Eleni Andreopoulou

A Genomic Predictor of Response and Survival Following Taxane-Anthracycline Chemotherapy for Invasive Breast Cancer

CONTEXT Prediction of high probability of survival from standard cancer treatments is fundamental for individualized cancer treatment strategies. OBJECTIVE To develop a predictor of response and survival from chemotherapy for newly diagnosed invasive breast cancer. DESIGN, SETTING, AND PATIENTS Prospective multicenter study conducted from June 2000 to March 2010 at the M. D. Anderson Cancer Center to develop and test genomic predictors for neoadjuvant chemotherapy. Patients were those with newly diagnosed ERBB2 (HER2 or HER2/neu)-negative breast cancer treated with chemotherapy containing sequential taxane and anthracycline-based regimens (then endocrine therapy if estrogen receptor [ER]-positive). Different predictive signatures for resistance and response to preoperative (neoadjuvant) chemotherapy (stratified according to ER status) were developed from gene expression microarrays of newly diagnosed breast cancer (310 patients). Breast cancer treatment sensitivity was then predicted using the combination of signatures for (1) sensitivity to endocrine therapy, (2) chemoresistance, and (3) chemosensitivity, with independent validation (198 patients) and comparison with other reported genomic predictors of chemotherapy response. MAIN OUTCOME MEASURES Distant relapse-free survival (DRFS) if predicted treatment sensitive and absolute risk reduction ([ARR], difference in DRFS between 2 predicted groups) at median follow-up (3 years). RESULTS Patients in the independent validation cohort (99% clinical stage II-III) who were predicted to be treatment sensitive (28%) had 56% (95% CI, 31%-78%) probability of excellent pathologic response and DRFS of 92% (95% CI, 85%-100%), with an ARR of 18% (95% CI, 6%-28%). Survival was predicted in ER-positive (30% predicted sensitive; DRFS, 97% [95% CI, 91%-100%]; ARR, 11% [95% CI, 0.1%-21%]) and ER-negative (26% predicted sensitive; DRFS, 83% [95% CI, 68%-100%]; ARR, 26% [95% CI, 4%-48%]) subsets and was significant in multivariate analysis. Other genomic predictors showed paradoxically worse survival for patients predicted to be responsive to chemotherapy. CONCLUSION A genomic predictor combining ER status, predicted chemoresistance, predicted chemosensitivity, and predicted endocrine sensitivity identified patients with high probability of survival following taxane and anthracycline chemotherapy.

Comparison of assay methods for detection of circulating tumor cells in metastatic breast cancer: AdnaGen AdnaTest BreastCancer Select/Detect™ versus Veridex CellSearch™ system

The detection of CTCs prior to and during therapy is an independent and strong prognostic marker, and it is predictive of poor treatment outcome. A major challenge is that different technologies are available for isolation and characterization of CTCs in peripheral blood (PB). We compare the CellSearch system and AdnaTest BreastCancer Select/Detect, to evaluate the extent that these assays differ in their ability to detect CTCs in the PB of MBC patients. CTCs in 7.5 ml of PB were isolated and enumerated using the CellSearch, before new treatment. Two cutoff values of ≥2 and ≥5 CTCs/7.5 ml were used. AdnaTest requires 5 ml of PB to detect gene transcripts of tumor markers (GA733‐2, MUC‐1, and HER2) by RT‐PCR. AdnaTest was scored positive if ≥1 of the transcript PCR products for the 3 markers were detected at a concentration ≥0.15 ng/μl. A total of 55 MBC patients were enrolled. 26 (47%) patients were positive for CTCs by the CellSearch (≥2 cutoff), while 20 (36%) were positive (≥5 cutoff). AdnaTest was positive in 29 (53%) with the individual markers being positive in 18% (GA733‐2), 44% (MUC‐1), and 35% (HER2). Overall positive agreement was 73% for CTC≥2 and 69% for CTC≥5. These preliminary data suggest that the AdnaTest has equivalent sensitivity to that of the CellSearch system in detecting 2 or more CTCs. While there is concordance between these 2 methods, the AdnaTest complements the CellSearch system by improving the overall CTC detection rate and permitting the assessment of genomic markers in CTCs.

Circulating Tumor Cells and [18F]Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for Outcome Prediction in Metastatic Breast Cancer

PURPOSE Circulating tumor cells (CTCs) and [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) are two new promising tools for therapeutic monitoring. In this study, we compared the prognostic value of CTC and FDG-PET/CT monitoring during systemic therapy for metastatic breast cancer (MBC). PATIENTS AND METHODS A retrospective analyses of 115 MBC patients who started a new line of therapy and who had CTC counts and FDG-PET/CT scans performed at baseline and at 9 to 12 weeks during therapy (midtherapy) was performed. Patients were categorized according to midtherapy CTC counts as favorable (ie, < five CTCs/7.5 mL blood) or unfavorable (> or = five CTCs/7.5 mL blood) outcomes. CTC counts and FDG-PET/CT response at midtherapy were compared, and univariate and multivariate analyses were performed to identify factors associated with survival. RESULTS In 102 evaluable patients, the median overall survival time was 14 months (range, 1 to > 41 months). Midtherapy CTC levels correlated with FDG-PET/CT response in 68 (67%) of 102 evaluable patients. In univariate analysis, midtherapy CTC counts and FDG-PET/CT response predicted overall survival (P < .001 and P = .001, respectively). FDG-PET/CT predicted overall survival (P = .0086) in 31 (91%) of 34 discordant patients who had fewer than five CTCs at midtherapy. Only midtherapy CTC levels remained significant in a multivariate analysis (P = .004). CONCLUSION Detection of five or more CTCs during therapeutic monitoring can accurately predict prognosis in MBC beyond metabolic response. FDG-PET/CT deserves a role in patients who have fewer than five CTCs at midtherapy. Prospective trials should evaluate the most sensitive and cost-effective modality for therapeutic monitoring in MBC.

Detection of minimal residual disease in blood and bone marrow in early stage breast cancer.

The significance of circulating tumor cells (CTCs) in blood and of disseminated tumor cells (DTCs) in bone marrow (BM) in patients with early stage breast cancer is unclear. In this study, the authors investigated the occurrence of CTCs and DTCs in women with early stage breast cancer and evaluated the correlation of their presence with other prognostic markers.

Assessment of an RNA interference screen-derived mitotic and ceramide pathway metagene as a predictor of response to neoadjuvant paclitaxel for primary triple-negative breast cancer: a retrospective analysis of five clinical trials.

BACKGROUND Addition of taxanes to preoperative chemotherapy in breast cancer increases the proportion of patients who have a pathological complete response (pCR). However, a substantial proportion of patients do not respond, and the prognosis is particularly poor for patients with oestrogen-receptor (ER)/progesterone-receptor (PR)/human epidermal growth factor receptor 2 (HER2; ERBB2)-negative (triple-negative) disease who do not achieve a pCR. Reliable identification of such patients is the first step in determining who might benefit from alternative treatment regimens in clinical trials. We previously identified genes involved in mitosis or ceramide metabolism that influenced sensitivity to paclitaxel, with an RNA interference (RNAi) screen in three cancer cell lines, including a triple-negative breast-cancer cell line. Here, we assess these genes as a predictor of pCR to paclitaxel combination chemotherapy in triple-negative breast cancer. METHODS We derived a paclitaxel response metagene based on mitotic and ceramide genes identified by functional genomics studies. We used area under the curve (AUC) analysis and multivariate logistic regression to retrospectively assess the metagene in six cohorts of patients with triple-negative breast cancer treated with neoadjuvant chemotherapy; two cohorts treated with paclitaxel (n=27, 30) and four treated without paclitaxel (n=88, 28, 48, 39). FINDINGS The metagene was associated with pCR in paclitaxel-treated cohorts (AUC 0.79 [95% CI 0.53-0.93], 0.72 [0.48-0.90]) but not in non-paclitaxel treated cohorts (0.53 [0.31-0.77], 0.59 [0.22-0.82], 0.53 [0.36-0.71], 0.64 [0.43-0.81]). In multivariate logistic regression, the metagene was associated with pCR (OR 19.92, 2.62-151.57; p=0.0039) with paclitaxel-containing chemotherapy. INTERPRETATION The paclitaxel response metagene shows promise as a paclitaxel-specific predictor of pCR in patients with triple-negative breast cancer. The metagene is suitable for development into a reverse transcription-PCR assay, for which clinically relevant thresholds could be established in randomised clinical trials. These results highlight the potential for functional genomics to accelerate development of drug-specific predictive biomarkers without the need for training clinical trial cohorts. FUNDING UK Medical Research Council; Cancer Research UK; the National Institute for Health Research (UK); the Danish Council for Independent Research-Medical Sciences (FSS); Breast Cancer Research Foundation (New York); Fondation Luxembourgeoise contre le Cancer; the Fonds National de la Recherche Scientifique; Brussels Region (IRSIB-IP, Life Sciences 2007) and Walloon Region (Biowin-Keymarker); Sally Pearson Breast Cancer Fund; and the European Commission.

Characterization of metastatic breast cancer patients with nondetectable circulating tumor cells

Circulating tumor cells (CTC) are an independent prognostic factor in metastatic breast cancer patients (MBC). However, CTC are undetectable in one third of patients. The aim of this study was to assess the prognostic factors in MBC patients without detectable CTC. This retrospective study included 292 MBC patients evaluated between January 2004 and December 2007. CTC were enumerated before patients started a new line of treatment using the CellSearch™. Overall survival (OS) was calculated from the date of CTC measurement and estimated by the Kaplan‐Meier product limit method. CTC were not detected in 35.96% patients, whereas 40.75% patients had CTC ≥ 5. Undetectable CTC status was positively correlated with presence of brain metastasis (OR: 6.17, 95%CI = 2.14–17.79; p = 0.001), and inversely correlated with bone metastasis (OR: 0.47; 95%CI = 0.27–0.80; p = 0.01). In multivariate analysis, hormone receptors, number of metastatic sites and lines of therapy were independent prognostic factors for OS in patients without detectable CTC. Patients without detectable CTC before starting of a new line of therapy comprise a heterogeneous group with substantially different prognosis. We showed that some important metastatic disease characteristics are predictive of undetectable CTC status in MBC.

Circulating tumor cells in immunohistochemical subtypes of metastatic breast cancer: lack of prediction in HER2-positive disease treated with targeted therapy

BACKGROUND Circulating tumor cells (CTCs) are associated with inferior prognosis in metastatic breast cancer (MBC). We hypothesized that the relationship between CTCs and disease subtype would provide a better understanding of the clinical and biologic behavior of MBC. PATIENTS AND METHODS We retrospectively analyzed 517 MBC patients treated at a single institution. Subtypes of primary tumors were analyzed by immunohistochemical (IHC) or fluorescent in situ hybridization analyses and CTCs were enumerated by CellSearch® at starting a new therapy. Overall survival (OS) and progression-free survival durations for each IHC subtype were determined. RESULTS At a median follow-up of 24.6 months, 276 of 517 (53%) patients had died. The median OS for patients with <5 and ≥5 CTCs were 32.4 and 18.3 months, respectively (P < 0.001). Except in HER2+ patients, the prognostic value of CTCs was independent of disease subtype and disease site. CONCLUSIONS In this large retrospective study, CTCs were strongly predictive of survival in all MBC subtypes except HER2+ patients who had been treated with targeted therapy. Our results clearly demonstrate the value of enumerating CTCs in MBC and strongly suggest an interesting biological implication in the HER2+ subset of patients that need to be further explored.BACKGROUND Circulating tumor cells (CTCs) are associated with inferior prognosis in metastatic breast cancer (MBC). We hypothesized that the relationship between CTCs and disease subtype would provide a better understanding of the clinical and biologic behavior of MBC. PATIENTS AND METHODS We retrospectively analyzed 517 MBC patients treated at a single institution. Subtypes of primary tumors were analyzed by immunohistochemical (IHC) or fluorescent in situ hybridization analyses and CTCs were enumerated by CellSearch(®) at starting a new therapy. Overall survival (OS) and progression-free survival durations for each IHC subtype were determined. RESULTS At a median follow-up of 24.6 months, 276 of 517 (53%) patients had died. The median OS for patients with <5 and ≥ 5 CTCs were 32.4 and 18.3 months, respectively (P < 0.001). Except in HER2+ patients, the prognostic value of CTCs was independent of disease subtype and disease site. CONCLUSIONS In this large retrospective study, CTCs were strongly predictive of survival in all MBC subtypes except HER2+ patients who had been treated with targeted therapy. Our results clearly demonstrate the value of enumerating CTCs in MBC and strongly suggest an interesting biological implication in the HER2+ subset of patients that need to be further explored.

Prognostic Factors in Metastatic Breast Cancer: Successes and Challenges Toward Individualized Therapy

A pivotal article by Hortobagyi et al in the 1983 Volume 1 issue of Journal of Clinical Oncology addressed the impact of predictive and prognostic models in the setting of metastatic breast cancer. At that time, clinical variables were used in a forward stepwise logistic regression procedure to determine the patient characteristics important in predicting response to doxorubicin-containing chemotherapeutic regimens. Three models for assessing prognosis were generated by this study, which pioneered the use of mathematical algorithmic probability equations and biologic stratification as predictors for individual, rather than random, outcomes. Within the past two decades, the management of metastatic breast cancer has evolved, with the introduction of new chemotherapeutic agents (taxanes, vinorelbine, gemcitabine, and capecitabine), newer hormonal agents, including third-generation aromatase inhibitors, and biologic therapies, such as trastuzumab, bevacizumab, and lapatinib. However, metastatic breast cancer remains incurable, though therapeutic innovation has resulted in modest improvements in survival rates. The original article proposed a model of prognostication with a purely demographic and anatomic base. Since then, thinking has evolved to a biologic and genetic platform. The introduction of novel technology has enabled scientists to further classify breast tumors using methods that can measure differences in thousands of biologic pathways simultaneously. The purpose of this editorial is to highlight the article’s original perspective in light of the rapidly changing field of predictors of response and individualized therapy for the treatment of patients with breast cancer. The original models proposed are still useful in the estimation of risk in patients with breast cancer. Even today, anatomic staging continues to play a major role in guiding treatment decisions. The extent of the disease, disease-free intervals, prior adjuvant therapy, and performance status remain of prognostic value. Although the level of risk may be useful in deciding between certain types of regimens (chemotherapy v hormonal therapy) as an initial treatment option, it does not offer guidance as to actual drug selection for individual patients. It has become clear that the unpredictable clinical behavior of metastatic breast cancer reflects the biologic heterogeneity of the disease. This heterogeneity introduces subgroups that benefit from therapeutic innovations and likely account for the modest improvements in survival. Current technology provides a powerful method to help identify and validate new drug targets, as well as potential diagnostic and prognostic markers for use as predictors of response to new molecular therapeutics. In light of this, the focus has moved increasingly away from dose escalation and intensification of chemotherapy in otherwise unselected patients to the premise of targeting specific biologic pathways in selected patients using pharmacologic or immunologic methods. Although the prototype target in breast cancer has been known for approximately 40 years, we only came to accept, after the 1995 Oxford overview, that essentially all the benefit derived from tamoxifen is limited to patients with estrogen receptor (ER) –positive breast cancer, regardless of stage and age. However, not every patient with ER-positive breast cancer benefits from tamoxifen. For this reason, several endocrine approaches have been developed that interrupt estrogen stimulation, either by directly modulating the ER-signaling pathway or by lowering serum or tumor concentrations of estrogen. Beyond the classic pathway, new evidence suggests that cross-talk exists between the ER and growth factor receptor pathways, contributing to de novo and acquired resistance to endocrine therapy. Inappropriate activation of growth factor signaling can readily promote endocrine therapy failure in breast cancer cells, by either overriding the growth-inhibitory properties of antiestrogenic drugs or by the establishment of a new self-propagating autocrine loop that efficiently drives resistant cell growth. Modern therapies also target deregulated critical biochemical pathways present in cancer cells that result in changes in normal cellular processes such as apoptosis, proliferation, angiogenesis, DNA repair, cell cycle progression, invasion, and metastases. Like ER, some of these molecular defects have prognostic or predictive value, whereas others are implicated in resistance to chemotherapy or hormone therapy. Drugs that target these pathways have been demonstrated to improve response and/or survival in patients with metastatic breast cancer. The adverse prognosis of the human epidermal growth factor receptor 2 (HER2) –positive breast cancer has been recognized since the seminal publication by Slamon et al 20 years ago. Ten years ago, randomized trials of anti-HER2 therapy added to first-line chemotherapy in patients with HER2-overexpressing metastatic disease showed increased clinical benefit and survival. For certain agents, such as lapatinib and trastuzumab, a preclinical knowledge of the drugs’ target led to appropriate patient selection, JOURNAL OF CLINICAL ONCOLOGY C E L E B R A T I N G 2 5 Y E A R S O F J C O VOLUME 26 NUMBER 22 AUGUST 1 2008

Circulating tumor cells as prognostic marker in metastatic breast cancer

Testing for circulating tumor cells has emerged as a new and promising tool for stratifying and monitoring patients with metastatic disease. Appropriate risk and biologic stratification in breast cancer is important for the development of more effectively tailored targeted therapies. To optimize patient care, it is important for the clinicians to rely on validated and robust tools able to provide accurate predictive and prognostic information for each patient at any time during treatment. The recent demonstration that the presence of circulating tumor cells predicts the prognosis at any time during the treatment of patients with metastatic breast cancer raises the possibility that this approach will allow for a true ‘biologic staging’ of the disease. Important questions regarding the biological characteristics of cells and the reasons for the reduced capacity of systemic treatments to arrest or eradicate the cancer were raised. A further study suggests that comprehensive analysis of circulating tumor cells is likely to provide new insights into the biology of breast cancer and contribute to defining novel treatments and better prediction of clinical benefit. Efforts are being made to genotype and phenotype micrometastatic cells. Considerable progress has been already accomplished which should lead to further noninvasive, real-time monitoring of these rare events in the adjuvant and metastatic settings.

Coping with uncertainty: T1a,bN0M0 HER2-positive breast cancer, do we have a treatment threshold?

BACKGROUND Recent retrospective studies have suggested that patients with T1a,bN0M0 human epidermal growth factor receptor 2 (HER2)-positive breast cancer are at a higher risk for recurrence and might benefit from adjuvant trastuzumab. The absolute benefits associated with treating this subgroup are uncertain. DESIGN We reviewed recent studies examining the prognostic value of HER2 in patients with node-negative T1a,b HER2-positive breast cancer. We calculated the number needed to treat (NNT) using baseline risk estimates for untreated T1a,bN0M0 breast cancer and the number needed to harm (NNH) using the incidence of cardiac events in each of the adjuvant trastuzumab clinical trials. RESULTS Several studies were identified, each with limitations inherent to retrospective database analyses: small cohort sizes, lack of systematic HER2 testing in older specimens, variations in the use of adjuvant therapy and definitions of study end points, and lack of information relating to comorbidities. The 5-year disease-free survival in the pre-trastuzumab era ranged from 77% to 95%. Comparisons between small HER2 -positive and small HER2 -negative cancers showed numerically worse outcome for the HER2-positive cohort in some but not all studies. In many instances, the NNH was larger (26-250) than the NNT (13-35); however, in a subset of patients, the NNH was lower (6) than the NNT (13-35). CONCLUSIONS Better prediction tools to estimate more precisely the risk for death due to comorbid illness versus breast cancer are needed. In some patients, the risks of therapy could outweigh the benefits. Treatment selection for T1a,bN0 HER2-positive cancers remains in the transition area between evidence- and subjective judgment-based medicine.