S. Mook

Clinical Application of the 70-Gene Profile: The MINDACT Trial

The 70-gene profile is a new prognostic tool that has the potential to greatly improve risk assessment and treatment decision making for early breast cancer. Its prospective validation is currently ongoing through the MINDACT (Microarray in Node-Negative Disease May Avoid Chemotherapy) trial, a 6,000-patient randomized, multicentric trial. This article reviews the several steps in the development of the profile from its discovery to its clinical validation.

Gene signature evaluation as a prognostic tool: challenges in the design of the MINDACT trial.

This Review describes the work conducted by the TRANSBIG consortium in the development of the MINDACT (Microarray In Node negative Disease may Avoid ChemoTherapy) trial. The goal of the trial is to provide definitive evidence regarding the clinical relevance of the 70-gene prognosis signature, and to assess the performance of this signature compared with that of traditional prognostic indicators for assigning adjuvant chemotherapy to patients with node-negative breast cancer. We outline the background work and the key questions in node-negative early-stage breast cancer, and then focus on the MINDACT trial design and statistical considerations. The challenges inherent in this trial in terms of logistics, implementation and interpretation of the results are also discussed. We hope that this article will trigger further discussion about the difficulties of setting up and analyzing trials aimed at establishing the worth of new methods for better selection of patients for cancer treatment.

The 70-gene prognosis signature predicts early metastasis in breast cancer patients between 55 and 70 years of age

BACKGROUND The majority of breast cancer patients are postmenopausal women who are increasingly being offered adjuvant chemotherapy. Since the beneficial effect of chemotherapy in postmenopausal patients predominantly occurs in the first 5 years after diagnosis, a prognostic marker for early events can be of use for adjuvant treatment decision making. The aim of this study was to evaluate the prognostic value of the 70-gene prognosis signature for early events in postmenopausal patients. METHODS Frozen tumor samples from 148 patients aged 55-70 years were selected (T1-2, N0) and classified by the 70-gene prognosis signature (MammaPrint) into good or poor prognosis. Eighteen percent received hormonal therapy. RESULTS Breast cancer-specific survival (BCSS) at 5 years was 99% for the good-prognosis signature versus 80% for the poor-prognosis signature group (P = 0.036). The 70-gene prognosis signature was a significant and independent predictor of BCCS during the first 5 years of follow-up with an adjusted hazard ratio of 14.4 (95% confidence interval 1.7-122.2; P = 0.01) at 5 years. CONCLUSION The 70-gene prognosis signature can accurately select postmenopausal patients at low risk of breast cancer-related death within 5 years of diagnosis and can be of clinical use in selecting postmenopausal women for adjuvant chemotherapy.

A comprehensive analysis of prognostic signatures reveals the high predictive capacity of the Proliferation, Immune response and RNA splicing modules in breast cancer

IntroductionSeveral gene expression signatures have been proposed and demonstrated to be predictive of outcome in breast cancer. In the present article we address the following issues: Do these signatures perform similarly? Are there (common) molecular processes reported by these signatures? Can better prognostic predictors be constructed based on these identified molecular processes?MethodsWe performed a comprehensive analysis of the performance of nine gene expression signatures on seven different breast cancer datasets. To better characterize the functional processes associated with these signatures, we enlarged each signature by including all probes with a significant correlation to at least one of the genes in the original signature. The enrichment of functional groups was assessed using four ontology databases.ResultsThe classification performance of the nine gene expression signatures is very similar in terms of assigning a sample to either a poor outcome group or a good outcome group. Nevertheless the concordance in classification at the sample level is low, with only 50% of the breast cancer samples classified in the same outcome group by all classifiers. The predictive accuracy decreases with the number of poor outcome assignments given to a sample. The best classification performance was obtained for the group of patients with only good outcome assignments. Enrichment analysis of the enlarged signatures revealed 11 functional modules with prognostic ability. The combination of the RNA-splicing and immune modules resulted in a classifier with high prognostic performance on an independent validation set.ConclusionsThe study revealed that the nine signatures perform similarly but exhibit a large degree of discordance in prognostic group assignment. Functional analyses indicate that proliferation is a common cellular process, but that other functional categories are also enriched and show independent prognostic ability. We provide new evidence of the potentially promising prognostic impact of immunity and RNA-splicing processes in breast cancer.

Calibration and discriminatory accuracy of prognosis calculation for breast cancer with the online Adjuvant! program: a hospital-based retrospective cohort study

BACKGROUND Adjuvant! is a web-based program that calculates individualised 10-year survival probabilities and predicted benefit of adjuvant systemic therapy. The Adjuvant! model has not been validated in any large European series. The aim of our study was to validate Adjuvant! in Dutch patients, investigating both its calibration and discriminatory accuracy. METHODS Patients who were at least partly treated at the Netherlands Cancer Institute for breast cancer between 1987 and 1998 were included if they met the following criteria: tumour size T1 (< or =2 cm), T2 (2-5 cm), or T3 (>5 cm), invasive breast carcinoma, with information about involvement of axillary lymph nodes available, no distant metastases, primary surgery, axillary staging, and radiotherapy according to national guidelines. Clinicopathological characteristics and adjuvant treatment data were retrieved from hospital records and medical registries and were entered into the Adjuvant! (version 8.0) batch processor with blinding to outcome. Endpoints were overall survival and the proportion of patients that did not die from breast cancer (breast-cancer-specific survival [BCSS]). FINDINGS 5380 patients were included with median follow-up of 11.7 years (range 0.03-21.8). The 10-year observed overall survival (69.0%) and BCSS (78.6%) and Adjuvant! predicted overall survival (69.1%) and BCSS (77.8%) were not statistically different (p=0.87 and p=0.18, respectively). Moreover, differences between predicted and observed outcomes were within 2% for most relevant clinicopathological subgroups. In patients younger than 40 years, Adjuvant! overestimated overall survival by 4.2% (p=0.04) and BCSS by 4.7% (p=0.01). The concordance index, which indicates discriminatory accuracy at the individual level, was 0.71 for BCSS in the entire cohort. INTERPRETATION Adjuvant! accurately predicted 10-year outcomes in this large-scale Dutch validation study and is of use for adjuvant treatment decision making, although the results may be less reliable in some subgroups.

Independent Prognostic Value of Screen Detection in Invasive Breast Cancer

BACKGROUND Mammographic screening has led to a proportional shift toward earlier-stage breast cancers at presentation. We assessed whether the method of detection provides prognostic information above and beyond standard prognostic factors and investigated the accuracy of predicted overall and breast cancer-specific survival by the computer tool Adjuvant! among patients with screen-detected, interval, and nonscreening-related carcinomas. METHODS We studied 2592 patients with invasive breast cancer who were treated at the Netherlands Cancer Institute from January 1, 1990, through December 31, 2000. Overall and breast cancer-specific survival probabilities among patients with mammographically screen-detected (n = 958), interval (n = 417), and nonscreening-related (n = 1217) breast carcinomas were compared. Analyses were adjusted for clinicopathologic characteristics and adjuvant systemic therapy. Because of gradual implementation of population-based screening in the Netherlands, analyses were stratified a priori according to two periods of diagnosis. All statistical tests were two-sided. RESULTS Screen detection was associated with reduced mortality (adjusted hazard ratio for all-cause mortality = 0.74, 95% confidence interval = 0.63 to 0.87, P < .001, and adjusted hazard ratio for breast cancer-specific mortality = 0.62, 95% confidence interval = 0.50 to 0.78, P < .001, respectively) compared with nonscreening-related detection. The absolute adjusted reduction in breast cancer-specific mortality was 7% at 10 years. The prognostic value of the method of detection was independent of the period of diagnosis and was similar across tumor size and lymph node status categories, indicating its prognostic value beyond stage migration. Adjuvant! underestimated breast cancer-specific survival in patients with screen-detected (-3.2%) and interval carcinomas (-5.4%). CONCLUSIONS Screen detection was found to be independently associated with better prognosis for overall and breast cancer-specific survival and to provide prognostic information beyond stage migration among patients with invasive breast cancer. We propose that the method of detection should be taken into account when estimating individual prognosis.

Daily clinical practice of fresh tumour tissue freezing and gene expression profiling; logistics pilot study preceding the MINDACT trial

PURPOSE The 70-gene prognosis-signature is a prognostic tool for early breast cancer analysis. In addition to scientific evidence, implementation of the signature in clinical trials and daily practice requires logistical feasibility. The aim of our study was to test logistics for gene expression profiling on fresh frozen tumour tissue in the preparation for the prospective, multinational Microarray In Node-negative Disease may Avoid ChemoTherapy (MINDACT) trial. METHODS Sixty-four patients were included in six European hospitals. Fresh frozen tumour samples were shipped on dry ice to Agendia B.V., where RNA was isolated and subsequently hybridised on the 70-gene prognosis-signature (MammaPrint). RESULTS Tumour samples were obtained in 60 of 64 patients. Among the 60 samples, 11 contained insufficient tumour cells (<50%) and three contained insufficient RNA quality. All 46 samples eligible for genomic profiling were successfully hybridised, and the results were reported on average within 4-5d. CONCLUSION Gene expression profiling on fresh frozen tissue is feasible in daily clinical practice.

Additional prognostic value of the 70-gene signature (MammaPrint(®)) among breast cancer patients with 4-9 positive lymph nodes

BACKGROUND The 70 gene-signature (MammaPrint(®)) is a prognostic profile of distant recurrence and survival of primary breast cancer (BC). BC patients with 4-9 positive nodes (LN 4-9) are considered clinically at high-risk. Herein we examined MammaPrint(®) added prognostic value in this group. PATIENTS AND METHODS MammaPrint(®) profiles were generated from frozen tumours of patients operated from primary BC. Samples were classified as genomic Low Risk (GLR) or genomic High Risk (GHR). RESULTS Among the 173 samples, 70 (40%) were classified as GLR and 103 (60%) as GHR. Tumours in the GHR group were significantly more often ductal carcinomas (93%), grade 3 (60%), oestrogen and progesterone-negative, Her2 positive (25%). In the GLR category, the 5-year overall survival was 97% vs. 76% for in the GHR group (p < 0.01); Distant Metastasis Free Survival (DMFS) at 5 years was 87% for GLR patients and 63% for GHR patients (p < 0.01). In the Luminal A subgroup, the genomic profile was the only independent risk factor for DM and BC specific death. CONCLUSION In the Luminal A subgroup, MammaPrint(®) is an independent prognostic marker in BC patients with LN 4-9 and may be integrated in a selection strategy of patients candidate for more aggressive therapeutic approaches.

Additional value of the 70-gene signature and levels of ER and PR for the prediction of outcome in tamoxifen-treated ER-positive breast cancer

BACKGROUND Breast cancer patients with node positive disease can have an excellent outcome with tamoxifen only. It is unclear whether analysing both the 70-gene signature and hormone receptors provides superior prediction of outcome in tamoxifen-treated patients than either alone. METHODS Three series were evaluated: 121 patients (81% node positive) received adjuvant tamoxifen, 151 patients did not receive tamoxifen (10% node positive) and 92 patients received tamoxifen for metastatic disease. The 70-gene signature was analysed using MammaPrint. Oestrogen receptor (ER) and progesterone receptor (PR) immunohistochemistry was evaluated following St. Gallen Consensus (Highly Endocrine Responsive: ER and PR ≥ 50%, Incompletely Endocrine Responsive: ER and/or PR low or either one absent). RESULTS In patients treated with adjuvant tamoxifen, both the 70-gene signature (adjusted for Endocrine Response Categories HR 2.17, 95%CI 1.01-4.66) as well as the Endocrine Response Categories (adjusted for 70-gene signature HR 6.35, 95%CI 1.90-21.3) were associated with breast-cancer-specific-survival (BCSS). Also in patients treated with tamoxifen for metastatic disease, combined analysis of the 70-gene signature and ER/PR revealed additional value (multivariate Cox regression, p = 0.013). In patients who did not receive tamoxifen, only the 70-gene signature was associated with outcome. CONCLUSION In the series analysed, the 70-gene signature was mainly a prognostic factor, while ER and PR levels were mainly associated with outcome after tamoxifen. Combination of these three factors may improve outcome prediction in tamoxifen-treated patients.

MammaPrint 70-gene profile quantifies the likelihood of recurrence for early breast cancer

BACKGROUND Over the past few years, a variety of multigene expression profiles have been developed to improve prognostication for early stage breast cancer and reduce overtreatment with chemotherapy. MammaPrint is the only test cleared by the US Food and Drug Administration for the prognostication of early breast cancer. The MammaPrint assay examines the expression of 70 genes in the primary tumor to stratify patients diagnosed with early stage breast cancer into good and poor prognosis groups. OBJECTIVE This evaluation reviews the development of the 70-gene profile, including validation studies involving patients with node-negative and 1 - 3 node-positive disease, the conversion of the 70-gene profile to a high-throughput diagnostic test, and the continuing prospective MINDACT clinical trial. CONCLUSION The MammaPrint assay should help to determine which women with early breast cancer could be spared adjuvant chemotherapy.