The Prosigna 50-gene profile and responsiveness to adjuvant anthracycline-based chemotherapy in high-risk breast cancer patients.

The DBCG89D trial randomized high-risk early breast cancer patients to adjuvant CMF (cyclophosphamide, methotrexate and fluorouracil) or CEF (cyclophosphamide, epirubicin and fluorouracil). Prosigna assays were performed by researchers with no access to clinical data. Time to distant recurrence (DR) was the primary endpoint, time to recurrence (TR) and overall survival (OS) secondary. Among the 980 Danish patients enrolled, Prosigna results were obtained in 686. Continuous ROR score was associated with DR for CMF (adjusted hazard ratio (HR) 1.20, 95% CI 1.09-1.33), and for CEF (HR 1.04, 95% CI 0.92-1.18), P interaction = 0.06. DR was significantly longer in CEF compared to CMF treated patients with Her2-enriched tumors (HR 0.58, 95% CI 0.38-0.86), but not in patients with luminal tumors. Heterogeneity of treatment effect was significant for TR and OS. In this prospective-retrospective analysis, patients with Her2-enriched breast cancer derived substantial benefit from anthracycline chemotherapy whereas anthracyclines are not an essential component of chemotherapy for patients with luminal subtypes. The benefit of CEF vs. CMF correlated with increasing ROR Score.

Two years of tamoxifen or no adjuvant systemic therapy for patients with high-risk breast cancer: long-term follow-up of the Copenhagen breast cancer trial.

BACKGROUND: The Copenhagen Breast Cancer Trial (CBCT) randomly assigned patients with early breast cancer to two years of tamoxifen or placebo and we evaluated the effect over the following four decades. PATIENT AND METHODS: Between 1975 and 1978, 327 patients with primary breast cancer were randomly assigned to two years of daily placebo or tamoxifen. Survival statistics was collected from the Danish Civil Registration System. RESULTS: The five-year invasive breast cancer recurrence (BCR) rate was 43.2% in the placebo arm and 31.9% in the tamoxifen arm. Compared with the placebo arm the hazard ratio for a BCR event was 0.73 in the tamoxifen arm (p = .07). With an estimated median follow-up on overall survival of 40.9 years, 154 and 145 patients had died in the placebo and tamoxifen arm, respectively. After adjustment for baseline characteristics a significant reduction in mortality was obtained from tamoxifen (HR 0.79; p = .04). CONCLUSION: Two years of adjuvant tamoxifen resulted in a sustained reduction in mortality in pre- and postmenopausal high-risk breast cancer patients with long-term follow-up data.

The clinical database and implementation of treatment guidelines by the Danish Breast Cancer Cooperative Group in 2007-2016.

BACKGROUND: Since 40 years, Danish Breast Cancer Cooperative Group (DBCG) has provided comprehensive guidelines for diagnosis and treatment of breast cancer. This population-based analysis aimed to describe the plurality of modifications introduced over the past 10 years in the national Danish guidelines for the management of early breast cancer. By use of the clinical DBCG database we analyze the effectiveness of the implementation of guideline revisions in Denmark. METHODS: From the DBCG guidelines we extracted modifications introduced in 2007-2016 and selected examples regarding surgery, radiotherapy (RT) and systemic treatment. We assessed introduction of modifications from release on the DBCG webpage to change in clinical practice using the DBCG clinical database. RESULTS: Over a 10-year period data from 48,772 patients newly diagnosed with malignant breast tumors were entered into DBCG's clinical database and 42,197 of these patients were diagnosed with an invasive carcinoma following breast conserving surgery (BCS) or mastectomy. More than twenty modifications were introduced in the guidelines. Implementations, based on prospectively collected data, varied widely; exemplified with around one quarter of the patients not treated according to a specific guideline within one year from the introduction, to an almost immediate full implantation. CONCLUSIONS: Modifications of the DBCG guidelines were generally well implemented, but the time to full implementation varied from less than one year up to around five years. Our data is registry based and does not allow a closer analysis of the causes for delay in implementation of guideline modifications.

Forty years of landmark trials undertaken by the Danish Breast Cancer Cooperative Group (DBCG) nationwide or in international collaboration.

BACKGROUND: Over the past 40 years the Danish Breast Cancer Cooperative Group (DBCG) has made significant contributions to improve outcome and to make treatment of patients with early breast cancer more tolerable through nationwide and international trials evaluating loco-regional and systemic treatments. These trials have been instrumental to establish standards for the treatment of early breast cancer. METHODS: The DBCG 82 trials had a global impact by documenting that the significant gain in loco-regional recurrence from postmastectomy radiation added to systemic therapy was associated with a reduction in distant recurrence and mortality in high-risk pre- and postmenopausal patients. The DBCG trials comparing breast conserving surgery and radiotherapy with mastectomy and more recently the trial of internal mammary node irradiation also had a major impact of practice. The trials initiated by the DBCG 40 years ago on tamoxifen and cyclophosphamide based chemotherapy became instrumental for the development of adjuvant systemic therapy not only due to their positive results but by sharing these important data with other members of the Early Breast Cancer Trialist' Collaborative Group (EBCTCG). Trials from the DBCG have also been important for highlighting the relative importance of anthracyclines and taxanes in the adjuvant setting. Furthermore, DBCG has made a major contribution to the development of aromatase inhibitors and targeted adjuvant treatment for human epidermal growth factor receptor 2 positive breast cancers. RESULTS: The substantial impact of these treatment improvements is illustrated by a 46.7% 10-year overall survival of early breast cancer patients treated in 1978-1987 compared to 71.5% for patients treated 2008-2012. CONCLUSIONS: The trials conducted and implemented by the DBCG appear to have a major impact on the substantial survival improvements in breast cancer.

The occurrence of fractures after adjuvant treatment of breast cancer: a DBCG register study.

BACKGROUND: Adjuvant treatment in breast cancer patients especially with aromatase inhibitors (AIs) has adverse effects on bone metabolism resulting in an increased occurrence of fractures. In order to demonstrate this occurrence, long-term follow-up studies are necessary. From several national registries in Denmark, it is possible to link data from different sources and analyze this issue. METHODS: A study cohort of 68,842 breast cancer patients prospectively diagnosed and registered in the Danish Breast Cancer Cooperative Group's database during the period 1995-2012 formed the basis of the analysis. These data were matched with data on all types of fractures from the Danish National Patient Register and vital data from the Danish Civil Registration System. RESULTS: After data cleaning 66,502 patients were available for analysis and 16,360 of these had incurred 20,341 fractures with 13,182 patients having just one fracture. These fractures were distributed over 214 specific fracture sites. An extended multivariable Cox regression model revealed significant association between the occurrence of fractures and age, menopause, Charlson comorbidity index (CCI) and endocrine therapy such that late menopause and tamoxifen treatment were associated with a lower occurrence and AI treatment, age and CCI were associated with a higher occurrence of fractures. CONCLUSION: Before advising adjuvant therapy with AIs fragile patients with chronic diseases should receive special attention in order to reduce the incidence of fractures in this vulnerable group of patients.

Adjuvant Cyclophosphamide and Docetaxel With or Without Epirubicin for Early TOP2A-Normal Breast Cancer: DBCG 07-READ, an Open-Label, Phase III, Randomized Trial.

Purpose Administration of anthracycline and taxane therapy in the adjuvant setting is considered a standard for breast cancer. We evaluated a non-anthracycline-based regimen in TOP2A-normal patients. Patients and Methods In this multicenter, open-label, phase III trial, 2,012 women with early TOP2A-normal breast cancer and at least one high-risk factor were randomly assigned to receive six cycles of docetaxel (75 mg/m2) and cyclophosphamide (600 mg/m2) every 3 weeks (DC) or three cycles of epirubicin (90 mg/m2) and cyclophosphamide (600 mg/m2) followed by three cycles of docetaxel (100 mg/m2; EC-D). The primary end point was disease-free survival (DFS) after a median of 5 years of follow-up. Secondary end points were patient-reported toxicity, overall survival (OS), and distant disease-free survival. Results At a median estimated potential follow-up of 69 months, 5-year DFS was 87.9% (95% CI, 85.6% to 89.8%) in the EC-D arm and 88.3% (95% CI, 86.1% to 90.1%) in the DC arm. There was no significant difference in the risk of DFS events (hazard ratio [HR], 1.00; 95% CI, 0.78 to 1.28; P = 1.00), distant disease-free survival (HR, 1.12; 95% CI, 0.86 to 1.47; P = .40), or mortality (HR, 1.15; 95% CI, 0.83 to 1.59; P = .41) in the intent-to-treat analysis. A significant interaction between menopausal status and treatment group was observed for DFS ( P = .04) but not for OS ( P = .07). Patients with grade 3 tumors derived most benefit from DC, and patients with grade 1 to 2 tumors derived most benefit from EC-D (DFS: interaction P = .02; and OS: interaction P = .03). Patients receiving EC-D reported significantly more stomatitis, myalgia or arthralgia, vomiting, nausea, fatigue, and peripheral neuropathy, whereas edema was more frequent after DC. Conclusion This study provides evidence to support no overall outcome benefit from adjuvant anthracyclines in patients with early TOP2A-normal breast cancer.

Danish Breast Cancer Cooperative Group.

AIM OF DATABASE: Danish Breast Cancer Cooperative Group (DBCG), with an associated database, was introduced as a nationwide multidisciplinary group in 1977 with the ultimate aim to improve the prognosis in breast cancer. Since then, the database has registered women diagnosed with primary invasive nonmetastatic breast cancer. The data reported from the departments to the database included details of the characteristics of the primary tumor, of surgery, radiotherapy, and systemic therapies, and of follow-up reported on specific forms from the departments in question. DESCRIPTIVE DATA: From 1977 through 2014, ~110,000 patients are registered in the nationwide, clinical database. The completeness has gradually improved to more than 95%. DBCG has continuously prepared evidence-based guidelines on diagnosis and treatment of breast cancer and conducted quality control studies to ascertain the degree of adherence to the guidelines in the different departments. CONCLUSION: Utilizing data from the DBCG database, a long array of high-quality DBCG studies of various designs and scope, nationwide or in international collaboration, have contributed to the current updating of the guidelines, and have been an instrumental resource in the improvement of management and prognosis of breast cancer in Denmark. Thus, since the establishment of DBCG, the prognosis in breast cancer has continuously improved with a decrease in 5-year mortality from ~37% to 15%.

Improvements in breast cancer survival between 1995 and 2012 in Denmark: The importance of earlier diagnosis and adjuvant treatment.

Background Breast cancer mortality has declined from 1995 through 2012 which may be attributed to earlier diagnosis, changes in lifestyle risk factors, and improved treatments. To a large extent the relative contribution of these modalities are unknown. Mammography screening was introduced late in Denmark; in 1995 around 20% of the Danish female population aged 50-69 was covered by population-based screening, and this was in 2008 extended to the entire population. Breast conserving surgery gradually replaced mastectomy, and sentinel node biopsy was introduced. In the same period adjuvant treatment was extended considerable. Methods A population-based study of 68 842 breast cancer patients registered in the clinical database of the Danish Breast Cancer Cooperative Group in 1995-2012. Comprehensive data on prognostic factors, comorbidity and treatment together with complete follow-up for survival were used to evaluate improvements in mortality and standardized mortality rate in successive time periods. Results The results from this study demonstrated a significant improvement in prognosis in successive time periods covering 1995-2012. Apart from patients with a high Charlson Comorbidity Index (CCI) improvements were seen in all subgroups of patients. Prognostic factors were more favorable in the latest time period accordingly to the introduction of nationwide screening. In the study period adjuvant treatment was extended considerable. Conclusion The impact of screening was by nature of limited magnitude. The modified treatment strategies implemented by the use of nationwide guidelines seemed to have a major impact on the substantial survival improvements.

Excess mortality in postmenopausal high-risk women who only receive adjuvant endocrine therapy for estrogen receptor positive breast cancer.

BACKGROUND: Omission of chemotherapy may affect mortality in postmenopausal high-risk women despite appropriate adjuvant endocrine therapy for estrogen receptor (ER) positive breast cancer. The aim of this study was to determine how all-cause mortality rate in these patients compares to that of the general female population. Furthermore, to identify a subset without excess mortality using clinical and pathological characteristics. PATIENTS AND METHODS: From the population-based database of the Danish Breast Cancer Cooperative Group we included 6529 postmenopausal patients with ER positive high-risk breast cancer who in 1996 through 2004 by nationwide guidelines were allocated to five years of tamoxifen, an aromatase inhibitor (AI) or both in sequence. Multivariate categorical and fractional polynomials (MFP) models were used to construct prognostic subsets by clinicopathologic characteristics. RESULTS: In a multivariate model excess mortality was inversely (p < 0.0001) associated with increasing age at surgery while recurrence-free survival (RFS) was not. Non-adherence to endocrine therapy was associated with excess mortality (p = 0.0008) while treatment with an AI was associated with a less pronounced mortality excess (p = 0.03). A prognostic standard mortality rate (SMR) index (PSI) was built using the regression coefficients obtained in the MFP model, and the same risk factors were used to construct a flowchart algorithm. Both allocated 75% to a group with increased all-cause mortality as compared to the general female population, but the SMR was significantly increased (SMR 1.38; 95% CI 1.16-1.65) in 462 patients who were allocated to low-risk group by the Flowchart algorithm and to a high-risk group by PSI. CONCLUSION: Only one quarter of postmenopausal ER positive breast cancer patients are free of excess mortality when omitting adjuvant chemotherapy. Patients should be informed about importance of adherence to adjuvant endocrine therapy and inclusion of an AI. A PSI may better guide recommendations regarding adjuvant chemotherapy.

One year of adjuvant tamoxifen compared with chemotherapy and tamoxifen in postmenopausal patients with stage II breast cancer.

PURPOSE: We report the long-term results of a randomised trial comparing tamoxifen with tamoxifen plus cyclophosphamide, methotrexate and fluorouracil (CMF) in postmenopausal high-risk breast cancer patients. In addition, we analyse the prognostic and predictive value of centrally assessed subtypes. METHODS: Postmenopausal patients with breast cancer and positive nodes, deep invasion or size exceeding 5 cm were randomly assigned to 1 year of tamoxifen, or cyclophosphamide 600 mg/m2, methotrexate 40 mg/m2 and fluorouracil 600 mg/m2 intravenously on day 1 every 4 weeks for nine cycles plus tamoxifen (CMFT). Tissue microarrays were constructed retrospectively and oestrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor 2 (HER2), and proliferation-related Ki-67 antigen (Ki67) status were assessed. RESULTS: From October 1982 through March 1990 we randomised 1445 patients and 969 (67%) were eligible for the biomarker analysis. At 10-years 936 women had suffered a disease-free survival (DFS) event (tamoxifen, 495 events in 686 patients; CMFT, 441 events in 642 patients). The addition of CMF to tamoxifen significantly improved DFS (adjusted hazard ratio 0.82; 95% confidence interval (CI) 0.71-0.93; P = 0.003) but not overall survival (adjusted hazard ratio 0.95; 95% CI 0.85-1.08; P = 0.44). DFS was superior in Luminal A tumours (ER or PgR positive, HER2 negative and Ki67 ≤ 14%) when compared to Luminal B or non-luminal (ER and PgR negative) tumours. There was no statistical evidence of heterogeneity by subtype in the benefit from CMF (P(interaction) = 0.45). CONCLUSION: CMF added to 1 year of tamoxifen reduces the risk of a DFS event. The benefit from CMF was not significantly different in Luminal A and B subtypes.

Obesity and risk of recurrence or death after adjuvant endocrine therapy with letrozole or tamoxifen in the breast international group 1-98 trial.

PURPOSE: To examine the association of baseline body mass index (BMI) with the risk of recurrence or death in postmenopausal women with early-stage breast cancer receiving adjuvant tamoxifen or letrozole in the Breast International Group (BIG) 1-98 trial at 8.7 years of median follow-up. PATIENTS AND METHODS: This report analyzes 4,760 patients with breast cancer randomly assigned to 5 years of monotherapy with letrozole or tamoxifen in the BIG 1-98 trial with available information on BMI at randomization. Multivariable Cox modeling assessed the association of BMI with disease-free survival, overall survival (OS), breast cancer-free interval, and distant recurrence-free interval and tested for treatment-by-BMI interaction. Median follow-up was 8.7 years. RESULTS: Seventeen percent of patients have died. Obese patients (BMI ≥ 30 kg/m(2)) had slightly poorer OS (hazard ratio [HR] = 1.19; 95% CI, 0.99 to 1.44) than patients with normal BMI (< 25 kg/m(2)), whereas no trend in OS was observed in overweight (BMI 25 to < 30 kg/m(2)) versus normal-weight patients (HR = 1.02; 95% CI, 0.86 to 1.20). Treatment-by-BMI interactions were not statistically significant. The HRs for OS comparing obese versus normal BMI were HR = 1.22 (95% CI, 0.93 to 1.60) and HR = 1.18 (95% CI, 0.91 to 1.52) in the letrozole and tamoxifen groups, respectively. CONCLUSION: There was no evidence that the benefit of letrozole over tamoxifen differed according to patients' BMI.

Lack of independent prognostic and predictive value of centromere 17 copy number changes in breast cancer patients with known HER2 and TOP2A status.

The clinical benefit of anthracyclines has been connected to HER2 status, TOP2A status and centromere 17 copy numbers (CEN-17). Data from a clinical trial randomizing patients to anthracyclines was used to assess whether the number of CEN-17 in breast cancers may predict incremental responsiveness to anthracyclines besides what is obtained when used relatively to TOP2A and HER2. As cut sections of paraffin-embedded tissue are prone to truncation of nuclei, strict definition of ploidy levels is lacking. We therefore used normal breast tissue to assist define ploidy levels in cut sections. Fluorescence in situ hybridization (FISH) with centromere 17 (CEN-17) and TOP2A was performed on 120 normal breast specimens. The diploid CEN-17 copy number was reduced from the expected two signals in whole nuclei to an average of 1.68 signals per nucleus in cut sections of normal breast. Ploidy levels determined in normal breast were applied to data on 767 patients with known HER2 and TOP2A status randomized to anthracyclines in the DBCG 89D trial. CEN-17 ploidy levels were in cut sections from the 767 breast cancer patients established as: Haploid: ≤1.25 (10%), diploid: 1.26-2.09 (60%), triploid: 2.10-2.93 (21%), tetraploid: 2.94-3.77 (5%) or higher ploidy: ≥3.78 (4%). Amplification of HER2 and deletion of TOP2A were frequently observed in tumors with a high ploidy level. In univariate analyses increasing ploidy was associated with decreased disease-free survival (DFS) (P=0.0001) and overall survival (OS) (P<0.0001). However, in multivariate analysis CEN-17 was not established as an independent prognostic factor and was neither a statistically significant predictor of benefit from CEF (Cyclophosphamide/Epirubicin/5-Fluorouracil) compared to CMF (Cyclophosphamide/Methotrexate/5-Fluorouracil) (P(Interaction) 0.39 for DFS and 0.67 for OS). In conclusion, CEN-17 levels do not independently from TOP2A/CEN-17 ratio identify breast cancer patients who achieve an incremental benefit from adjuvant anthracyclines.

HER2 and TOP2A as predictive markers for anthracycline-containing chemotherapy regimens as adjuvant treatment of breast cancer: a meta-analysis of individual patient data.

BACKGROUND: Prediction of response to anthracycline-based therapy for breast cancer is challenging. We aimed to assess the value of HER2 and TOP2A as predictive markers of response to anthracycline-based adjuvant therapy in patients with early breast cancer. METHODS: We did a meta-analysis of individual patient data from five randomised adjuvant trials that compared anthracycline-based regimens with cyclophosphamide, methotrexate, and fluorouracil (CMF) regimens. We assessed the status of HER2 and TOP2A genes with fluorescent in-situ hybridisation. Tumour samples were submitted to an external laboratory for validation. We calculated hazard ratios (HR) to compare event-free survival (EFS) and overall survival in patients receiving anthracycline-based treatment with those receiving CMF in two HER2 cohorts (HER2 amplified and non-amplified tumours) and in three TOP2A cohorts (normal, amplified, and deleted tumours). FINDINGS: We analysed data for 3452 patients for HER2 and 3102 patients for TOP2A. For EFS, HRs were 0·89 (95% CI 0·79-1·01) for HER2 non-amplified patients and 0·71 (0·58-0·86) for HER2-amplified patients (p(interaction)=0·0485); for overall survival, HRs were 0·91 (95% CI 0·79-1·05) for HER2 non-amplified patients and 0·73 (0·59-0·89) for HER2-amplified patients (p(interaction)=0·0718). In analysis of TOP2A status, HRs for EFS were 0·88 (0·78-1·00) for normal, 0·63 (0·46-0·87) for deleted, and 0·62 (0·43-0·90) for amplified (p(interaction)=0·0513); HRs for overall survival were 0·89 (0·78-1·03) for normal, 0·68 (0·49-0·95) for deleted, and 0·67 (0·46-0·98) for amplified (p(interaction)=0·1608). When patients with TOP2A-deleted and TOP2A-amplified tumours were grouped together (altered cohort) and compared with data from patients with normal TOP2A tumours, HRs for EFS were 0·64 (0·50-0·81) for altered and 0·88 (0·78-1·00) for normal (p(interaction)=0·0183); HRs for overall survival were 0·67 (0·52-0·86) for altered and 0·89 (0·78-1·03) for normal (p(interaction)=0·0455). INTERPRETATION: Although HER2 amplification and combined TOP2A amplification and deletion may have some value in the prediction of responsiveness to anthracycline-based chemotherapy, our findings do not support the use of anthracyclines only in patients with HER2-amplified or TOP2A-aberrated tumours. FUNDING: Associazione Italiana Ricerca Cancro, Academy of Finland, Belgian Federation Against Cancer, Cancer Research UK, Les Amis de l'Institut Bordet, Scottish Breast Cancer Trials Group, NCIC Clinical Trials Group, Canadian Cancer Society Research Institute, Danish Council for Strategic Research, Pharmacia-Upjohn (now Pfizer), and Abbott Laboratories.

Mortality rates among early-stage hormone receptor-positive breast cancer patients: a population-based cohort study in Denmark.

BACKGROUND: Indications for adjuvant endocrine treatment of breast cancer have gradually increased over the past several years. We aimed to define subgroups of patients who may or may not benefit from adjuvant endocrine therapy. METHODS: A population-based cohort of systemically untreated breast cancer patients (N = 3197) were identified within the registry of the Danish Breast Cancer Cooperative Group (DBCG). The patients were node negative and had estrogen receptor-positive and/or progesterone receptor-positive tumors (except medullary tumors) and were further characterized by the following risk factors: aged 35-74 years (grouped into 5-year categories) at surgery, tumor size (≤20 mm), and histopathology (grade 1 ductal carcinoma, grade 1 or 2 invasive lobular carcinoma, other or unknown histopathology). Standardized mortality ratios (SMRs) were calculated based on the mortality rate (observed number of deaths per 100,000 person-years) among patients relative to the mortality rate in the general population of women (expected number of deaths per 100,000 person-years). The association between standardized mortality ratio and risk factors were analyzed in univariate and multivariable Poisson regression models. All findings were validated in a subsequent DBCG cohort of breast cancer patients (N = 2710). RESULTS: The median follow-up after surgery was 14.8 years. In the study population there were 970 deaths compared with expected death of 737 women, which was an excess mortality of 233 deaths (SMR = 1.32, 95% CI = 1.24 to 1.40). Mortality rates were 2356 per 100,000 person-years in the study population and 1790 per 100,000 person-years in the general population of women. The mortality rate was associated with larger tumor size (11-20 mm tumors vs 1-10 mm tumors, SMR = 1.42, 95% confidence interval [CI] = 1.31 to 1.53 vs. SMR = 1.12, 95% CI = 1.00 to 1.26). The mortality rate was also associated with age (35-59 years, SMR > 1) compared with that in the general population of age-matched women, except for a small subgroup of patients (aged 60-74 years, tumors ≤10 mm, grade 1 ductal carcinoma, and grade 1 or 2 lobular carcinoma: adjusted relative risk = 1.02, 95% CI = 0.89 to 1.16.). CONCLUSIONS: A small subgroup of breast cancer patients who were 60 years or older and had hormone-responsive early-stage tumors up to 10 mm, and received no systemic adjuvant therapy, were not at increased risk of mortality compared with women in this age-group in the general population.

Dose-tailoring of FEC adjuvant chemotherapy based on leukopenia is feasible and well tolerated. Toxicity and dose intensity in the Scandinavian Breast Group phase 3 adjuvant Trial SBG 2000-1.

UNLABELLED: The SBG 2000-1 trial is a randomised study that investigates if dose-tailored adjuvant FEC therapy based on the individual's leukocyte nadir value can improve outcome. The study has included 1535 women with medium and high-risk breast cancer. PATIENTS AND METHODS: After a first standard dosed FEC course (5-fluorouracil 600 mg/m(2), epirubicin 60 mg/mg(2) and cyclophosphamide 600 mg/m(2)), patients who did not reach leukopenia grade III or IV were randomised to standard doses (group standard) or doses tailored to achieve grade III leukopenia (group tailored) at courses 2-7. Patients who achieved leukopenia grade III or more after the first course were not randomised but continued on standard doses (group registered). RESULTS: Both planned and actually delivered number of courses (seven) were the same in all three arms. The relative dose intensity was increased by a factor of 1.31 (E 1.22, C 1.43) for patients in the tailored arm compared to the expected on standard dose. Ninety percent of the patients in the tailored arm achieved leukopenia grade III-IV compared with 29% among patients randomised to standard dosed therapy. Dose tailoring was associated with acceptable acute non-haematological toxicity with more total alopecia, nausea, vomiting and fatigue. CONCLUSION: Dose tailoring according to leukopenia was feasible. It led to an increased dose intensity and was associated with acceptable excess of acute non-haematological toxicity.

Analyses adjusting for selective crossover show improved overall survival with adjuvant letrozole compared with tamoxifen in the BIG 1-98 study.

PURPOSE: Among postmenopausal women with endocrine-responsive breast cancer, the aromatase inhibitor letrozole, when compared with tamoxifen, has been shown to significantly improve disease-free survival (DFS) and time to distant recurrence (TDR). We investigated whether letrozole monotherapy prolonged overall survival (OS) compared with tamoxifen monotherapy. PATIENTS AND METHODS: Of 8,010 postmenopausal women with hormone receptor-positive, early breast cancer enrolled on the Breast International Group (BIG) 1-98 study, 4,922 were randomly assigned to 5 years of continuous adjuvant therapy with either letrozole or tamoxifen. Of 2,459 patients enrolled in the tamoxifen treatment arm, 619 (25.2%) selectively crossed over to either adjuvant or extended letrozole after initial trial results were presented in January 2005. To gain better estimates of relative treatment effects in the presence of selective crossover, we used inverse probability of censoring weighted (IPCW) modeling. RESULTS: Weighted Cox models, by using IPCW, estimated a statistically significant, 18% reduction in the hazard of an OS event with letrozole treatment (hazard ratio [HR], 0.82; 95% CI, 0.70 to 0.95). Estimates of 5-year OS on the basis of IPCW were 91.8% and 90.4% for letrozole and tamoxifen, respectively. The HRs of DFS and TDR events by using IPCW modeling were 0.83 (95% CI, 0.74 to 0.94) and 0.80 (95% CI, 0.67 to 0.94), respectively (P < .05 for DFS, OS, and TDR). Median follow-up was 74 months. CONCLUSION: Adjuvant treatment with letrozole, compared with tamoxifen, significantly reduces the risk of death, the risk of recurrent disease, and the risk of recurrence at distant sites in postmenopausal women with hormone receptor-positive breast cancer.

Amplification of ESR1 may predict resistance to adjuvant tamoxifen in postmenopausal patients with hormone receptor positive breast cancer.

The estrogen receptor (ER) is the target of tamoxifen, but endocrine therapies do not benefit all patients with ER positive tumors. We therefore hypothesized that copy number changes in the ESR1 gene, encoding ER, confer resistance. Within a consecutive series of ER positive, postmenopausal patients allocated to 5 years tamoxifen, we identified 61 patients with recurrence less than 4 years and 48 patients without recurrence at least 7 years after initiation of adjuvant tamoxifen. Archival tissue containing primary tumor was collected from 97 patients (89%). Tumor samples were analyzed for ESR1 copy number changes using FISH with a probe covering the ESR1 gene at 6q25 and a reference probe covering the centromere of chromosome 6. The assay was validated in a material of 120 normal breast samples. FISH analysis for ESR1 was successful in 91 patients (94%). Amplification (ratio ESR1/CEN-6 ≥ 2.0) was observed in 11 of 50 (22%) patients with early recurrence, compared to two of 41 (5%) patients without recurrence. The difference is statistically significant (P = 0.033). In both groups, two patients with ESR1 deletion (ratio ESR1/CEN-6 < 0.8) were identified. ESR1 amplification was significantly associated with poor disease-free survival (P = 0.0054) and overall survival (P = 0.0004). This pilot study supports our hypothesis that ESR1 amplification is associated with a poorer outcome following adjuvant treatment with tamoxifen in ER positive early breast cancer. This study also revealed the existence of ESR1 deletions. The prognostic and predictive impact of ESR1 copy number changes needs further exploration in clinical trials.