had disease progression on AI therapy. The primary objective was to estimate the clinical benefit rate (defined as complete or partial response, or stable disease for at least 24 weeks, by RECIST criteria). Participants were monitored clinically and radiographically off all therapy at 8, 16 and 24 weeks after treatment and every 12 weeks thereafter until disease progression. RESULTS: Twenty-four patients (of 40 intended) were enrolled when the study was closed due to slow accrual. Clinical benefit rate overall was 46% (95% CI 26% to 67%). Median progression-free survival from time of AI withdrawal was 4 months. Two patients have remained progression free, off all treatment, for over 60 months. CONCLUSIONS: Despite suboptimal patient accrual, our results suggest that selected patients with metastatic breast cancer progressing on AI therapy can experience disease stabilisation and a period of observation after AI withdrawal. A randomised phase II trial is planned.

Impact of premenopausal status at breast cancer diagnosis in women entered on the placebo-controlled NCIC CTG MA17 trial of extended adjuvant letrozole.

BACKGROUND: MA17 showed improved outcomes in postmenopausal women given extended letrozole (LET) after completing 5 years of adjuvant tamoxifen. PATIENTS AND METHODS: Exploratory subgroup analyses of disease-free survival (DFS), distant DFS (DDFS), overall survival (OS), toxic effects and quality of life (QOL) in MA17 were performed based on menopausal status at breast cancer diagnosis. RESULTS: At diagnosis, 877 women were premenopausal and 4289 were postmenopausal. Extended LET was significantly better than placebo (PLAC) in DFS for premenopausal [hazard ratio (HR) = 0.26, 95% confidence interval (CI) 0.13-0.55; P = 0.0003] and postmenopausal women (HR = 0.67; 95% CI 0.51-0.89; P = 0.006), with greater DFS benefit in those premenopausal (interaction P = 0.03). In adjusted post-unblinding analysis, those who switched from PLAC to LET improved DDFS in premenopausal (HR = 0.15; 95% CI 0.03-0.79; P = 0.02) and postmenopausal women (HR = 0.45; 95% CI 0.22-0.94; P = 0.03). CONCLUSIONS: Extended LET after 5 years of tamoxifen was effective in pre- and postmenopausal women at diagnosis, and significantly better in those premenopausal. Women premenopausal at diagnosis should be considered for extended adjuvant therapy with LET if menopausal after completing tamoxifen.

A randomized, placebo-controlled trial (NCIC CTG MAP.2) examining the effects of exemestane on mammographic breast density, bone density, markers of bone metabolism and serum lipid levels in postmenopausal women.

We hypothesized that exemestane (EXE) would reduce mammographic breast density and have unique effects on biomarkers of bone and lipid metabolism. Healthy postmenopausal women were randomized to EXE (25 mg daily) or placebo (PLAC) for 12 months and followed for a total of 24 months. The primary endpoint was change in percent breast density (PD) between the baseline and 12-month mammograms and secondary endpoints were changes in serum lipid levels, bone biomarkers, and bone mineral density (BMD). Ninety-eight women were randomized (49 to EXE; 49 to PLAC) and 65 had PD data at baseline and 12 months. Among women treated with EXE, PD was not significantly changed from baseline at 6, 12, or 24 months and was not different from PLAC. EXE was associated with significant percentage increase from baseline in N-telopeptide at 12 months compared with PLAC. No differences in percent change from baseline in BMD (lumbar spine and femoral neck) were observed between EXE and PLAC at either 12 or 24 months. Patients on EXE had a significantly larger percent decrease in total cholesterol than in the PLAC arm at 6 months and in HDL cholesterol at 3, 6, and 12 months. No significant differences in percent change in LDL or triglycerides were noted at any time point between the two treatment arms. EXE administered for 1 year to healthy postmenopausal women did not result in significant changes in mammographic density. A reversible increase in the bone resorption marker N-telopeptide without significant change in bone specific alkaline phosphatase or BMD during the 12 months treatment period and 1 year later was noted. Changes in lipid parameters on this trial were modest and reversible.

A randomized, placebo-controlled trial (NCIC CTG MAP1) examining the effects of letrozole on mammographic breast density and other end organs in postmenopausal women.

Mammographically detected breast density has been correlated with breast cancer risk. Breast density appears to be influenced by hormonal factors including increasing age, postmenopausal status, number of pregnancies, lower body weight, hormone replacement therapy, and tamoxifen therapy. The aromatase inhibitor letrozole profoundly reduces breast and circulating estrogen levels in postmenopausal women. We hypothesize that letrozole may reduce breast density and report here on its effects on mammographic breast density, bone mineral density (BMD), bone biomarkers, plasma hormone, and serum lipid levels. MAP1 was a multicenter, randomized, double-blind, placebo-controlled, feasibility trial in which postmenopausal women with or without prior invasive breast cancer were randomized in a 2:1 ratio of letrozole (2.5 mg daily) or placebo for 12 months and followed for a total of 24 months. Eligible women had an estimated >25% breast density on baseline mammogram. The primary endpoint was change in percent breast density (PD) between the baseline and 12-month mammograms as estimated by a computer-assisted thresholding program. Baseline and 12-month mammographic density was also assessed in a blinded manner by visual inspection. Secondary endpoints included changes in serum hormones, plasma lipid levels, bone biomarkers, and BMD. Data are available for 67 women (44 on letrozole and 23 on placebo). No significant changes in PD were noted between the treatment arms at either 12 or 24 months. No distinguishable difference in density measurements by visual inspection were noted between baseline and 12-month mammograms. A significant decrease in percentage change in T-score of the femoral neck at 12 months was noted in the letrozole arm without other significant changes in BMD parameters. Lipid values did not differ between treatment groups except for a borderline significant decrease in total cholesterol at 3 months among women treated with letrozole. Letrozole therapy was associated with a significant reduction in mean serum estradiol, estrone, and estrone sulfate levels at 12 months, but not at 24 months. A significant increase in serum IGF-1 levels was also noted in the letrozole group compared to the placebo group at both 12 and 24 months. To conclude, compared with placebo, 12 months of letrozole therapy does not appear to have a significant effect on mammographic PD. Twelve months of letrozole was associated with a decrease of uncertain clinical significance in the T-score of the femoral neck at 12 months which was reversible at 24 months with recovery of estrogen levels. Letrozole therapy was found to increase IGF-1 levels at 12 and 24 months.

Intent-to-treat analysis of the placebo-controlled trial of letrozole for extended adjuvant therapy in early breast cancer: NCIC CTG MA.17.

BACKGROUND: MA.17 evaluated letrozole or placebo after 5 years of tamoxifen and showed significant improvement in disease-free survival (DFS) for letrozole [hazard ratio (HR) 0.57, P = 0.00008]. The trial was unblinded and placebo patients were offered letrozole. PATIENTS AND METHODS: An intent-to-treat analysis of all outcomes, before and after unblinding, on the basis of the original randomization was carried out. RESULTS: In all, 5187 patients were randomly allocated to the study at baseline and, at unblinding, 1579 (66%) of 2383 placebo patients accepted letrozole. At median follow-up of 64 months (range 16-95), 399 recurrences or contralateral breast cancers (CLBCs) (164 letrozole and 235 placebo) occurred. Four-year DFS was 94.3% (letrozole) and 91.4% (placebo) [HR 0.68, 95% confidence interval (CI) 0.55-0.83, P = 0.0001] and showed superiority for letrozole in both node-positive and -negative patients. Corresponding 4-year distant DFS was 96.3% and 94.9% (HR 0.80, 95% CI 0.62-1.03, P = 0.082). Four-year overall survival was 95.1% for both groups. The annual rate of CLBC was 0.28% for letrozole and 0.46% for placebo patients (HR 0.61, 95% CI 0.39-0.97, P = 0.033). CONCLUSIONS: Patients originally randomly assigned to receive letrozole within 3 months of stopping tamoxifen did better than placebo patients in DFS and CLBC, despite 66% of placebo patients taking letrozole after unblinding.

Screening mammography for young women treated with supradiaphragmatic radiation for Hodgkin's lymphoma.

BACKGROUND: Female survivors of Hodgkin's lymphoma (HL) treated with supradiaphragmatic radiation therapy (SRT) are at increased risk of breast cancer (BC), but there is little data on the optimal screening strategy. PATIENT AND METHODS: We report a prospective surveillance study of women treated for HL with SRT before age 30 participating in a high-risk screening clinic. Starting 8 years after treatment, women received annual mammography and clinical follow-up from 1997 to 2006. Method of detection and characteristics of BCs were identified. RESULTS: In all, 115 female HL survivors attended at least one clinic; 100 participated in annual surveillance. The majority had mammography alone; adjunctive magnetic resonance imaging (MRI) was used more frequently in women with high breast density (P = 0.025). Median age at first mammogram was 36 years and decreased with more recent year of diagnosis. Twelve of the 100 participating women (12%) were diagnosed with BC after a median of 5 years of surveillance (range, 1-9). Seven BCs presented as palpable masses [six invasive, one ductal carcinoma in situ (DCIS)], five were detected by mammography (one invasive, four DCIS). CONCLUSIONS: Despite earlier initiation of mammographic screening, most BCs were detected clinically and had unfavorable pathologic characteristics. Evaluation of more intensive screening and the contribution of MRI for earlier detection is warranted.

Pilot study of the impact of letrozole vs. placebo on breast density in women completing 5 years of tamoxifen.

Breast density, a strong risk factor for breast cancer, is reduced by the anti-estrogen, tamoxifen (TAM). We examined whether aromatase inhibitor (AI) therapy results in further reductions in breast density among women completing 5 years of TAM. Among a sample of women with early-onset breast cancer who were randomized to letrozole (LET)(n=56) or placebo (PLAC)(n=48) after 5 years of TAM, we examine the change in percent density at 9-15 months as well as a per-year change in PD by treatment group. There was no difference in the adjusted mean change (-1.0%, LET; -0.3%, PLAC (P=0.58)) or the percentage change (-2.7%, LET; -3.0%, PLAC (P=0.96)) in PD between treatment groups at 9-15 months. Results were similar for longitudinal change (-0.68% per year, LET; -0.12% per year, PLAC (P=0.23)). Breast density does not appear to be a clinically relevant biomarker in women who already have low PD following 5 years of TAM.

Clinical outcomes of ethnic minority women in MA.17: a trial of letrozole after 5 years of tamoxifen in postmenopausal women with early stage breast cancer.

BACKGROUND: Aromatase inhibitors are widely employed in the adjuvant treatment of early stage breast cancer. The impact of aromatase inhibitors has not been established in ethnic minority women. PATIENTS AND METHODS: The purpose of this study was to evaluate the impact of letrozole on minority women in MA.17, a placebo-controlled trial of letrozole following 5 years of tamoxifen in postmenopausal women with early stage breast cancer. Retrospective comparison of disease-free survival (DFS), side effects, and mean changes in quality of life (QOL) scores from baseline between Caucasian and minority women was performed. RESULTS: Minority (n = 352) and Caucasian (n = 4708) women were analyzed. There was no difference between these groups in DFS (91.6% versus 92.4% respectively for 4 year DFS). Letrozole, compared with placebo, significantly improved DFS for Caucasians (HR = 0.55; P < 0.0001) but not for minorities (HR = 1.39; P = 0.53). Among women who received letrozole, minorities had a significantly lower incidence of hot flashes (49% versus 58%; P = 0.02), fatigue (29% versus 39%; P = 0.005), and arthritis (2% versus 7%; P = 0.006) compared with Caucasians. Mean change in QOL scores for minority women who received letrozole demonstrated improved mental health at the 6-month assessment (P = 0.02) and less bodily pain at the 12-month assessment (P = 0.046). CONCLUSION: Letrozole improved DFS in Caucasians but a definite benefit in minority women has not yet been demonstrated. Minority women tolerated letrozole better than Caucasians in terms of toxicity. These results need confirmation in other trials of aromatase inhibitors.

The extended adjuvant NCIC CTG MA.17 trials: initial and rerandomization studies.

Based upon the results of the NCIC CTG MA.17 trial, letrozole has become the only approved aromatase inhibitor (AI) in the extended adjuvant treatment setting following 5 years of tamoxifen therapy. In this trial, the AI letrozole decreased the overall risk of breast cancer recurrence by 42% compared with placebo in postmenopausal women completing 5 years of tamoxifen. The benefit of letrozole exceeded the expected difference after median follow-up of more than 2 years and led to the unblinding of the trial. The 30-month updated analyses found a 4.8%, 4-year disease-free survival improvement overall, an improvement in distant disease-free recurrence in both node-negative and node-positive patients, and a survival benefit for node-positive patients. Generally well tolerated, letrozole caused some adverse events including arthralgias and osteoporosis. However, results from the Zometa-Femara adjuvant synergy trial (Z-FAST) suggest that zoledronic acid, when used concomitantly with letrozole, is able to manage bone loss in postmenopausal women with early breast cancer.

The influence of letrozole on serum lipid concentrations in postmenopausal women with primary breast cancer who have completed 5 years of adjuvant tamoxifen (NCIC CTG MA.17L).

BACKGROUND: The purpose of this study was to evaluate changes in serum lipid parameters {cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides and lipoprotein(a) [Lp(a)]}, in postmenopausal women receiving letrozole or placebo after adjuvant tamoxifen for early stage breast cancer (NCIC CTG MA.17L). PATIENTS AND METHODS: MA.17L is a substudy of MA.17, a randomized, double-blind, placebo-controlled trial of letrozole 2.5 mg taken daily for 5 years in postmenopausal women with primary breast cancer completing approximately 5 years of prior adjuvant tamoxifen. Patients consenting to participate in this companion study had blood drawn and lipid parameters (total cholesterol, HDL cholesterol, LDL cholesterol, Lp(a), triglycerides) evaluated at baseline, 6 months, 12 months and yearly thereafter until completion of protocol therapy. It was required that women be non-hyperlipidemic and not taking lipid-lowering drugs at time of entry on this trial. RESULTS: Three hundred and forty seven women were enrolled in the study. The letrozole and the placebo groups demonstrated marginally significant differences in the percentage change from baseline in HDL cholesterol at 6 months (P=0.049), in LDL cholesterol at 12 months (P=0.033) and triglycerides at 24 months (P=0.036). All comparisons of lipid parameters at other time points were not significantly different between the two treatment groups. No statistically significant differences in the number of patients exceeding the thresholds defined for the lipid parameters were found between the two treatment groups. CONCLUSIONS: The MA.17 trial demonstrated a significant improvement in disease-free survival with the use of letrozole as extended adjuvant therapy post tamoxifen. Results from this study suggests that letrozole does not significantly alter serum cholesterol, HDL cholesterol, LDL cholesterol, triglycerides or Lp(a) in non-hyperlidiemic postmenopausal women with primary breast cancer treated up to 36 months following at least 5 years of adjuvant tamoxifen therapy. These findings further support the tolerability of extended adjuvant letrozole in postmenopausal women following standard tamoxifen therapy.

The steroidal aromatase inhibitor exemestane prevents bone loss in ovariectomized rats.

The irreversible steroidal aromatase inhibitor exemestane (EXE) is one of three third generation aromatase inhibitors currently prescribed for advanced breast cancer in postmenopausal women. Its principal mechanism of action is to reduce estrogen by inhibiting its synthesis. In addition to its efficacy against breast cancer, its effects on other organs are important, especially when given to women with good-prognosis breast cancer or potentially to healthy women at increased risk of developing breast cancer. The purpose of this study was to evaluate the effects of EXE on bone and lipid metabolism in ovariectomized (OVX) rats. Ten-month-old Sprague-Dawley female rats were sorted into intact controls, intact + EXE, OVX controls, and OVX + EXE groups, and treated by weekly intramuscular injection with vehicle or 100 mg/kg EXE for 16 weeks. The bone mineral density (BMD), mechanical testing, histomorphometry, bone resorption marker-serum pyridinoline (PYD), and bone formation marker-serum osteocalcin (OC) were used to determine the effects of treatment on bone. In addition, total serum cholesterol, triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) were determined. BMD of the lumbar spine and femur were 11% and 7%, respectively, higher in OVX animals given EXE than in OVX controls (all Ps<0.001). Significant increases in the bending strength and toughness of the femora as well as the compressive strength and elastic modulus of the vertebrae were observed in OVX rats given EXE (all Ps<0.02 vs. OVX controls). Trabecular bone volume (BV) was significantly higher in OVX rats treated with EXE than in OVX controls (P<0.0001). In OVX animals, EXE reduced the OVX-induced increase of serum PYD by 96% (P<0.0001), and the OVX-induced increase of serum OC was completely prevented by treatment with EXE. In OVX animals, EXE resulted in a 28% reduction of serum cholesterol (P<0.0001) and reduced LDL by 64% compared with OVX controls (P<0.0001). The positive results of EXE on bone and lipid metabolism in the OVX rat model merit further investigation of the effects of EXE in postmenopausal women.

Identification of a novel transcriptional repressor element located in the first intron of the human BRCA1 gene.

Loss or lowered expression of BRCA1 in non-familial breast cancer has been shown in several recent studies. Understanding how BRCA1 expression is regulated should provide new insights into the role of BRCA1 in sporadic breast cancer. We have recently identified a critical 18-base pair (bp) DNA element within the minimal BRCA1 promoter whereupon the formation of a specific protein-DNA complex and transcription of BRCA1 is dependent. We now report a non tissue-specific transcriptional repressor activity, located more than 500 bp into the first intron of BRCA1. Progressive deletions from the 3'-end of intron 1 and reporter gene assays localized the repressor activity to an 83-bp region. Electrophoretic mobility shift assays with this 83 bp DNA and various sub-fragments of it showed binding of nuclear proteins to a 36 bp BstNI-BseRI fragment. Functional transcriptional repression by this 36 bp DNA could be conferred on a heterologous thymidine kinase promoter. Analysis of multiple reporter gene constructs containing the BRCA1 genomic region driving transcription in both directions suggests that the putative negative regulatory element functions to block transcription only in the BRCA1 direction, although the promoter is shared by the divergently transcribed NBR2 gene.

Aromatase inhibitors in the treatment and prevention of breast cancer.

PURPOSE: The purpose of this article is to provide an overview of the current clinical status and possible future applications of aromatase inhibitors in breast cancer. METHODS: A review of the literature on the third-generation aromatase inhibitors was conducted. Some data that have been presented but not published are included. In addition, the designs of ongoing trials with aromatase inhibitors are outlined and the implications of possible results discussed. RESULTS: All of the third-generation oral aromatase inhibitors--letrozole, anastrozole, and vorozole (nonsteroidal, type II) and exemestane (steroidal, type I)--have now been tested in phase III trials as second-line treatment of postmenopausal hormone-dependent breast cancer. They have shown clear superiority compared with the conventional therapies and are therefore considered established second-line hormonal agents. Currently, they are being tested as first-line therapy in the metastatic, adjuvant, and neoadjuvant settings. Preliminary results suggest that the inhibitors might displace tamoxifen as first-line treatment, but further studies are needed to determine this. CONCLUSION: The role of aromatase inhibitors in premenopausal breast cancer and in combination with chemotherapy and other anticancer treatments are areas of future exploration. The ongoing adjuvant trials will provide important data on the long-term safety of aromatase inhibitors, which will help to determine their suitability for use as chemopreventives in healthy women at risk of developing breast cancer.

Chemoprevention with aromatase inhibitors--trial strategies.

Estrogen and its catechol metabolites from both the circulation and synthesized within the breast are important in the pathogenesis of breast cancer. Blocking estrogen's effects on the breast with selective estrogen receptor modulators (SERMS) is an ongoing strategy. Thus, tamoxifen and raloxifene reduce risk as monotherapy. Aromatase (estrogen synthetase) inhibitors are a logical alternative to SERMS. To date, SERMS have demonstrated reduction only in estrogen-progesterone receptor positive cancers without reduction in receptor negative tumors. By inhibiting the parent estrogens and their catechol metabolites, true prevention of cancer initiation might occur and reduction not only in the receptor positive but also negative tumors might result. Ongoing adjuvant breast cancer trials are exploring aromatase inhibitors as alternatives to tamoxifen, or in sequence or in combination with tamoxifen. Relative efficacies including reduction in contralateral breast cancer, toxicities and end-organ effects and impact on quality of life, are being explored. Data from these trials will help to guide future chemoprevention strategies. Proof of principal trials in 'high risk' cohorts such as premalignant breast lesions, dense screening mammograms, high plasma estradiol levels or increased bone density are already ongoing. Issues such as dose, schedule, therapeutic index and mono versus combination therapy are important to define.