Austrian Breast And Colorectal Cancer Study Group Research Articles

Effect of concomitant statin treatment in postmenopausal patients with hormone receptor-positive early-stage breast cancer receiving adjuvant denosumab or placebo: a post hoc analysis of ABCSG-18

BackgroundStatins are cholesterol-lowering drugs prescribed for the prevention and treatment of cardiovascular disease. Moreover, statins may possess anticancer properties and interact with receptor activator of nuclear factor κB ligand expression. We aimed at evaluating a hypothetical synergistic effect of statins with denosumab in early-stage breast cancer (BC) patients from the Austrian Breast and Colorectal Cancer Study Group (ABCSG) trial 18.Patients and methodsABCSG-18 (NCT00556374) is a prospective, randomized, double-blind, phase III study; postmenopausal patients with hormone receptor-positive BC receiving a nonsteroidal aromatase inhibitor were randomly assigned to denosumab or placebo. In this post hoc analysis, we investigated the effects of concomitant statin therapy on recurrence risk (RR) of BC, fracture risk and bone mineral density (BMD).ResultsIn the study population (n = 3420), statin therapy (n = 824) was associated with worse disease-free survival (DFS) [hazard ratio (HR) 1.35, 95% confidence interval (CI) 1.04-1.75; P = 0.023]. While no significant effect of lipophilic statins (n = 710) on RR was observed (HR 1.30, 95% CI 0.99-1.72; P = 0.062), patients on hydrophilic statins (n = 87) had worse DFS compared with patients not receiving any statins (HR 2.00, 95% CI 1.09-3.66; P = 0.026). This finding was mainly driven by the effect of hydrophilic statins on DFS in the denosumab arm (HR 2.63, 95% CI 1.21-5.68; P = 0.014). However, this effect subsided after correction for confounders in the sensitivity analysis. No association between statin use and fracture risk or osteoporosis was observed.ConclusionAccording to this analysis, hydrophilic statins showed a detrimental effect on DFS in the main model, which was attenuated after correction for confounders. Our data need to be interpreted with caution due to their retrospective nature and the low number of patients receiving hydrophilic statins.

Abstract P1-15-01: Effect of concomitant statin treatment in postmenopausal patients with hormone-receptor positive early-stage breast cancer receiving adjuvant denosumab or placebo: A post-hoc analysis of ABCSG-18

Abstract Background Statins are a common class of cholesterol-lowering drugs prescribed for the prevention and treatment of cardiovascular disease. Moreover, it was suggested that statins may possess anti-cancer properties and interact with RANK ligand expression. Therefore, we aimed at evaluating a hypothetical synergistic effect of statins with denosumab in early-stage breast cancer (BC) patients from the Austrian Breast and Colorectal Cancer Study Group (ABCSG) trial 18. Methods ABCSG-18 (NCT00556374) is a prospective, randomized, double-blind, phase III study; postmenopausal patients with hormone receptor (HR) positive BC receiving a non-steroidal aromatase inhibitor were randomly assigned to denosumab or placebo. In this post-hoc analysis, we investigated the potential effects of concomitant statin therapy on recurrence risk of BC, fracture risk and bone mineral density (BMD) using time-dependent Cox proportional hazards models. Sensitivity analyses accounting for immortal time and confounding bias were performed. Results In the analysis of the study population (n=3,420), statin therapy (n=824) was associated with worse disease-free survival (DFS) (HR 1.35, 95%; CI 1.04-1.75; p=0.023). Sensitivity analysis relativized these results (HR 1.22, 95% CI 0.94 - 1.59; p=0.14). While there was no significant effect of lipophilic statins (n=710) on recurrence risk (HR 1.30, 95% CI 0.99 - 1.72; p=0.062), patients on hydrophilic statins (n=87) had worse DFS compared with patients not receiving any statins (HR 2.00, 95% CI 1.09-3.66; p=0.026). This finding was mainly driven by the effect of hydrophilic statins on DFS in the denosumab arm (HR 2.63, 95% CI 1.21 - 5.68; p=0.014). No association between statin use and fracture risk or osteoporosis was observed. Conclusion In this population of early-stage breast cancer patients from a prospective randomized study, an association of hydrophilic statins with increased recurrence risk was observed. According to this retrospective analysis hydrophilic statins may increase recurrence risk especially in patients treated with denosumab. Still, our data need to be interpreted with caution due to their retrospective nature and the low number of patients receiving hydrophilic statins. Therefore, no final conclusion is possible. This hypothesis generating result warrants further exploration. Citation Format: Christoph Minichsdorfer, Thorsten Fuereder, Michael Leutner, Christian F. Singer, Stephanie Kacerovsky-Strobl, Daniel Egle, Richard Greil, Marija Balic, Florian Fitzal, Georg Pfeiler, Sophie Frantal, Rupert A. Bartsch, Michael Gnant. Effect of concomitant statin treatment in postmenopausal patients with hormone-receptor positive early-stage breast cancer receiving adjuvant denosumab or placebo: A post-hoc analysis of ABCSG-18 [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-15-01.

The OncoMasTR Test Predicts Distant Recurrence in Estrogen Receptor-Positive, HER2-Negative Early-Stage Breast Cancer: A Validation Study in ABCSG Trial 8.

To validate the clinical performance of the OncoMasTR Risk Score in the biomarker cohort of Austrian Breast and Colorectal Cancer Study Group (ABCSG) Trial 8. We evaluated the OncoMasTR test in 1,200 formalin-fixed, paraffin-embedded (FFPE) surgical specimens from postmenopausal women with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative primary breast cancer with 0 to 3 involved lymph nodes in the prospective, randomized ABCSG Trial 8. Time to distant recurrence (DR) was analyzed by Cox models. The OncoMasTR Risk Score categorized 850 of 1,087 (78.2%) evaluable patients as "low risk". At 10 years, the DR rate for patients in the low-risk group was 5.8% versus 21.1% for patients in the high-risk group (P < 0.0001, absolute risk reduction 15.3%). The OncoMasTR Risk Score was highly prognostic for prediction of DR in years 0 to 10 in all patients [HR 1.91, 95% confidence interval (CI) 1.62-2.26, P < 0.0001; C-index 0.73], in patients that were node negative (HR 1.79, 95% CI, 1.43-2.24, P < 0.0001; C-index 0.72), and in patients with 1 to 3 involved lymph nodes (HR 1.93, 95% CI, 1.44-2.58, P < 0.0001; C-index 0.71). The OncoMasTR Risk Score provided significant additional prognostic information beyond clinical parameters, Ki67, Nottingham Prognostic Index, and Clinical Treatment Score. OncoMasTR Risk Score is highly prognostic for DR in postmenopausal women with ER-positive, HER2-negative primary breast cancer with 0 to 3 involved lymph nodes. In combination with prior validation studies, this fully independent validation in ABCSG Trial 8 provides level 1B evidence for the prognostic capability of the OncoMasTR Risk Score.

ESR1, PGR, ERBB2, and MKi67 mRNA expression in postmenopausal women with hormone receptor-positive early breast cancer: results from ABCSG Trial 6

BackgroundThe purpose of this study was to assess the concordance of real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) detection of ESR1, PGR, ERBB2, and MKi67 messenger RNA (mRNA) in breast cancer tissues with central immunohistochemistry (IHC) in women treated within the prospective, randomized Austrian Breast and Colorectal Cancer Study Group (ABCSG) Trial 6.Patients and methodsWe evaluated ESR1, PGR, ERBB2, and MKi67 mRNA expression by Xpert® Breast Cancer STRAT4 (enables cartridge-based RT-qPCR detection of mRNA in formalin-fixed paraffin-embedded tissues) and estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki67 protein expression by IHC [in situ hybridization (ISH) for HER2 IHC 2+] in 1115 surgical formalin-fixed paraffin-embedded specimens from patients of ABCSG Trial 6. Overall percent agreement (concordance), positive percent agreement (sensitivity), and negative percent agreement (specificity) between STRAT4 and IHC were determined for each marker. The primary objective of the study was concordance between STRAT4 mRNA measurements of ESR1, PGR, ERBB2, and MKi67 with central reference laboratory IHC (and ISH for HER2 IHC 2+ cases). Time to distant recurrence was analyzed by Cox models.ResultsAll performance targets for ER, PR, and Ki67 were met. For HER2, the negative percent agreement target but not the positive percent agreement target was met. Concordance between STRAT4 and IHC was 98.9% for ER, 89.9% for PR, 98.2% for HER2, and 84.8% for Ki67 (excluding intermediate IHC 10%-20% staining). In univariable and multivariable Cox regression analyses, all four biomarkers tested by either STRAT4 RT-qPCR or by central IHC (ISH) had a comparable time to distant recurrence indicating similar prognostic value.ConclusionsWith the exception of HER2, we demonstrate high concordance between centrally assessed IHC and mRNA measurements of ER, PR, and Ki67 as well as a high correlation of the two methods with clinical outcome. Thus, mRNA-based assessment by STRAT4 is a promising new tool for diagnostic and therapeutic decisions in breast cancer.

Influence of Height on Risk and Outcome of Patients with Early Breast Cancer: A Pooled Analysis of 4,925 Patients from 5 Randomized Trials of the Austrian Breast and Colorectal Cancer Study Group (ABCSG)

Background: Associations between height, cancer risk and worse outcome have been reported for several cancers including breast cancer. We hypothesized that in breast cancer clinical trials, tall women should be overrepresented and might have worse prognosis. Methods: Data of 4,935 women, included from 1990 to 2010 in 5 trials of the Austrian Breast and Colorectal Cancer Study Group (ABCSG), were analyzed retrospectively. The primary objective was to determine differences in height distribution between the ABCSG cohort and the Austrian female population according to a cross-sectional health survey conducted by the Austrian Statistic Center in 2006 and 2007. Secondary endpoints were disease-free survival (DFS) and overall survival (OS) in different height classes and differences of body mass index (BMI) distribution. Results: Breast cancer patients in the ABCSG cohort were only slightly but statistically significantly smaller compared to unselected Austrian adult females (mean 164.3 vs. 164.8 cm; p < 0.0001) and significantly more patients were seen in the lower body height class (50 vs. 46%; p < 0.0001) when using the median as a cutoff. However, after adjustment for age, the difference in body height between the two cohorts was no longer significant (p = 0.089). DFS and OS in the two upper height groups (≥170 cm) compared to the two lowest height groups (<160 cm) was not significantly different (5-year DFS: 84.7 vs. 83.0%; HR 0.91, 95% CI 0.73–1.13, p = 0.379; 5-year OS: 94.8 vs. 91.7%; HR 0.74, 95% CI 0.55–1.00, p = 0.051). The BMI of ABCSG patients was significantly higher than in the reference population (mean BMI 24.64 vs. 23.96; p < 0.0001). Conclusions: Our results do not confirm previous findings that greater body height is associated with a higher breast cancer risk and worse outcome.

PAM-50 predicts local recurrence after breast cancer surgery in postmenopausal patients with ER+/HER2- disease: results from 1204 patients in the randomized ABCSG-8 trial.

The aim of this study was to investigate whether the PAM-50-based 46-gene assay carries prognostic value for risk of local recurrence of breast cancer. The Austrian Breast and Colorectal Cancer Study Group (ABCSG) 8 RCT compared 5 years of tamoxifen with tamoxifen for 2 years followed by anastrozole for 3 years in postmenopausal women with endocrine receptor-positive breast cancer. This study included patients from the trial who had breast-conserving surgery for whom tumour blocks were available for PAM-50 analysis. Tumour blocks from 1204 patients who had breast-conserving surgery were available for the PAM-50 analysis, and 1034 of these received radiotherapy. After a median follow-up of 10.8 years, 23 local events had been observed, corresponding to an overall local recurrence risk of 2.2 per cent. Univariable competing-risk analysis demonstrated that patients at low risk according to PAM-50 analysis (risk-of-recurrence (ROR) score less than 57) had a significantly lower incidence of local recurrence than those in the high-risk group at 5 years (0.1 (95 per cent c.i. 0 to 0.7) versus 2.2 (0.9 to 4.6) per cent respectively; subhazard ratio (SHR) 17.18, 95 per cent c.i. 2.06 to 142.88; P = 0.009) and 10 years (0.9 (0.4 to 2.0) versus 3.8 (1.9 to 6.6) per cent; SHR 4.76, 1.72 to 13.17; P = 0.003). Multivariable analyses that included ROR score, age, tumour size, nodal status, type of surgery, tumor grade, and trial-specific endocrine therapy confirmed that ROR score was an independent prognostic factor for risk of local recurrence. Analysis of the women randomized to radiotherapy or control after breast conservation showed that PAM-50 was not predictive of radiotherapy effect. PAM-50 can be used as a prognostic tool for local recurrence risk in postmenopausal women with hormone receptor-positive breast cancer treated with endocrine therapy. The test was not predictive for the benefit of radiotherapy.

Effect of local surgery on outcomes of stage IV breast cancer.

Metastatic breast cancer (MBC), including de novo stage IV, is regarded as being incurable and the mainstay of clinical management is systemic therapy. Traditionally, locoregional surgery is performed only for local control, such as to prevent ulceration and bleeding. In recent years, however, both retrospective and prospective studies have demonstrated the prognostic efficacy of primary surgery for de novo stage IV patients. Therefore, we conducted a meta-analysis to evaluate whether surgical therapy contributes to overall survival (OS) extension. We searched for clinical trials published in electronic databases (PubMed, Embase, and the Cochrane databases) and performed a meta-analysis of the data collected. There were five prospective randomized controlled phase III trials (RCTs). The results of three have been reported. According to our meta-analysis of these RCTs, primary surgery for de novo stage IV breast cancer patients significantly improves OS. However, the Tata trial showed that systemic therapy does not achieve a sufficient effect. Another trial, conducted in Turkey, had statistical shortcomings and patient randomization was not adequately performed The ABCSG (Austrian Breast and Colorectal Cancer Study Group) trial had too few subjects. Meta-analysis of 12 retrospective studies showed that patients with stage IV breast cancer receiving surgery as the initial treatment experienced longer OS (HR: 0.65, P<0.00001). Based on our meta-analysis of three reported RCTs, surgery as the primary treatment does not significantly impact the outcomes of de novo stage IV breast cancer patients. However, these trials had limitations. We await the results of the remaining two ongoing RCTs (ECOG 2108 and JCOG 1017). These trials are anticipated to resolve current controversies and provide many eagerly awaited answers.

Patterns of care in metastatic pancreatic cancer: patient selection in clinical routine.

Background:The management of patients with metastatic pancreatic cancer (mPC) is challenging, and the optimal treatment strategy is debated among experts. In an attempt to identify treatment decision criteria and to investigate variations in the first-line management of this disease, we performed an analysis of treatment algorithms among experts in the field of pancreatic cancer. The aim of this study was to identify relevant criteria in the complex process of patient selection and decision making for the management of mPC patients.Methods:Experts from the ABCSG (Austrian Breast and Colorectal Cancer Study Group) Pancreatic Cancer Club were contacted and agreed to participate in this analysis. Eight experts from seven centers in Austria provided their decision algorithms for the first-line treatment of patients with mPC. Their responses were converted into decision trees based on the objective consensus methodology. The decision trees were used to identify consensus and discrepancies.Results:The final treatment algorithms included four decision criteria (performance status, age, comorbidities, and symptomatic disease) and six treatment options: mFOLFIRINOX, gemcitabine + nab-paclitaxel, gemcitabine mono, 5-FU mono, gemcitabine/erlotinib, and best supportive care (BSC).Conclusions:We identified consensus for the treatment of young and fit patients with mFOLFIRINOX. With higher age and reduced performance status, gemcitabine + nab-paclitaxel was increasingly used. For patients with Eastern Co-operative Oncology Group Performance Status (ECOG PS) 4, BSC was the treatment of choice. Among experts, different decision criteria and treatment options are implemented in clinical routine. Despite multiple options in current recommendations, a consensus for specific recommendations was identified.

Abstract P1-08-13: Predictive value of intrinsic luminal subtypes in premenopausal women with endocrine-responsive early breast cancer: Results from Austrian breast and colorectal cancer study group trial 5

Abstract Purpose: The aim of the present study was to assess the predictive value of intrinsic luminal subtypes in premenopausal hormone receptor-positive early breast cancer patients who received adjuvant endocrine treatment or chemotherapy. Patients and Methods: Intrinsic luminal breast cancer subtypes were centrally assessed by immunohistochemistry on whole tissue sections of breast cancer patients who had been enrolled in the Austrian Breast and Colorectal Cancer Study Group (ABCSG) Trial 5 and received either 3 years of goserelin plus 5 years of tamoxifen or six cycles of cyclophosphamide, methotrexate, and fluorouracil (CMF). Luminal A disease was defined as Ki67 &amp;lt;20%, Luminal B/HER2-negative subtype as Ki67≥20%. Luminal B/HER2-positive subtype displayed HER2 overexpression by IHC or amplification by ISH. Recurrence-free survival (RFS) and overall survival (OS) were analyzed using Cox models adjusted for clinical and pathological factors. Results: 155 (36%), 217 (50%) and 59 (14%) of 431 tumors were classified as Luminal A, Luminal B/HER2-negative and Luminal B/HER2-positive, respectively. Luminal B subtypes were associated with poor outcome. Patients with Luminal B tumors had a significantly shorter RFS (adjusted hazard ratio [HR] for recurrence: 2.29, 95% confidence interval [CI] 1.44-3.64, P &amp;lt; 0.001) and OS (adjusted HR for death: 3.97, 95% CI 1.94-8.08, P &amp;lt; 0.001) as compared to patients with Luminal A disease. No interaction between intrinsic luminal subtypes and treatment was observed (test for interaction: P = 0.42 for RFS; P = 0.32 for OS). Combination endocrine treatment with goserelin/tamoxifen tended to be more effective than CMF chemotherapy in both luminal A and luminal B subtypes. Conclusion: Intrinsic luminal subtype is an independent prognostic factor for recurrence and death in premenopausal women with early-stage, hormone receptor positive breast cancer but is not predictive for outcome of adjuvant treatment with either goserelin/tamoxifen or chemotherapy with CMF. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-13.

Bisphosphonates and Breast Cancer Prevention

Bisphosphonates are commonly used in patients with breast cancer to reduce skeletal-related events in metastatic disease and to mitigate bone loss associated with cancer therapy in early stage disease. In addition, adjuvant breast cancer trials evaluating the oral bisphosphonate clodronate suggested a reduction in cancer recurrence, but the findings were mixed, with 2 positive and 1 negative report. In the Austrian Breast and Colorectal Cancer Study Group (ABCSG) 12 study, adding the intravenous bisphosphonate zoledronic acid to endocrine therapy in premenopausal breast cancer patients significantly prolonged disease-free survival versus endocrine therapy alone (hazard ratio = 0.68; p = 0.008) at 62 months, and reduced local, regional, and distant recurrences. Clinical trial findings from other adjuvant trials (Z-FAST, ZO-FAST), neoadjuvant studies, and studies involving disseminated tumor cells (DTCs) are generally supportive of the ABCSG-12 conclusion, and recent data from AZURE suggest the importance of menopausal status. Preclinical studies provide data on the mechanisms of action that could mediate bisphosphonate direct and indirect anti-cancer effects. Recently, several observational studies (2 cohort studies and 2 case-control analyses) have associated oral bisphosphonate use with a lower breast cancer incidence. Such reports require cautious interpretation because confounding by indication is an issue: bisphosphonates are prescribed for women with low bone mineral density, and women with low bone density are at decreased breast cancer risk.

Neoadjuvant Clinical Trials for the Treatment of Primary Breast Cancer: The Experience of the German Study Groups

The advantages of neoadjuvant chemotherapy are the ability to 1) increase the rate of breast conservation and improve operability, 2) to reduce mortality by recognizing resistance mechanisms early, and 3) to investigate the activity of new agents by assessing the pathological complete response rate as a surrogate marker for clinical efficacy. The German Breast Group (GBG) is a cooperative study group which focuses on neoadjuvant therapy for breast cancer. This group cooperates closely with the German Gynecological Oncology Working Group-Breast (AGO-B). Additionally, these two German study groups maintain close ties with other national and international study groups, such as the Breast International Group (BIG), Austrian Breast and Colorectal Cancer Study Group (ABCSG), Central European Cooperative Oncology Group (CECOG), International Cooperative Cancer Group (ICCG) and National Surgical Adjuvant Breast Project (NSABP). A series of clinical trials evaluating the role of neoadjuvant therapy in women with primary breast cancer have been designed, performed and published over the last 10 years. This article summarizes the results of the neoadjuvant trials that have been conducted by the German study groups, outlines ongoing clinical research projects, and discusses concepts for future clinical trials.

Prognostic Value of Number of Removed Lymph Nodes, Number of Involved Lymph Nodes, and Lymph Node Ratio in 7502 Breast Cancer Patients Enrolled onto Trials of the Austrian Breast and Colorectal Cancer Study Group (ABCSG)

The number of removed axillary lymph nodes and the ratio of involved to removed lymph nodes are described as independent prognostic factors beside the absolute number of involved lymph nodes in breast cancer patients. The correlation between these factors and prognosis were investigated in trials of the Austrian Breast and Colorectal Cancer Study Group (ABCSG). This retrospective analysis is based on the data of 7052 patients with endocrine-responsive breast cancer who were randomized in four trials of the ABCSG in the years 1990-2006 and underwent axillary lymph node dissection. The prognostic value of number of removed nodes (NRN), number of involved nodes (NIN), and ratio of involved to removed nodes (lymph node ratio, LNR) concerning recurrence-free survival and overall survival was analyzed. A total of 2718 patients had node-positive disease. No correlation was found between NRN and prognosis. Increasing NIN and LNR were significantly associated with worse recurrence-free survival and overall survival in univariate and multivariate analyses (P < .001). Only in the subgroup of patients with one to three positive lymph nodes and treated with mastectomy (n = 728) was LNR an additional prognostic factor in univariate and multivariate analyses. For breast cancer patients stringently medicated in the framework of prospective adjuvant clinical trials and requiring a mandatory minimum of removed nodes, NRN does not influence prognosis, and LNR is not superior to NIN as prognostic factor. In patients with one to three positive lymph nodes and mastectomy, LNR could play a role as an additional prognostic factor.

A New Molecular Predictor of Distant Recurrence in ER-Positive, HER2-Negative Breast Cancer Adds Independent Information to Conventional Clinical Risk Factors

According to current guidelines, molecular tests predicting the outcome of breast cancer patients can be used to assist in making treatment decisions after consideration of conventional markers. We developed and validated a gene expression signature predicting the likelihood of distant recurrence in patients with estrogen receptor (ER)-positive, HER2-negative breast cancer treated with adjuvant endocrine therapy. RNA levels assessed by quantitative reverse transcriptase PCR in formalin-fixed, paraffin-embedded tumor tissue were used to calculate a risk score (Endopredict, EP) consisting of eight cancer-related and three reference genes. EP was combined with nodal status and tumor size into a comprehensive risk score, EPclin. Both prespecified risk scores including cutoff values to determine a risk group for each patient (low and high) were validated independently in patients from two large randomized phase III trials [Austrian Breast and Colorectal Cancer Study Group (ABCSG)-6: n = 378, ABCSG-8: n = 1,324]. In both validation cohorts, continuous EP was an independent predictor of distant recurrence in multivariate analysis (ABCSG-6: P = 0.010, ABCSG-8: P < 0.001). Combining Adjuvant!Online, quantitative ER, Ki67, and treatment with EP yielded a prognostic power significantly superior to the clinicopathologic factors alone [c-indices: 0.764 vs. 0.750, P = 0.024 (ABCSG-6) and 0.726 vs. 0.701, P = 0.003 (ABCSG-8)]. EPclin had c-indices of 0.788 and 0.732 and resulted in 10-year distant recurrence rates of 4% and 4% in EPclin low-risk and 28% and 22% in EPclin high-risk patients in ABCSG-6 (P < 0.001) and ABCSG-8 (P < 0.001), respectively. The multigene EP risk score provided additional prognostic information to the risk of distant recurrence of breast cancer patients, independent from clinicopathologic parameters. The EPclin score outperformed all conventional clinicopathologic risk factors.

Impact of Body Mass Index on the Efficacy of Endocrine Therapy in Premenopausal Patients With Breast Cancer: An Analysis of the Prospective ABCSG-12 Trial

Aromatase inhibitors are effective as endocrine treatment for patients with hormone receptor-positive breast cancer. According to the hypothesis that overweight patients have higher levels of aromatase enzyme availability, we investigated the influence of body mass index (BMI) on the efficacy of adjuvant endocrine therapy in premenopausal patients in a retrospective analysis of the Austrian Breast and Colorectal Cancer Study Group (ABCSG) 12 trial. ABCSG-12 examined the efficacy of ovarian suppression using goserelin (3.6 mg subcutaneously every 28 days) in combination with anastrozole or tamoxifen with or without zoledronic acid (4 mg intravenously every 6 months) in premenopausal women with endocrine-responsive breast cancer. BMI was calculated using the prospectively collected data on patients' height and weight at study entry. BMI categories have been differentiated according to the WHO definition. Overweight patients treated with anastrozole had a 60% increase in the risk of disease recurrence (hazard ratio [HR], 1.60; 95% CI, 1.06 to 2.41; P = .02) and more than a doubling in the risk of death (HR, 2.14; 95% CI, 1.17 to 3.92; P = .01) compared with normal weight patients treated with anastrozole. In the overweight group, patients treated with anastrozole had a nearly 50% increase in the risk of disease recurrence (HR, 1.49; 95% CI, 0.93 to 2.38; P = .08) and a three-fold increase in the risk of death (HR, 3.03; 95% CI, 1.35 to 6.82; P = .004) compared with patients treated with tamoxifen. BMI significantly impacts on the efficacy of anastrozole plus goserelin in premenopausal patients with breast cancer, probably through influencing aromatase availability and/or ovarian suppression by goserelin.

Sentinel Node Biopsy After Primary Chemotherapy in Breast Cancer: A Note of Caution from Results of ABCSG-14

Over the past years, experience has been increasing with lymphatic mapping and sentinel node biopsy (SNB) after preoperative chemotherapy for breast cancer, with a wide range of results reported in the literature and final conclusions on the diagnostic value and clinical consequences of this sequential approach still missing. Between 1999 and 2002, the Austrian Breast and Colorectal Cancer Study Group (ABCSG) conducted a prospective randomized multicenter trial comparing three versus six preoperative cycles of epirubicin/docetaxel + granulocyte colony-stimulating factor for operable breast cancer. Of the 292 patients recruited to the trial overall, 111 were enrolled in a prospective subprotocol for performing LM and SNB in addition to obligatory axillary lymph node dissection (ALND) after PC. SNB after PC identified at least one sentinel node in 100 of 111 patients (identification rate 90%). In six cases, a false-negative SN was identified, resulting in a false-negative rate of 13% (6 of 47). We only found little correlation between patients and tumor characteristics and the identification rate or false-negative rate. Lymphatic mapping and SNB after primary chemotherapy failed to predict histologic infiltration of the sentinel node with sufficient sensitivity. The routine use of SNB after primary chemotherapy should therefore be discouraged.

Abstract P4-09-02: Prognostic and Predictive Value of Centrally Reviewed Ki67 Labeling Index in Postmenopausal Women with Endocrine-Responsive Breast Cancer: Results from Austrian Breast and Colorectal Cancer Study Group Trial 8

Abstract Purpose: The aim of the present study was to assess the prognostic and predictive value of Ki67 labeling index in postmenopausal hormone receptor-positive early breast cancer patients who were treated with adjuvant tamoxifen or anastrozole after tamoxifen. Patients and Methods: We determined the expression of Ki67 by immunohistochemistry on whole tissue sections of breast carcinoma patients who had been enrolled in Austrian Breast and Colorectal Cancer Study Group (ABCSG) Trial 8 and received tamoxifen for 5 years or tamoxifen for 2 years followed by anastrozole for 3 years. Ki67 labeling index was evaluated as continuous variable or dichotomized at 10%. Distant recurrence and death were analyzed using Cox models adjusted for clinical and pathological factors. Results: High Ki67 labeling index was observed in 394 of 1587 (23%) tumors and was associated with poor outcome. Patients with high Ki67 labeling index had a significantly shorter distant recurrence-free survival (adjusted hazard ratio [HR] for distant recurrence 2.16, 95% confidence interval [CI] 1.43-3.25, P &amp;lt; 0.001) and overall survival (adjusted HR for death 1.77, 95% CI 1.30-2.42, P &amp;lt; 0.001) as compared to patients with low Ki67 labeling index. No interaction between Ki67 labeling index and treatment was observed (P = 0.84). Conclusion: High Ki67 labeling index is an independent poor prognostic factor for distant recurrence and death in postmenopausal women with early-stage, hormone receptor-positive breast cancer but is not predictive for outcome of adjuvant treatment with either tamoxifen or tamoxifen followed by anastrozole. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-09-02.

Two years of tamoxifen followed by 3 years of anastrozole versus 5 years of tamoxifen alone in postmenopausal women with hormone-responsive early breast cancer: Efficacy results from 3,714 patients from the Austrian Breast and Colorectal Cancer Study Group (ABCSG) trial 8.

534 Background: Anastrozole (ANA) alone delivers significant DFS benefits over tamoxifen (TAM) therapy in postmenopausal women with early ER+ breast cancer. Limited data have been published concern...

Is long-term adjuvant treatment of breast cancer with anastrozole indicated?

Background: Tamoxifen is the established adjuvant treatment for postmenopausal women with hormone-sensitive breast cancer. Objective: To determine whether the aromatase inhibitor anastrozole should replace tamoxifen as the adjuvant treatment in this cancer. Methods: Two recent trials of anastrozole and tamoxifen as adjuvant treatment were evaluated. Results/conclusion: The Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial showed that 5 years of adjuvant therapy with anastrozole reduced recurrence of breast cancer to a greater extent than did tamoxifen. The Austrian Breast and Colorectal Cancer Study Group (ABCSG) Trial 6a showed that after 5 years of adjuvant treatment with tamoxifen more benefit was achieved by continuing with adjuvant anastrozole for 3 years than no further treatment. Although the long-term adjuvant treatment of hormone receptor positive breast cancer with anastrozole is indicated, questions remain as to how long the adjuvant treatment with anastrozole should continue.

Cyclin D1 Expression in Breast Cancer Patients Receiving Adjuvant Tamoxifen-Based Therapy

The objective of our study was to determine the clinical relevance of cyclin D1 expression in hormone receptor-positive breast cancer patients who were treated with tamoxifen-based therapy. We assessed expression of cyclin D1 in surgical specimens of breast carcinoma by means of immunohistochemistry. Patients had been enrolled in either Austrian Breast and Colorectal Cancer Study Group (ABCSG) Trial 05 or ABCSG Trial 06 and received tamoxifen as part of their adjuvant treatment. Overall survival and relapse-free survival were analyzed with Cox models adjusted for clinical and pathologic factors. Cyclin D1 was expressed in 140 of 253 (55%) tumors of ABCSG Trial 05 and in 569 of 948 (60%) tumors of ABCSG Trial 06. Expression of cyclin D1 was associated with poor outcome in both cohorts. Overall survival was significantly shorter in patients with cyclin D1-positive tumors compared with patients with cyclin D1-negative tumors [adjusted hazard ratio (HR) for death (ABCSG Trial 05), 2.47; 95% confidence interval (95% CI), 1.08-5.63; P = 0.03; adjusted HR for death (ABCSG Trial 06), 1.78; 95% CI, 1.36-2.34; P < 0.0001]. Relapse-free survival was also shorter in patients with cyclin D1-positive tumors than in patients with cyclin D1-negative tumors [adjusted HR for relapse (ABCSG Trial 05), 2.73; 95% CI, 1.50-4.96; P = 0.001; adjusted HR for relapse (ABCSG Trial 06), 1.52; 95% CI, 1.14-2.04; P = 0.005]. Cyclin D1 expression is an independent poor prognostic factor in women with early-stage, hormone receptor-positive breast cancer who received adjuvant tamoxifen-based therapy.

Extended Adjuvant Therapy With Anastrozole Among Postmenopausal Breast Cancer Patients: Results From the Randomized Austrian Breast and Colorectal Cancer Study Group Trial 6a

Clinical trial data have shown that among breast cancer patients who were disease free after 5 years of adjuvant treatment with tamoxifen, further extended treatment with the nonsteroidal aromatase inhibitor letrozole reduces breast cancer recurrence. We examined the efficacy and tolerability of extended adjuvant therapy with another aromatase inhibitor, anastrozole, for 3 years among women who had completed 5 years of adjuvant therapy. Austrian Breast and Colorectal Cancer Study Group (ABCSG) Trial 6a is an extension of ABCSG Trial 6, in which hormone receptor-positive postmenopausal patients received 5 years of adjuvant tamoxifen, with or without the aromatase inhibitor aminoglutethimide, for the first 2 years of therapy. For ABCSG Trial 6a, patients who were disease free at the end of Trial 6 were randomly assigned to receive either 3 years of anastrozole or no further treatment. Efficacy data were analyzed with the use of a Cox proportional hazards regression model with two-sided P values and Kaplan-Meier curves, and tolerability data were estimated using logistic regression analysis with odds ratios and 95% confidence intervals (CIs). ABCSG Trial 6a included 856 patients. At a median follow-up of 62.3 months, women who received anastrozole (n = 387) had a statistically significantly reduced risk of recurrence (locoregional recurrence, contralateral breast cancer, or distant metastasis) compared with women who received no further treatment (n = 469; hazard ratio = 0.62; 95% CI = 0.40 to 0.96, P = .031). Anastrozole was well tolerated, and no unexpected adverse events were reported. These data confirm the benefit of extending adjuvant tamoxifen therapy beyond 5 years with anastrozole compared with no further treatment. Further research is required to define the optimum length of extended adjuvant therapy and to investigate the possibility of tailoring this period to suit different disease types.