Discordance between Immunohistochemistry and Erb-B2 Receptor Tyrosine Kinase 2 mRNA to Determine Human Epidermal Growth Factor Receptor 2 Low Status for Breast Cancer.

Novel human epidermal growth factor receptor 2 (HER2)-directed antibody-drug conjugates have demonstrated efficacy in HER2-low expressing breast cancers, which are currently defined as those with immunohistochemistry (IHC) scores of 1+ or 2+ with a negative in situ hybridization assay. However, current HER2 testing methods are designed to identify HER2-amplified tumors with high expression levels. The true definition of HER2-low expressing breast cancers remains controversial. Using quantitative molecular analysis of breast cancers based on RNA expression, the dynamic range of HER2 expression exceeds that detected by in situ IHC approaches. Erb-B2 receptor tyrosine kinase 2 (ERBB2) mRNA expression levels across IHC groups using patient samples derived from the Tamoxifen Exemestane Adjuvant Multicenter Trial were investigated. The standardized mean differences in ERBB2 mRNA scores in log base 2 are 0.47 (95% CI, 0.36-0.57), 0.58 (95% CI, 0.26-0.70), and 0.32 (95% CI, -0.12 to 0.75) when comparing IHC 0+ without staining versus IHC 0+ with some staining, IHC 0+ with some staining versus IHC 1+, and IHC 1+ versus IHC 2+/fluorescence in situ hybridization-negative, respectively. The results showed immunohistochemical methods have a comparatively limited dynamic range for measuring HER2 protein expression. The range of expression based on RNA abundance suggests a molecular method defining HER2-low cancers may better serve the treatment decision needs of this group. Indeed, the validity of RNA abundance to identify HER2-low cancers and predict treatment response needs to be further evaluated by prospective clinical trials.

Synchronous versus sequential chemo-radiotherapy in patients with early stage breast cancer (SECRAB): A randomised, phase III, trial.

BACKGROUND: The optimal sequence of adjuvant chemotherapy and radiotherapy for breast cancer is unknown. SECRAB assesses whether local control can be improved without increased toxicity. METHODS: SECRAB was a prospective, open-label, multi-centre, phase III trial comparing synchronous to sequential chemo-radiotherapy, conducted in 48 UK centres. Patients with invasive, early stage breast cancer were eligible. Randomisation (performed using random permuted block assignment) was stratified by centre, axillary surgery, chemotherapy, and radiotherapy boost. Permitted chemotherapy regimens included CMF and anthracycline-CMF. Synchronous radiotherapy was administered between cycles two and three for CMF or five and six for anthracycline-CMF. Sequential radiotherapy was delivered on chemotherapy completion. Radiotherapy schedules included 40 Gy/15F over three weeks, and 50 Gy/25F over five weeks. The primary outcome was local recurrence at five and ten years, defined as time to local recurrence, and analysed by intention to treat. ClinicalTrials.gov NCT00003893. FINDINGS: Between 02-July-1998 and 25-March-2004, 2297 patients were recruited (1150 synchronous and 1146 sequential). Baseline characteristics were balanced. With 10.2 years median follow-up, the ten-year local recurrence rates were 4.6% and 7.1% in the synchronous and sequential arms respectively (hazard ratio (HR) 0.62; 95% confidence interval (CI): 0.43-0.90; p = 0.012). In a planned sub-group analysis of anthracycline-CMF, the ten-year local recurrence rates difference were 3.5% versus 6.7% respectively (HR 0.48 95% CI: 0.26-0.88; p = 0.018). There was no significant difference in overall or disease-free survival. 24% of patients on the synchronous arm suffered moderate/severe acute skin reactions compared to 15% on the sequential arm (p < 0.0001). There were no significant differences in late adverse effects apart from telangiectasia (p = 0.03). INTERPRETATION: Synchronous chemo-radiotherapy significantly improved local recurrence rates. This was delivered with an acceptable increase in acute toxicity. The greatest benefit of synchronous chemo-radiation was in patients treated with anthracycline-CMF. FUNDING: Cancer Research UK (CR UK/98/001) and Pharmacia.

Predicting Anthracycline Benefit: TOP2A and CEP17-Not Only but Also.

PURPOSE: Evidence supporting the clinical utility of predictive biomarkers of anthracycline activity is weak, with a recent meta-analysis failing to provide strong evidence for either HER2 or TOP2A. Having previously shown that duplication of chromosome 17 pericentromeric alpha satellite as measured with a centromere enumeration probe (CEP17) predicted sensitivity to anthracyclines, we report here an individual patient-level pooled analysis of data from five trials comparing anthracycline-based chemotherapy with CMF (cyclophosphamide, methotrexate, and fluorouracil) as adjuvant chemotherapy for early breast cancer. PATIENTS AND METHODS: Fluorescent in situ hybridization for CEP17, HER2, and TOP2A was performed in three laboratories on samples from 3,846 of 4,864 eligible patients from five trials evaluating anthracycline-containing chemotherapy versus CMF. Methodologic differences did not affect HER2-to-CEP17 ratios but necessitated different definitions for CEP17 duplication: > 1.86 observed copies per cell for BR9601, NEAT, Belgian, and DBCG89D trials and > 2.25 for the MA.5 trial. RESULTS: Fluorescent in situ hybridization data were available in 89.3% (HER2), 83.9% (CEP17), and 80.6% (TOP2A) of 3,846 patient cases with available tissue. Both CEP17and TOP2A treatment-by-marker interactions remained significant in adjusted analyses for recurrence-free and overall survival, whereas HER2 did not. A combined CEP17 and TOP2A-adjusted model predicted anthracycline benefit across all five trials for both recurrence-free (hazard ratio, 0.64; 95% CI, 0.51 to 0.82; P = .001) and overall survival (hazard ratio, 0.66; 95% CI, 0.51 to 0.85; P = .005). CONCLUSION: This prospectively planned individual-patient pooled analysis of patient cases from five adjuvant trials confirms that patients whose tumors harbor either CEP17 duplication or TOP2A aberrations, but not HER2 amplification, benefit from adjuvant anthracycline chemotherapy.

Epirubicin and cyclophosphamide, methotrexate, and fluorouracil as adjuvant therapy for early breast cancer.

BACKGROUND: The National Epirubicin Adjuvant Trial (NEAT) and the BR9601 trial examined the efficacy of anthracyclines in the adjuvant treatment of early breast cancer. METHODS: In NEAT, we compared four cycles of epirubicin followed by four cycles of cyclophosphamide, methotrexate, and fluorouracil (CMF) with six cycles of CMF alone. In the BR9601 trial, we compared four cycles of epirubicin followed by four cycles of CMF, with eight cycles of CMF alone every 3 weeks. The primary end points were relapse-free and overall survival. The secondary end points were adverse effects, dose intensity, and quality of life. RESULTS: The two trials included 2391 women with early breast cancer; the median follow-up was 48 months. Relapse-free and overall survival rates were significantly higher in the epirubicin-CMF groups than in the CMF-alone groups (2-year relapse-free survival, 91% vs. 85%; 5-year relapse-free survival, 76% vs. 69%; 2-year overall survival, 95% vs. 92%; 5-year overall survival, 82% vs. 75%; P<0.001 by the log-rank test for all comparisons). Hazard ratios for relapse (or death without relapse) (0.69; 95% confidence interval [CI], 0.58 to 0.82; P<0.001) and death from any cause (0.67; 95% CI, 0.55 to 0.82; P<0.001) favored epirubicin plus CMF over CMF alone. Independent prognostic factors were nodal status, tumor grade, tumor size, and estrogen-receptor status (P<0.001 for all four factors) and the presence or absence of vascular or lymphatic invasion (P=0.01). These factors did not significantly interact with the effect of epirubicin plus CMF. The overall incidence of adverse effects was significantly higher with epirubicin plus CMF than with CMF alone but did not significantly affect the delivered-dose intensity or the quality of life. CONCLUSIONS: Epirubicin plus CMF is superior to CMF alone as adjuvant treatment for early breast cancer. (ClinicalTrials.gov number, NCT00003577 [ClinicalTrials.gov].).

Endocrine therapy and other targeted therapies for metastatic breast cancer.

The most important change in the treatment of advanced breast cancer that will emerge over the next 10 years is the shift from adjuvant tamoxifen to adjuvant aromatase inhibitors. This will mean an increasing proportion of tamoxifen-naive aromatase inhibitor-resistant breast cancer. Research of the most appropriate methods of optimizing remaining endocrine sensitivity in these patients is needed. The rapid expansion in the understanding of the molecular basis of breast cancer biology provides potential targets for novel therapies. Despite these pivotal developments, resistance to endocrine therapy remains a key limitation in the management of advanced breast cancer. Until recently, the only option following the development of resistance to an endocrine agent was to change endocrine therapy and, on exhaustion of endocrine sensitivity, to move to cytotoxic chemotherapy. Understanding of at least some of the mechanisms underlying the development of endocrine resistance is now emerging. We now have the tools that may allow us to both overcome resistance and restore sensitivity, or to pre-empt certain types of resistance from developing. These tools include the increasing array of signal transduction inhibitors in combination with standard endocrine agents. Correct clinical management strategy can be guided by preclinical modeling but can only be validated by carefully designed clinical trials. These will, at the very least, need to be conducted with correlative translational research elements that will track changes in tumors as resistance emerges and will allow us to select the most appropriate treatment strategy for individual patients. Amongst the myriad of promising drugs there will undoubtedly be some that fail to meet current hopes, but we can be optimistic that a handful will find a useful place in keeping advanced breast cancer at bay for longer than can be achieved at present. However, the holy grail of a cure is likely, in the medium term, to remain elusively at the end of the rainbow for most of these patients. Several other methods for the management of these patients are in development. These include strategies to overcome endocrine resistance and methods to target deregulated endocrine and growth factor signaling pathways using gene and immunotherapy approaches.