Circulating tumor cells detected in follow-up predict survival outcomes in tri-modality management of advanced non-metastatic esophageal cancer: a secondary analysis of the QUINTETT randomized trial

Background

Our aim was to establish if presence of circulating tumor cells (CTCs) predicted worse outcome in patients with non-metastatic esophageal cancer undergoing tri-modality therapy.

Methods

We prospectively collected CTC data from patients with operable non-metastatic esophageal cancer from April 2009 to November 2016 enrolled in our QUINTETT esophageal cancer randomized trial (NCT00907543). Patients were randomized to receive either neoadjuvant cisplatin and 5-fluorouracil (5-FU) plus radiotherapy followed by surgical resection (Neoadjuvant) or adjuvant cisplatin, 5-FU, and epirubicin chemotherapy with concurrent extended volume radiotherapy following surgical resection (Adjuvant). CTCs were identified with the CellSearch® system before the initiation of any treatment (surgery or chemoradiotherapy) as well as at 6-, 12-, and 24-months post-treatment. The threshold for CTC positivity was one and the findings were correlated with patient prognosis.

Results

CTC data were available for 74 of 96 patients and identified in 27 patients (36.5%) at a median follow-up of 13.1months (interquartile range:6.8-24.1 months). Detection of CTCs at any follow-up visit was significantly predictive of worse disease-free survival (DFS;hazard ratio [HR]: 2.44; 95% confidence interval [CI]: 1.41-4.24; p=0.002), regional control (HR: 6.18; 95% CI: 1.18-32.35; p=0.031), distant control (HR: 2.93; 95% CI: 1.52-5.65;p=0.001) and overall survival (OS;HR: 2.02; 95% CI: 1.16-3.51; p=0.013). After adjusting for receiving neoadjuvant vs. adjuvant chemoradiotherapy, the presence of CTCs at any follow-up visit remained significantly predictive of worse OS ([HR]:2.02;95% [Cl]:1.16-3.51; p=0.013) and DFS (HR: 2.49;95% Cl: 1.43-4.33; p=0.001). Similarly, any observed increase in CTCs was significantly predictive of worse OS (HR: 3.14; 95% CI: 1.56-6.34; p=0.001) and DFS (HR: 3.34; 95% CI: 1.67-6.69; p<0.001).

Conclusion

The presence of CTCs in patients during follow-up after tri-modality therapy was associated with significantly poorer DFS and OS regardless of timing of chemoradiotherapy.

Characterization of circulating tumor cells in early breast cancer patients receiving neoadjuvant chemotherapy

Background and Aims:

The aim of this study was to characterize circulating tumor cells (CTCs) during neoadjuvant chemotherapy (NACT) in early and locally advanced breast cancer (LABC) patients. Using ultrasound, tumor volume measurement was compared with the presence and the molecular nature of CTCs over multiple time intervals corresponding to treatment periods.

Methods:

A total of 20 patients diagnosed with breast cancer (BC) of different histotypes were monitored during the NACT period and in the follow-up period (~5 years). Peripheral blood for CTCs (n = 115) was taken prior to NACT, after two to three chemotherapy cycles, after the completion of NACT (before surgery) and at some time points during adjuvant therapy. CTCs were enriched using a size-based filtration method (MetaCell®) capturing viable cells, which enabled vital fluorescence microscopy. A set of tumor-associated (TA) genes and chemoresistance-associated (CA) genes was analyzed by qPCR in the enriched CTC fractions.

Results:

The analysis of tumor volume reduction after administration of anthracyclines (AC) and taxanes (TAX) during NACT showed that AC therapy was responsive in 60% (12/20) of tumors, whereas TAX therapy was responsive in 30% (6/20; n.s.). After NACT, CTCs were still present in 70.5% (12/17) of patients (responders versus non-responders, 61.5% versus 100%; not significant).

In triple-negative BC (TNBC) patients (n = 8), tumor volume reduction was observed in 75% cases. CTCs were significantly reduced in 42.9% of all HER2-negative BC patients. In HER2+ tumors, CTC reduction was reported in 16.6% only. Relapses were also more prevalent in the HER2-positive patient group (28.5 versus 66.6%).

During NACT, the presence of CTCs (three tests for each patient) identified patients with relapses and indicated significantly shorter progression-free survival (PFS) rates (p = 0.03). Differentiation between progressive disease and non-progressive disease was obtained when the occurrence of excessive expression for CA genes in CTCs was compared (p = 0.024). Absence of tumor volume reduction was also significantly indicative for progressive disease (p = 0.0224).

Disseminated CTCs in HER2-negative tumors expressed HER2 in 29% of samples collected during the overall follow-up period (16/55), and in 32% of samples during the follow-up of NACT (10/31). The change accounted for 78.5% of HER2-negative patients (11/14) in total, and 63.6% of the conversion cases occurred during NACT (7/11). For the remaining four patients (36.3%), conversion to HER2+ CTCs occurred later during adjuvant therapy. We believe there is the possibility of preventing further progression by identifying less responsive tumors during NACT using CTC monitoring, which could also be used effectively during adjuvant therapy.

Breast Cancer Cell Re-Dissemination from Lung Metastases-A Mechanism for Enhancing Metastatic Burden

Although metastatic disease is the primary cause of mortality in cancer patients, the mechanisms leading to overwhelming metastatic burden are still incompletely understood. Metastases are the endpoint of a series of multi-step events involving cancer cell intravasation, dissemination to distant organs, and outgrowth to metastatic colonies. Here we show, for the first-time, that breast cancer cells do not solely disseminate to distant organs from primary tumors and metastatic nodules in the lymph nodes, but also do so from lung metastases. Thus, our findings indicate that metastatic dissemination could continue even after the removal of the primary tumor. Provided that the re-disseminated cancer cells initiate growth upon arrival to distant sites, cancer cell re-dissemination from metastatic foci could be one of the crucial mechanisms leading to overt metastases and patient demise. Therefore, the development of new therapeutic strategies to block cancer cell re-dissemination would be crucial to improving survival of patients with metastatic disease.

Highly Correlated Recurrence Prognosis in Patients with Metastatic Colorectal Cancer by Synergistic Consideration of Circulating Tumor Cells/Microemboli and Tumor Markers CEA/CA19-9

Circulation tumor cells (CTCs) play an important role in metastasis and highly correlate with cancer progression; thus, CTCs could be considered as a powerful diagnosis tool. Our previous studies showed that the number of CTCs could be utilized for recurrence prediction in colorectal cancer (CRC); however, the odds ratio was still lower than five. To improve prognosis in CRC patients, we analyzed CTC clusters/microemboli, CTC numbers, and carcinoembryonic antigen (CEA)/carbohydrate antigen 19-9 (CA19-9) levels using a self-assembled cell array (SACA) chip system for recurrence prediction. In CRC patients, the presence of CTC clusters/microemboli may have higher correlation in metastasis when compared to the high number of CTCs. Additionally, when both the number of CTCs and serum CEA levels are high, very high odds ratios of 24.4 and 17.1 are observed in patients at all stages and stage III of CRC, respectively. The high number of CTCs and CTC clusters/microemboli simultaneously suggests the high chance of relapse (odds ratio 8.4). Overall, the characteristic of CTC clusters/microemboli, CEA level, and CTC number have a clinical potential to enhance CRC prognosis.

Microfluidics and Nanomaterial-based Technologies for Circulating Tumor Cell Isolation and Detection

Cancer has been one of the leading causes of death globally, with metastases and recurrences contributing to this result. The detection of circulating tumor cells (CTCs), which have been implicated as a major population of cells that is responsible for seeding and migration of tumor sites, could contribute to early detection of metastasis and recurrences, consequently increasing the chances of cure. This review article focuses on the current progress in microfluidics technology in CTCs diagnostics, extending to the use of nanomaterials and surface modification techniques for diagnostic applications, with an emphasis on the importance of integrating microchannels, nanomaterials, and surface modification techniques in the isolating and detecting of CTCs.

The Significance of Circulating Tumour Cells in the Clinic

BACKGROUND

Despite the hype about circulating tumour cells (CTCs) in the early 2000s and their potential in the diagnosis of metastasis, in recent years, the hope for personalised cancer management relies more on circulating tumour (ct)DNA that has entered the clinic in a much more efficient way. So far, approved methods for CTCs in the clinic only provide the counting of CTCs, which enables monitoring of the progression of metastatic breast, prostate, and colorectal cancer patients with therapy. Approved methods for ctDNA facilitate the analysis of specific mutations in lung cancer, thereby providing indications for potentially successful treatments. This situation inclined the balance towards molecular analysis in liquid biopsy, leveraged by new technologies and companies providing broader mutation and gene expression analysis towards the early diagnosis of cancer.

STUDY DESIGN

We conducted a search for the studies published to date that provide details about the significance of CTCs in the clinic.

RESULTS

Many studies and clinical trials have demonstrated the potential of CTCs in patient screening, early diagnosis, therapy resistance, and patient prognosis.

CONCLUSIONS

Large multi-centre studies are still needed to formally validate the clinical relevance of CTCs. Meticulous design of the clinical trials is a crucial point to achieve this long-sought objective.

Design of a Novel MEMS Microgripper with Rotatory Electrostatic Comb-Drive Actuators for Biomedical Applications

Primary tumors of patients can release circulating tumor cells (CTCs) to flow inside of their blood. The CTCs have different mechanical properties in comparison with red and white blood cells, and their detection may be employed to study the efficiency of medical treatments against cancer. We present the design of a novel MEMS microgripper with rotatory electrostatic comb-drive actuators for mechanical properties characterization of cells. The microgripper has a compact structural configuration of four polysilicon layers and a simple performance that control the opening and closing displacements of the microgripper tips. The microgripper has a mobile arm, a fixed arm, two different actuators and two serpentine springs, which are designed based on the SUMMiT V surface micromachining process from Sandia National Laboratories. The proposed microgripper operates at its first rotational resonant frequency and its mobile arm has a controlled displacement of 40 µm at both opening and closing directions using dc and ac bias voltages. Analytical models are developed to predict the stiffness, damping forces and first torsional resonant frequency of the microgripper. In addition, finite element method (FEM) models are obtained to estimate the mechanical behavior of the microgripper. The results of the analytical models agree very well respect to FEM simulations. The microgripper has a first rotational resonant frequency of 463.8 Hz without gripped cell and it can operate up to with maximum dc and ac voltages of 23.4 V and 129.2 V, respectively. Based on the results of the analytical and FEM models about the performance of the proposed microgripper, it could be used as a dispositive for mechanical properties characterization of circulating tumor cells (CTCs).

Integration of biomimicry and nanotechnology for significantly improved detection of circulating tumor cells (CTCs)

Circulating tumor cells (CTCs) have received a great deal of scientific and clinical attention as a biomarker for diagnosis and prognosis of many types of cancer. Given their potential significance in clinics, a variety of detection methods, utilizing the recent advances in nanotechnology and microfluidics, have been introduced in an effort of achieving clinically significant detection of CTCs. However, effective detection and isolation of CTCs still remain a tremendous challenge due to their extreme rarity and phenotypic heterogeneity. Among many approaches that are currently under development, this review paper focuses on a unique, promising approach that takes advantages of naturally occurring processes achievable through application of nanotechnology to realize significant improvement in sensitivity and specificity of CTC capture. We provide an overview of successful outcome of this biomimetic CTC capture system in detection of tumor cells from in vitro, in vivo, and clinical pilot studies. We also emphasize the clinical impact of CTCs as biomarkers in cancer diagnosis and predictive prognosis, which provides a cost-effective, minimally invasive method that potentially replaces or supplements existing methods such as imaging technologies and solid tissue biopsy. In addition, their potential prognostic values as treatment guidelines and that ultimately help to realize personalized therapy are discussed.

Phase II Randomized Study of Ixabepilone Versus Observation in Patients With Significant Residual Disease After Neoadjuvant Systemic Therapy for HER2-Negative Breast Cancer

BACKGROUND

Residual disease (RD) after neoadjuvant chemotherapy carries an increased risk for recurrence. Ixabepilone has activity in anthracycline/taxanes-resistant breast cancer. We explored adjuvant ixabepilone in patients with significant RD HER2-negative breast cancer.

METHODS

A phase II study in patients with residual cancer burden II or III randomized to ixabepilone versus observation was conducted. Circulating tumor cells (CTCs) were measured at baseline and at 9 and 18 weeks. Survival probabilities were estimated by Kaplan-Meier product limit. Toxicities were reported as proportions in the ixabepilone arm.

RESULTS

Accrual was stopped because of ixabepilone toxicity. Sixty-seven patients were registered; 43 were randomized, 19 received ixabepilone, and 24 went to observation. One patient (9.1%) in the observation arm versus 2 patients (18.2%) in the ixabepilone arm had CTCs at 18 weeks (P = 1.0). Three-year recurrence-free survival and overall survival were 94% and 82%, and 100% and 79% in the observation and ixabepilone arms (P = .35 and .18), respectively. Most common adverse events (AEs) included fatigue, pain, neuropathy, constipation, nausea, rash, anorexia, and diarrhea. Serious AEs included pain (63.2%), fatigue (31.6%), and neuropathy (31.6%).

CONCLUSIONS

Adjuvant ixabepilone in patients with significant RD after neoadjuvant chemotherapy was difficult to administer because of AEs and did not change the presence of CTC or affect survival outcomes. NCT00877500.

The HER2 peptide nelipepimut-S (E75) vaccine (NeuVax™) in breast cancer patients at risk for recurrence: correlation of immunologic data with clinical response

Nelipepimut-S (formerly known as E75) is an immunogenic peptide from the HER2 protein that is highly expressed in breast cancer. The NeuVax™ (Galena, OR, USA) vaccine, nelipepimut-S plus granulocyte-macrophage colony-stimulating factor, is designed for the prevention of clinical recurrences in high risk, disease-free breast cancer patients. Although cancer vaccines such as NeuVax represent promising approaches to cancer immunotherapy, much remains to be elucidated regarding their mechanisms of action: particularly given that multiple cancer vaccine trials have failed to demonstrate a correlation between immunologic data and clinical outcome. Here, we briefly discuss our clinical trial experience with NeuVax focusing on immunologic response data and its implication on how the immune system may be affected by this peptide vaccine. Most importantly, we demonstrate the potential capability of certain immunologic assays to predict clinical benefit in our trials.

Meta-analysis shows that circulating tumor cells including circulating microRNAs are useful to predict the survival of patients with gastric cancer

Background

Circulating tumor cells (CTCs) are metastatic cells disseminated into the bloodstreams. They have been proposed to monitor disease progression for decades. However, the prognostic value of CTCs in gastric cancer (GC) remains controversial. We performed a meta-analysis to investigate the topic.

Methods

A systematic search was made for relevant studies in academic data bases, involving the Medline, Embase, and Science Citation Index. Data on prognosis of GC patients, such as recurrence-free survival (RFS) and overall survival (OS), were extracted when possible. The meta-analysis was performed with the random effects model and the pooled hazard ratios (HRs) and their associated 95% confident intervals (95%CIs) were computed as effect measures.

Results

Twenty six studies (including 40 subgroups) with peripheral blood samples of 1950 cases from 10 countries were included in the final analysis. The pooled results showed that GC patients with detectable CTCs (including circulating miRNAs) had a tendency to experience shortened RFS (HR = 2.91, 95% CI [1.84-4.61], I² = 52.18%, n = 10). As for patient deaths, we found a similar association of CTC (including circulating miRNAs) presence with worse OS (HR = 1.78, 95% CI [1.49-2.12], I² = 30.71%, n = 30). Additionally, subgroup analyses indicated strong prognostic powers of CTCs, irrespective of geographical, methodological, detection time and sample size differences of the studies.

Conclusions

Our meta-analysis shows that CTCs (including circulating miRNAs) can predict the survival of GC patients. Large prospective studies are warranted to determine the best sampling time points, detection methods in homogeneous patients with GC in the future.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-773) contains supplementary material, which is available to authorized users.

Combined analysis of copy number alterations by single-nucleotide polymorphism array and MYC status in non-metastatic breast cancer patients: comparison according to the circulating tumor cell status

Recent technological advances have made it possible to detect circulating tumor cells (CTCs) as a prognostic marker in operable breast cancer patients. Whether the presence of CTCs in cancer patients correlates with molecular alterations in the primary tumor has not been widely explored. We identified 14 primary breast cancer specimens with known CTC status, in order to evaluate the presence of differential genetic aberrations by using SNP array assay. There was a global increase of altered genome, CNA, and copy-neutral loss of heterozygosity (cn-LOH) observed in the CTC-positive (CTC(+)) versus CTC-negative (CTC(-)) cases. As the preliminary results showed a higher proportion of copy number alteration (CNA) at 8q24 (MYC loci) and the available evidence supporting the role of MYC in the processes cancer metastases is conflicting, MYC status was determined in tissue microarray sections in a larger series of patients (n = 49) with known CTC status using FISH. MYC was altered in 62% (16/26) CTC(+) patients and in 43% (6/14) CTC(-) patients (p = 0.25). Based on the observation in our study, future studies involving a larger number of patients should be performed in order to definitively define if this correlation exists.

Analysis of circulating tumor cells in patients with triple negative breast cancer during preoperative chemotherapy

The presence of circulating tumor cells in the blood of patients with triple negative breast cancer (early and locally advanced cancer) before and after preoperative chemotherapy was assessed using expression markers. Before therapy, circulating tumor cells were detected in 5 of 13 (38%) patients with early cancer and in 7 of 17 (41.2%) patients with locally advanced cancer. After therapy, the circulating immune cells were detected in one patient with locally advanced cancer, who had no circulating cells before therapy. The tumor was resistant to chemotherapy and the disease progressed. The detected circulating tumor cells were HER-2-positive, while the primary tumor was HER-2-negative. It was concluded that the circulating immune cells can be a potential marker of the efficiency of therapy and predictors of the disease course, while their phenotype can differ from the phenotype of the primary tumor.

Mesenchymal phenotype of CTC-enriched blood fraction and lymph node metastasis formation potential

Introduction

Circulating tumor cells (CTCs) that present mesenchymal phenotypes can escape standard methods of isolation, thus limiting possibilities for their characterization. Whereas mesenchymal CTCs are considered to be more malignant than epithelial CTCs, factors responsible for this aggressiveness have not been thoroughly defined. This study analyzed the molecular profile related to metastasis formation potential of CTC-enriched blood fractions obtained by marker unbiased isolation from breast cancer patients without (N−) and with lymph nodes metastases (N+).

Materials and Methods

Blood samples drawn from 117 patients with early-stage breast cancer were enriched for CTCs using density gradient centrifugation and negative selection with anti-CD45 covered magnetic particles. In the resulting CTC-enriched blood fractions, expression of CK19, MGB1, VIM, TWIST1, SNAIL, SLUG, HER2, CXCR4 and uPAR was analyzed with qPCR. Results were correlated with patients' clinicopathological data.

Results

CTCs (defined as expression of either CK19, MGB1 or HER2) were detected in 41% (20/49) of N− and 69% (34/49) of N+ patients (P = 0.004). CTC-enriched blood fractions of N+ patients were more frequently VIM (P = 0.02), SNAIL (P = 0.059) and uPAR-positive (P = 0.03). Positive VIM, CXCR4 and uPAR status correlated with >3 lymph nodes involved (P = 0.003, P = 0.01 and P = 0.045, respectively). In the multivariate logistic regression MGB1 and VIM-positivity were independently related to lymph node involvement with corresponding overall risk of 3.2 and 4.2. Moreover, mesenchymal CTC-enriched blood fractions (CK19−/VIM+ and MGB1+ or HER2+) had 4.88 and 7.85-times elevated expression of CXCR4 and uPAR, respectively, compared with epithelial CTC-enriched blood fractions (CK19+/VIM− and MGB1+ or HER2+).

Conclusions

Tumors of N+ patients have superior CTC-seeding and metastatic potential compared with N- patients. These differences can be attributed to VIM, uPAR and CXCR4 expression, which endow tumor cells with particularly malignant phenotypes.

Can biomarker assessment on circulating tumor cells help direct therapy in metastatic breast cancer?

Circulating tumor cell (CTC) count has prognostic significance in metastatic breast cancer, but the predictive utility of CTCs is uncertain. Molecular studies on CTCs have often been limited by a low number of CTCs isolated from a high background of leukocytes. Improved enrichment techniques are now allowing molecular characterisation of single CTCs, whereby molecular markers on single CTCs may provide a real-time assessment of tumor biomarker status from a blood test or “liquid biopsy”, potentially negating the need for a more invasive tissue biopsy. The predictive ability of CTC biomarker analysis has predominantly been assessed in relation to HER2, with variable and inconclusive results. Limited data exist for other biomarkers, such as the estrogen receptor. In addition to the need to define and validate the most accurate and reproducible method for CTC molecular analysis, the clinical relevance of biomarkers, including gain of HER2 on CTC after HER2 negative primary breast cancer, remains uncertain. This review summarises the currently available data relating to biomarker evaluation on CTCs and its role in directing management in metastatic breast cancer, discusses limitations, and outlines measures that may enable future development of this approach.

Circulating tumor cells detection has independent prognostic impact in high-risk non-muscle invasive bladder cancer

High-risk non-muscle invasive bladder cancer (NMIBC) progresses to metastatic disease in 10-15% of cases, suggesting that micrometastases may be present at first diagnosis. The prediction of risks of progression relies upon EORTC scoring systems, based on clinical and pathological parameters, which do not accurately identify which patients will progress. Aim of the study was to investigate whether the presence of CTC may improve prognostication in a large population of patients with Stage I bladder cancer who were all candidate to conservative surgery. A prospective single center trial was designed to correlate the presence of CTC to local recurrence and progression of disease in high-risk T1G3 bladder cancer. One hundred two patients were found eligible, all candidate to transurethral resection of the tumor followed by endovesical adjuvant immunotherapy with BCG. Median follow-up was 24.3 months (minimum-maximum: 4-36). The FDA-approved CellSearch System was used to enumerate CTC. Kaplan-Meier methods, log-rank test and multivariable Cox proportional hazard analysis was applied to establish the association of circulating tumor cells with time to first recurrence (TFR) and progression-free survival. CTC were detected in 20% of patients and predicted both decreased TFR (log-rank p < 0.001; multivariable adjusted hazard ratio [HR] 2.92 [95% confidence interval: 1.38-6.18], p = 0.005), and time to progression (log-rank p < 0.001; HR 7.17 [1.89-27.21], p = 0.004). The present findings provide evidence that CTC analyses can identify patients with Stage I bladder cancer who have already a systemic disease at diagnosis and might, therefore, potentially benefit from systemic treatment.

Heterogeneity of mesenchymal markers expression-molecular profiles of cancer cells disseminated by lymphatic and hematogenous routes in breast cancer

Breast cancers can metastasize via hematogenous and lymphatic routes, however in some patients only one type of metastases are detected, suggesting a certain proclivity in metastatic patterns. Since epithelial-mesenchymal transition (EMT) plays an important role in cancer dissemination it would be worthwhile to find if a specific profile of EMT gene expression exists that is related to either lymphatic or hematogenous dissemination. Our study aimed at evaluating gene expression profile of EMT-related markers in primary tumors (PT) and correlated them with the pattern of metastatic spread. From 99 early breast cancer patients peripheral blood samples (N = 99), matched PT (N = 47) and lymph node metastases (LNM; N = 22) were collected. Expression of TWIST1, SNAI1, SNAI2 and VIM was analyzed in those samples. Additionally expression of CK19, MGB1 and HER2 was measured in CTCs-enriched blood fractions (CTCs-EBF). Results were correlated with each other and with clinico-pathological data of the patients. Results show that the mesenchymal phenotype of CTCs-EBF correlated with poor clinico-pathological characteristics of the patients. Additionally, PT shared more similarities with LNM than with CTCs-EBF. Nevertheless, LNM showed increased expression of EMT-related markers than PT; and EMT itself in PT did not seem to be necessary for lymphatic dissemination.

Markers of circulating breast cancer cells

The detection of circulating tumor cells (CTC) aids in diagnosis of disease, prognosis, disease recurrence, and therapeutic response. The molecular aspects of metastasis are reviewed including its relevance in the identification and characterization of putative markers that may be useful in the detection thereof. Also discussed are methods for CTC enrichment using molecular strategies. The clinical application of CTC in the metastatic disease process is also summarized.

Prognostic value of circulating tumor cells in primary and metastatic breast cancer

In patients with breast cancer, there is evidence correlating the presence of circulating tumor cells (CTCs) with disease-free survival, progression-free survival and overall survival. The detection of CTCs may be useful in gaining a better understanding of the mechanisms of tumor growth and in the improvement of patient management. This review analyzes the prognostic and predictive relevance of CTCs through the principal published studies, cytometric techniques and nucleic acid-based approaches to detect CTCs, phenotypic expression of specific receptors, molecular pathways and genetic signatures for potential tailored therapies.

Prognostic value of circulating tumor cells in nonmuscle invasive bladder cancer: a CellSearch analysis

BACKGROUND

Circulating tumor cells (CTCs) provide prognostic information in patients with metastatic tumors. Recent studies have shown that CTCs are released in circulation in an early phase of cancer disease so that their presence is under investigation in the adjuvant setting. Few studies investigated the prognostic significance of CTCs enumeration in patients with metastatic and advanced bladder cancer. The current study has analyzed the presence of CTC in patients with nonmuscle-invasive bladder cancer (NMIBC).

PATIENTS AND METHODS

Forty-four NMIBC patients were enrolled and included in a 24-month follow-up program. Blood drawings were carried out in all patients at the first diagnosis. CellSearch system (Veridex; LLC, Raritan, NJ) was used for CTCs enumeration.

RESULTS

CTC were detectable in 8/44 patients (18%). Presence of CTC was found significantly associated to shorter time to first recurrence (6.5 versus 21.7 months, P < 0.001). Median time to progression was not reached, due to the short follow-up period. CTC presence was found associated to concomitant carcinoma in situ and higher T category.

CONCLUSION

The detection of CTC in this setting of disease may allow to distinguish patients with high risk of recurrence from those with high risk of progression, as well as to early identify patients candidate for adjuvant treatment.

Clinical implications of the detection of circulating tumor cells in breast cancer patients

The detection of disseminated tumor cells in bone marrow is a common phenomenon seen in 30-40% of primary breast cancer patients. The presence of disseminated tumor cells at diagnosis as well as the persistence of disseminated tumor cells is strongly associated with poor clinical outcome. Since bone marrow biopsies are not well tolerated by many patients, the evaluation of circulating tumor cells in the blood might become a desired alternative. Circulating tumor cells are routinely detected, depending on stage of the disease and methodology, in 10-80% of breast cancer patients. Recent studies have shown a prognostic potential of circulating tumor cells in both primary and metastatic settings. The evaluation of circulating tumor cells may become one of the crucial markers for prediction of survival and therapy monitoring, and its characterization might enable specific targeting of minimal residual, and metastatic disease.

Clinical utility of serum tumor markers and circulating tumor cell assays in the treatment of breast cancer

OPINION STATEMENT

Though serum tumor markers and circulating tumor cells (CTCs) have been available to the oncologist for many years, their place in the management of breast cancer remains unclear. Due to issues with sensitivity and specificity, tumor markers are unreliable for the detection of metastases in early stage breast cancer. For patients with metastatic breast cancer without measurable disease (e.g., bone-only disease, pleural effusions, or ascites), it is reasonable to obtain baseline values of serum tumor markers and attempt to correlate them with the first set of scans. In patients with elevated markers at baseline whose tumor marker levels decrease in correlation with an improvement in clinical symptoms, it may be reasonable to use them in conjunction with imaging to help determine whether there is progression of disease. CTCs have been found to hold strong prognostic value for breast cancer in both the early stage and metastatic settings. No large prospective studies to date, however, have shown any predictive value for CTCs and their clinical utility is therefore limited. Whether changing treatment in response to an increase in CTCs without radiologic progression results in improvements in quality of life or survival remains to be seen. CTCs hold great promise in the management of breast cancer and future studies will help delineate their role more appropriately.

DTCs/CTCs in breast cancer: five decades later

Since circulating tumor cells were first reported in 1955, the field has seen major advances in their detection and has established their prognostic impact. Here we review the current evidence for the prognostic and predictive value of circulating tumor cells in metastatic breast cancer. We then evaluate the role of CTCs and DTCs in early stage breast cancer. The weight of the evidence supports the role of CTCs and DTCs as prognostic indicators, however their role in therapy prediction remains unclear. Ongoing trials may provide answers and newer detection methods which improve sensitivity and specificity may have greater impact. At this point, the data does not support incorporation into clinical practice for early breast cancer patients.

Circulating tumour cells, their role in metastasis and their clinical utility in lung cancer

Circulating tumour cells (CTCs) have attracted much recent interest in cancer research as a potential biomarker and as a means of studying the process of metastasis. It has long been understood that metastasis is a hallmark of malignancy, and conceptual theories on the basis of metastasis from the nineteenth century foretold the existence of a tumour "seed" which is capable of establishing discrete tumours in the "soil" of distant organs. This prescient "seed and soil" hypothesis accurately predicted the existence of CTCs; microscopic tumour fragments in the blood, at least some of which are capable of forming metastases. However, it is only in recent years that reliable, reproducible methods of CTC detection and analysis have been developed. To date, the majority of studies have employed the CellSearch™ system (Veridex LLC), which is an immunomagnetic purification method. Other promising techniques include microfluidic filters, isolation of tumour cells by size using microporous polycarbonate filters and flow cytometry-based approaches. While many challenges still exist, the detection of CTCs in blood is becoming increasingly feasible, giving rise to some tantalizing questions about the use of CTCs as a potential biomarker. CTC enumeration has been used to guide prognosis in patients with metastatic disease, and to act as a surrogate marker for disease response during therapy. Other possible uses for CTC detection include prognostication in early stage patients, identifying patients requiring adjuvant therapy, or in surveillance, for the detection of relapsing disease. Another exciting possible use for CTC detection assays is the molecular and genetic characterization of CTCs to act as a "liquid biopsy" representative of the primary tumour. Indeed it has already been demonstrated that it is possible to detect HER2, KRAS and EGFR mutation status in breast, colon and lung cancer CTCs respectively. In the course of this review, we shall discuss the biology of CTCs and their role in metastagenesis, the most commonly used techniques for their detection and the evidence to date of their clinical utility, with particular reference to lung cancer.

Organ-specific markers in circulating tumor cell screening: an early indicator of metastasis-capable malignancy

Circulating tumor cells (CTCs) represent an important biological link in the spread of primary solid tumors to the metastatic disease responsible for most cancer mortality. Their detection in the peripheral blood of patients with many different carcinomas has shown that tumor-cell dissemination can proceed at an early stage of tumor development and their presence is associated with poor clinical outcomes, particularly in metastatic disease. In this article we describe how the increasingly sensitive isolation and detailed molecular characterization of CTCs has greatly improved our understanding of metastatic proliferation. We focus on how CTC detection and knowledge of the molecular architecture of these cells can serve as biomarkers to signal metastasis-capable disseminating cells and predict therapy-specific response. This has marked clinical utility for improved selection of systemic therapies to the individual needs of a cancer patient, real-time monitoring of metastatic disease treatments and the development of new targeted therapies.

Chemotaxis in cancer

Chemotaxis of tumour cells and stromal cells in the surrounding microenvironment is an essential component of tumour dissemination during progression and metastasis. This Review summarizes how chemotaxis directs the different behaviours of tumour cells and stromal cells in vivo, how molecular pathways regulate chemotaxis in tumour cells and how chemotaxis choreographs cell behaviour to shape the tumour microenvironment and to determine metastatic spread. The central importance of chemotaxis in cancer progression is highlighted by discussion of the use of chemotaxis as a prognostic marker, a treatment end point and a target of therapeutic intervention.

The influence of removal of primary tumor on incidence and phenotype of circulating tumor cells in primary breast cancer

Recent studies have shown that the detection of circulating tumor cells (CTC) pre and postoperatively in the peripheral blood of primary breast cancer patients may be an indicator for poor survival. This study aimed to investigate the influence of removal of the primary tumor on incidence and phenotype of circulating tumor cells in primary breast cancer. 209 primary breast cancer patients could be included into this analysis. Blood sampling was performed both pre and postoperatively. The blood specimens were immunomagnetically enriched using AdnaTest BreastCancerSelect within 4 h after blood withdrawal, followed by RNA isolation and subsequent gene expression analysis by reverse transcription and multiplex PCR using AdnaTest BreastCancerDetect. Three breast cancer-associated tumor markers and two hormone receptor genes were amplified: GA733-2, Muc-1, Her-2, ER, PR. In addition, bone marrow (BM) status was intraoperatively determined. Forty-three of 209 patients (21%) had pre and/or postoperatively circulating tumor cells. The positivity rates after surgery were higher but did not differ significantly (12% pre and 16% postoperatively, P = 0.264). Disseminated tumor cells in BM were seen in 32 of 209 cases (15%). Patients with positive BM status had significantly higher CTC positivity rates both pre and postoperatively compared to those with negative BM status. The most common CTC phenotype was triple negative (24 patients) followed by HER2+/ER-/PR- subtype (10) and ER and/or PR positive (9). Interestingly, 41 of 43 primary tumors (95%) were ER and PR positive. Removal of the primary tumor did not alter the phenotype of CTC. Surgery does not significantly influence the tumor cell load in the blood stream. CTC phenotype before and after the surgery generally remains identical but may differ from that of the primary tumor.

Circulating tumour cells in the central and the peripheral venous compartment in patients with metastatic breast cancer

Background:

The enumeration of circulating tumour cells (CTC) has prognostic significance in patients with metastatic breast cancer (MBC) and monitoring of CTC levels over time has considerable potential to guide treatment decisions. However, little is known on CTC kinetics in the human bloodstream.

Methods:

In this study, we compared the number of CTC in both 7.5 ml central venous blood (CVB) and 7.5 ml peripheral venous blood (PVB) from 30 patients with MBC starting with a new line of chemotherapy.

Results:

The number of CTC was found to be significantly higher in CVB (median: 43.5; range: 0–4036) than in PVB (median: 33; range: 0–4013) (P=0.001). When analysing samples pairwise, CTC counts were found to be significantly higher in CVB than in PVB in 12 out of 26 patients with detectable CTC. In contrast, only 2 out of 26 patients had higher CTC counts in PVB as compared with CVB, whereas in 12 remaining patients no significant difference was seen. The pattern of CTC distribution was independent of the sites of metastatic involvement.

Conclusion:

A substantial difference in the number of CTC was observed between CVB and PVB of patients with MBC. Registration of the site of blood collection is warranted in studies evaluating the role of CTC assessment in these patients.

Circulating tumor cells in breast cancer patients: an evolving role in patient prognosis and disease progression

In this paper, we examine the role of circulating tumor cells (CTCs) in breast cancer. CTCs are tumor cells present in the peripheral blood. They are found in many different carcinomas but are not present in patients with benign disease. Recent advances in theories regarding metastasis support the role of early release of tumor cells in the neoplastic process. Furthermore, it has been found that phenotypic variation exists between the primary tumor and CTCs. Of particular interest is the incongruency found between primary tumor and CTC HER2 status in both metastatic and early breast cancer. Overall, CTCs have been shown to be a poor prognostic marker in metastatic breast cancer. CTCs in early breast cancer are not as well studied, however, several studies suggest that the presence of CTCs in early breast cancer may also suggest a poorer prognosis. Studies are currently underway looking at the use of CTC level monitoring in order to guide changes in therapy.

Advancing personalized cancer therapy by detection and characterization of circulating carcinoma cells

Early dissemination, blood circulation, or homing of single tumor cells in bone marrow and other organs is usually undetectable at primary diagnosis, even by high resolution imaging technologies. However, ultrasensitive approaches now enable the detection of "occult" tumor cells. Many researchers are currently focusing on circulating tumor cells (CTC) in peripheral blood, and several publications have described associations of CTC in patients with metastatic cancer and worse prognosis. However, evidence has emerged that the currently used detection methods lack sensitivity or specificity to track all CTC, especially those that have lost characteristic epithelial features. Therefore, new developments in this field are of utmost interest and will be reviewed here. Moreover, molecular CTC analysis will provide insights into the selection of tumor cells and resistance mechanisms in patients undergoing systemic therapies. This information might support assessing individual prognosis, stratifying patients at risk to systemic therapies, and monitoring therapeutic efficacy.

Molecular mechanisms of metastasis in breast cancer--clinical applications

The metastatic cascade is a series of biological processes that enable the movement of tumor cells from the primary site to a distant location and the establishment of a new cancer growth. Circulating tumor cells (CTCs) have a crucial role in tumor dissemination. The role of CTCs in treatment failure and disease progression can be explained by their relation to biological processes, including the epithelial-to-mesenchymal transition and 'self seeding', defined as reinfiltration of the primary tumor or established metastasis by more aggressive CTCs. CTCs are a unique and heterogeneous cell population with established prognostic and predictive value in certain clinical situations. The possibility of collecting sequential blood samples for real-time monitoring of systemic-therapy efficacy presents new possibilities to evaluate targeted therapies based on the genomic profiling of CTCs and to improve the clinical management of patients by personalized therapy. Interruption of the metastatic cascade via the targeting of CTCs might be a promising therapeutic strategy.

Circulating tumour cells in cancer patients: challenges and perspectives

Ultrasensitive methods have been recently developed to detect circulating tumour cells (CTCs) in the peripheral blood and disseminated tumour cells (DTCs) in the bone marrow (BM) of cancer patients. Studies with these new methods indicate that BM is a common homing organ and a reservoir for DTCs derived from various organ sites including breast, prostate, lung and colon. Peripheral blood analyses, however, are more convenient for patients than invasive BM sampling and many research groups are currently assessing the clinical utility of CTCs for prognosis and monitoring response to systemic therapies. Moreover, molecular analyses of CTCs/DTCs have provided new insights into the biology of metastasis with important implications for the clinical management of cancer patients.