Prognostic significance of reverse transcriptase-polymerase chain reaction measurement of carcinoembryonic antigen mRNA levels in tumor drainage blood and peripheral blood of patients with colorectal carcinoma

Diversity of assessing circulating tumor cells (CTCs) emphasizes need for standardization: a CTC Guide to design and report trials

Hematogenous spreading of tumor cells from primary tumors is a crucial step in the cascade to metastasis, the latter being the most limiting factor for patients' survival prognosis. Therefore, circulating tumor cells (CTCs) have become a field of intensive research. However, the process of isolation and identification of CTCs lacks standardization. This article presents an overview of 71 CTC studies reported in PUBMED since 2000 and focusing on colorectal cancer. These studies are evaluated regarding standardization of CTC isolation and identification, marker proteins used, study population and blood sample quality management, clinical performance, and quality measures. Overall, standardization of CTC assessment seems insufficient. Thus, comparability of CTC studies is hampered and results should be interpreted carefully. We here propose a standardized CTC guideline (CTC Guide) to prospectively design and report studies/trials in a harmonized form. Despite the current interstudy heterogeneity, the data indicate that CTC detection is of clinical relevance and CTCs should be considered as a surrogate prognostic marker. Many studies indicate the high potential for CTCs as prognostic markers, e.g., in colorectal cancer treatment. However, standardized, large-scale multicenter validation studies are still needed to pave the way for clinical implementation of CTC detection that could ameliorate individualized medicine regimes.

Meta-analysis of the prognostic value of circulating tumor cells detected with the CellSearch System in colorectal cancer

BACKGROUND

The prognostic value of circulating tumor cells (CTCs) detected with the CellSearch System in patients with colorectal cancer (CRC) is controversial. The aim of our meta-analysis was to evaluate whether the detection of CTCs in the peripheral blood with the standardized CellSearch System has prognostic utility for patients with CRC.

METHODS

The PubMed, Science Citation Index, Cochrane Database, Embase, and the references in relevant studies were systematically searched (up to December, 2014). No search restrictions were imposed. Our meta-analysis was performed in Stata software, version 12.0 (2011) (Stata Corp, College Station, TX, USA), with the odds ratio (OR), risk ratio (RR), hazard ratio (HR), and 95% confidence interval (95% CI) as the effect measures. Subgroup and sensitivity analyses were also conducted.

RESULTS

Eleven studies containing 1847 patients with CRC were analyzed. There was a significantly higher incidence of CTCs in the metastasis-positive group than in the metastasis-negative group (OR = 4.06, 95% CI [1.74, 9.50], P < 0.01, I(2) = 0%). For hepatic metastasis, a type of metastasis, a higher incidence of CTCs was observed in the hepatic-metastasis-positive group than in the -negative group (OR = 2.61, 95% CI [1.73, 3.96], P < 0.01, I(2) = 0%). The presence of CTCs was significantly related to overall survival (HR = 2.00, 95% CI [1.49, 2.69], P < 0.01, I(2) = 67.1%) and progression-free survival (HR = 1.80, 95% CI [1.52, 2.13], P < 0.01, I(2) = 43.9%) of patients with CRC, regardless of the sampling time. The response rate for the CTC(+) groups was significantly lower than that for the CTC(-) groups at baseline and during treatment (baseline: 33% versus 39%, RR = 0.79, 95% CI [0.63, 0.99], P = 0.04, I(2) = 7.0%; during treatment: 17% versus 46%, RR = 0.41, 95% CI [0.22, 0.77], P = 0.01, I(2) = 0.0%;).

CONCLUSIONS

Our meta-analysis indicates that the detection of CTCs in the peripheral blood with the CellSearch System has prognostic utility for patients with CRC.

Detection of carcinoembryonic antigen mRNA in peritoneal lavage by the transcription-reverse transcription concerted method indicates poor prognosis in patients with stage II and III colon cancer

BACKGROUND

Peritoneal dissemination and positive peritoneal lavage cytology are associated with poor prognosis in colorectal cancer. Carcinoembryonic antigen (CEA) messenger RNA (mRNA) is often used as a marker to detect micrometastases. We aimed to evaluate the prognostic significance of CEA mRNA in the peritoneal lavage of colon cancer patients.

METHODS

Colon cancer patients (n = 201) who underwent curative operative resection between August 2009 and February 2013 were enrolled. CEA mRNA in peritoneal lavage was measured using the transcription-reverse transcription concerted method, a quantitative RNA amplification method. The correlation between CEA mRNA and overall and peritoneal recurrence-free survival was evaluated.

RESULTS

Positive CEA mRNA in peritoneal lavage was an independent risk factor for overall recurrence-free survival in colon cancer (P < .0001). Positive CEA mRNA was a risk factor for poorer overall recurrence in stage II and III patients (P = .04 and P = .02, respectively). Moreover, among stage III patients with positive CEA mRNA, the postoperative chemotherapy group had significantly lower overall and peritoneal recurrence rates than the no postoperative chemotherapy group (P = .001).

CONCLUSION

Positive CEA mRNA in peritoneal lavage was associated with high overall recurrence rates in stage II and III colon cancer. Further study is necessary to determinate the efficacy of aggressive postoperative chemotherapy for stage II and III colon cancer patients with positive CEA mRNA.

Prognostic significance of isolated tumor cells in patients with colorectal cancer in recent 10-year studies

Circulating tumor cells (CTCs) that detach from the primary tumor and move into the circulation are detected in patients with metastatic cancer. The discovery of such cancer cells has been used as a predictor of recurrence and prognosis, although a consensus regarding such applications has not been reached. Peritoneal cytology may be used for identifying high risk of recurrence or mortality, whereas the intraoperative presence of tumor cells in drainage veins, bone marrow, or the liver is not always useful for evaluating the prognosis. The reported positive rate for tumor cells in the peripheral blood of patients with colorectal cancer, including metastasis, has varied from 10 to 80%; however, numerous studies have demonstrated significant differences in the recurrence and mortality rates between patients with and without isolated tumor cells (ITCs) in the peripheral blood. However, the clinical significance of CTCs as an absolute prognostic factor has not been elucidated, since the measurement methodologies and/or the number of cases differed between the studies. Future prospective studies including larger patient populations may elucidate the utility of routine detection of ITCs in daily practice.

Investigation of free cancer cells in peripheral blood using CEA mRNA expression in perioperative colorectal cancer patients

The aim of this study was to evaluate the impact of laparoscopic surgery (Lap) on circulating free tumor cells in colorectal cancer patients. In this study, we selected carcinoembryonic antigen (CEA) mRNA expression in peripheral blood as the marker of the circulating tumor cells and compared this marker between Lap and open colectomy (OC), to investigate differences due to surgical approach. A total of 50 patients underwent curative surgery for solitary colorectal cancer at our department, between June, 2008 and February, 2011. The patients were divided into OC and Lap groups (25 patients each). Total RNA was extracted subsequent to peripheral blood collection prior to surgery, immediately following surgery and 1, 3 and 7 days after surgery. CEA mRNA was detected with reverse transcription polymerase chain reaction (RT-PCR) and the association between peripheral blood CEA mRNA-positive rate, surgical findings and clinicopathological characteristics was investigated. The peripheral blood CEA mRNA-positive rate was significantly increased immediately after surgery, compared to the preoperative rate (P=0.001), but decreased over time. No significant differences were observed at any blood-sampling time point after postoperative day 1. The positive rate was significantly increased in the OC group immediately after surgery, compared to the preoperative rate (P=0.004). However, there were no significant differences between the rates prior to and immediately after surgery in the Lap group. The patients were then divided into those who were peripheral blood CEA mRNA-positive and -negative after surgery (postoperative positive and negative groups, respectively) and the clinicopathological characteristics were compared. Significant differences were identified between the groups in lower rectal cancer patients and patients with a large intraoperative blood loss (P=0.001 and P=0.01, respectively). In conclusion, in colorectal cancer patients, there were no significant differences in the perioperative peripheral blood CEA mRNA-positive rate or its short-term changes between patients undergoing OC and Lap surgery. It was suggested that Lap is equivalent to OC with regard to free cancer cells.

Compartmental differences of circulating tumor cells in colorectal cancer

BACKGROUND

The prognostic role of circulating tumor cells (CTCs) has been established for colorectal cancer (CRC). We investigated the qualitative and quantitative detection of CTC in the central (CVBC) and mesenteric (MVBC) venous blood compartments to elucidate the patterns of hematogenous tumor cell dissemination in patients with CRC.

METHODS

A total of 200 patients were enrolled prospectively. Blood samples were collected from the tumor-draining vein and via a central venous line. CTCs were detected and quantified by using the CellSearch system. Factors associated with CTC detection in both compartments were analyzed by using univariate and multivariate analyses.

RESULTS

CTC analyses were performed in the CVBC and MVBC in 200 and 80 patients, respectively. CTCs were found at a higher rate (P=0.01) and at a higher count (P=0.006) in the MVBC compared with the CVBC. On multivariate analyses, stage IV disease (odds ratio, 3.83; 95% confidence interval, 1.42-10.35) and increased preoperative carbohydrate antigen 19-9 level (odds ratio, 3.57; 1.30-9.79) were associated with CTC detection in the CVBC. CTCs were detected more frequently (P=0.05) and at higher numbers (P=0.05) in the CVBC of patients with low compared with mid or high rectal tumors.

CONCLUSIONS

The qualitative and quantitative detection of CTCs is higher in the MVBC compared with the CVBC of patients with CRC.

Meta-analysis shows that detection of circulating tumor cells indicates poor prognosis in patients with colorectal cancer

BACKGROUND & AIMS

The prognostic significance of circulating (CTCs) and disseminated tumor cells in patients with colorectal cancer (CRC) is controversial. We performed a meta-analysis of available studies to assess whether the detection of tumor cells in the blood and bone marrow (BM) of patients diagnosed with primary CRC can be used as a prognostic factor.

METHODS

We searched the Medline, Biosis, Science Citation Index, and Embase databases and reference lists of relevant articles (including review articles) for studies that assessed the prognostic relevance of tumor cell detection in the peripheral blood (PB), mesenteric/portal blood (MPB), or BM of patients with CRC. Meta-analyses were performed using a random effects model, with hazard ratio (HR) and 95% confidence intervals (95% CIs) as effect measures.

RESULTS

A total of 36 studies, including 3094 patients, were eligible for final analyses. Pooled analyses that combined all sampling sites (PB, MPB, and BM) associated the detection of tumor cells with poor recurrence-free survival (RFS) (HR = 3.24 [95% CI: 2.06-5.10], n = 26, I(2) = 77%) and overall survival (OS) (2.28 [1.55-3.38], n = 21, I(2) = 66%). Stratification by sampling site showed that detection of tumor cells in the PB compartment was a statistically significant prognostic factor (RFS: 3.06 [1.74-5.38], n = 19, I(2) = 78%; OS: 2.70 [1.74-4.20], n = 16, I(2) = 59%) but not in the MPB (RFS: 4.12 [1.01-16.83], n = 8, I(2) = 75%; OS: 4.80 [0.81-28.32], n = 5, I(2) = 82%) or in the BM (RFS: 2.17 [0.94-5.03], n = 4, I(2) = 78%; OS: 1.50 [0.52-4.32], n = 3, I(2) = 84%).

CONCLUSION

Detection of CTCs in the PB indicates poor prognosis in patients with primary CRC.

Circulating tumour cell analysis as an early marker for relapse in stage II and III colorectal cancer patients: a pilot study

INTRODUCTION

Recent studies have identified both the prognostic and predictive utility of determining the number of circulating tumour cells (CTC) in patients with solid cancers.

MATERIAL AND METHODS

In the present pilot study we evaluated the ability of two different methods to isolate CTC in combination with two strategies to enumerate CTC from patients with stages II and III surgically treated colorectal cancer (CRC). First, we used two systems for tumour cell enrichment (differential centrifugation and immunomagnetic beads), combined with two methods to enumerate CTC (real-time PCR and fl ow cytometry), to determine the most efficient combination. These experiments were performed in a model system using serial dilutions of HT29 tumour cell lines with lymphocytes. Then, CTC analysis using the technical approach selected before was performed in 109 blood samples from 16 stage II and III CRC patients during chemotherapy treatment and follow-up.

RESULTS

Immunomagnetic beads followed by flow cytometry was the most efficient combination (ED=60.53; p=0.5). Two cases out of 16 patients analysed had clinical tumour relapse. In both, we detected a significant increase of CTC five and six months, respectively, before the relapse was clinically evidenced. An increase of CTC was also observed in another case without clinical evidence of relapse. The remaining cases (13) had very few or no detectable CTC and no clinical evidence of relapse (p=0.029).

CONCLUSIONS

Changes in CTC numbers during follow-up might predict tumour relapse. Further evaluation of CTC prognostic and predictive value in patients with early CRC is warranted.

Prognostic significance of circulating tumour cells following surgical resection of colorectal cancers: a systematic review

Background:

The role of adjuvant chemotherapy after resection of colorectal cancers (CRCs) is well understood for patients with stage-I or stage-III disease. Its efficacy for those with stage-II disease remains much less clear. Many investigators have sought to identify prognostic markers that might clarify which patients have the highest risk of recurrence and would, therefore, be most likely to benefit from chemotherapy. This systematic review examines evidence for the use of peripherally sampled, circulating tumour cells (CTCs) as such a prognostic marker.

Methods:

A comprehensive literature search was used to identify studies reporting on the significance of CTCs in the postoperative blood of CRC patients.

Results:

Fourteen studies satisfied the inclusion criteria. Six of the nine studies that took blood samples 24 h or more postoperatively found detection of postoperative CTCs to be an independent predictor of cancer recurrence.

Conclusion:

The presence of CTCs in peripheral blood at least 24 h after resection of CRCs is an independent prognostic marker of recurrence. Further studies are needed to clarify the optimal time point for blood sampling and determine the benefit of chemotherapy in CTC-positive patients with stage-II disease.

Cancer stemness and metastasis: therapeutic consequences and perspectives

The transient and dynamic nature of cancer cells that underlie metastasis cannot only be explained by the progressive accumulation of irreversible genetic changes occurring in the primary tumour. The capacity of cells to switch between different cellular identities, as in epithelial to mesenchymal (EMT) and mesenchymal to epithelial transitions (MET), allows them to respond to different cellular environments, thus efficiently disseminating from the primary mass to eventually colonise distant organs. These more dynamic stem-like cancer cells are earmarked by the ability to self-renew and de-/re-differentiate, and eventually recapitulate the heterogeneous composition of the primary tumour in a distant organ site. This dynamic concept of metastasis has profound consequences and implications for cancer diagnostics, prognostics and therapy. Many of the characteristics that define stem cells, like dormancy, active DNA repair, the expression of several drug transporters, and resistance to apoptosis may underlie the capacity of migrating cancer cells to survive conventional therapeutic protocols based on genotoxic agents targeting active proliferating cells. Accordingly, signal transduction pathways that regulate the balance between self-renewal and differentiation are likely to represent future targets in the development of tailor-made intervention strategies. Also, specific stem cell features, such as the capacity to migrate to diseased areas (pathotropism), open novel avenues towards the development of cell vehicles capable of tracking and delivering anti-cancer compounds to disseminated metastatic lesions.

Circulating tumor cells: evolving evidence and future challenges

Circulating tumor cells (CTCs) are rare malignant cells found in the peripheral blood that originate from the primary tumor or metastatic sites. New techniques have been developed to isolate and characterize these cells. CTC enumeration has been incorporated into different fields of oncology as a prognostic marker, a tool to monitor therapy response, and a method to understand basic tumor characteristics. This review covers the different techniques available for isolation of CTCs, the clinical utility of CTCs in breast, prostate, and colon cancer, and future directions in this field.

Circulating tumour cells during laparoscopic and open surgery for primary colonic cancer in portal and peripheral blood

BACKGROUND

The objective of this study was to detect and quantify circulating tumour cells (CTC) in peripheral and portal blood of patients who had open or laparoscopic surgery for primary colonic cancer.

METHODS

Patients in the laparoscopic-group were operated on in a medial to lateral approach ("vessels first"), in the open-group a lateral to medial approach was applied. The enumeration of CTC was performed with the CellSearch System. Intra-operative samples were taken paired-wise (from peripheral and portal circulation) directly after entering the abdominal cavity (T1), after mobilisation of the tumour baring segment (T2), and after tumour resection (T3). Ploidy of both the CTC and tissue of the primary tumour was determined for chromosome 1, 7, 8 and 17.

RESULTS

Thirty-one patients were included; 18 patients had open surgery, 13 patients were operated on laparoscopically. The percentage of samples with CTC at T1 was 7% in peripheral blood and 54% in portal blood (p=0.002). At T2, 4% and 31% respectively (p=0.031). And at T3, 4% and 26% respectively (p=0.125). The cumulative percentage of samples with CTC was significantly higher during open surgery as compared to the laparoscopic approach. Both the CTC and tissue of the primary tumour were diploid for chromosome 1, 7, 8 and 17.

CONCLUSION

The detection rate and quantity of CTC is significantly increased intra-operatively and is significantly higher in portal blood compared to peripheral blood. Significantly less CTC were detected during laparoscopic surgery probably as result of the medial to lateral approach.

DETECTION OF DISSEMINATED TUMOR CELLS IN PERIPHERAL BLOOD

Metastases are the major cause of cancer-related deaths in patients with solid epithelial malignancies, such as breast, colorectal and prostate carcinomas. Hematogenous spreading of tumor cells from a primary tumor can be considered as a crucial step in the metastasis cascade leading eventually to the formation of clinically manifest metastases. Consequently, as shown in recent studies, the detection of disseminated tumor cells in peripheral blood might be of clinical relevance with respect to individual patient prognosis and staging or monitoring of therapy. However, the rarity of disseminated tumor cells in peripheral blood renders the application of sensitive techniques mandatory for their detection. The emergence of highly sophisticated reverse transciptase-polymerase chain reaction (RT-PCR) assays, combining a preanalytical enrichment step with the assessment of multiple molecular tumor markers expressed in disseminated tumor cells, provides a powerful tool in detecting disseminated tumor cells with high sensitivity and specificity. This review will discuss currently used tumor markers as well as experimental means to enhance the sensitivity and specificity of RT-PCR assays to detect disseminated tumor cells in the peripheral blood of patients with breast, colorectal, and prostate cancers, and their clinical relevance assessed in recent studies.

Does the presence of circulating tumor cells in the venous drainage of curative colorectal cancer resections determine prognosis? A meta-analysis

BACKGROUND

Hepatic metastasis can occur following curative colorectal cancer surgery despite favorable prognostic indicators, raising the question of whether detecting circulating tumor cells in the venous drainage of colorectal cancers at resection using reverse-transcriptase polymerase chain reaction would help determine prognosis. This study compares lymph node positivity, hepatic metastasis rates, and disease-free survival in circulating tumor positive versus negative patients.

METHODS

A Medline, Embase, Ovid, and Cochrane database search was conducted on all studies between 1999 and 2006 reporting the outcomes of interest. Meta-analysis was performed in line with recommendations from the Cochrane Collaboration and the Quality of Reporting of Meta-Analyses guidelines.

RESULTS

Nine studies reporting on 646 subjects published between 1998 and 2006 matched the selection criteria and were suitable for inclusion in this meta-analysis. There was a significantly higher incidence of circulating tumor cells (50%) in lymph node positive compared with negative groups (21%) [odds ratio (OR) = 3.83, confidence interval (CI) = 2.46-5.94], and a significantly increased hepatic metastases rate (21%) in circulating tumor cells positive compared with in negative patients (8%, OR = 6.38; CI = 2.67-15.25. Disease-free survival was significantly higher in the circulating tumor cell negative versus positive groups at 1 year [hazard ratio (HR) = 0.04, CI = 0-0.46], 2 years (HR = 0.05, CI = 0.01-0.31), and 3 years (HR = 0.08, CI = 0.02-0.34) post resection.

CONCLUSION

This study highlights the potential importance of free cancer cell detection in the venous drainage of colorectal cancers as a prognostic indicator and a mode of staging colorectal cancers.

Quantitative RT-PCR detection of colorectal tumor cells in peripheral blood--a systematic review

BACKGROUND

Twenty percent to 40% of patients with node-negative colorectal cancer die of metastatic disease. Detection of cancer cell dissemination has been proposed as a tool to select patients at highest risk for recurrence. In this review, we summarize the evidence for detection with quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assays of circulating tumor cells (CTCs) in peripheral blood of colorectal cancer patients.

MATERIALS AND METHODS

Pubmed and Embase were systematically searched for all English publications relevant to circulating cancer cells, peripheral blood, quantitative RT-PCR (q-RT-PCR), and colorectal cancer. Cross-references and the "related articles" function were used to broaden the search. Manuscripts reporting on the results of nonquantitative RT-PCR assays were excluded. The study methodology, CTCs detection rates in peripheral blood, and prognostic value were reviewed.

RESULTS

Twelve manuscripts on qRT-PCR were retrieved. Stage dependence was found for detection of CTCs in four of 10 studies. From univariate analysis performed for disease-free survival and overall survival in 4 of 12 studies, there was evidence (P < 0.05) for an effect of the detection of CTCs with qRT-PCR. None of the included trials identified detection of CTCs in peripheral blood as an independent predictor of survival.

CONCLUSION

Quantification of CTCs in peripheral blood holds promise in predicting stage and outcome in colorectal cancer patients. At present, evidence from the literature is too scarce to integrate quantitative RT-PCR assays to detect CTCs into the management of colorectal cancer.

Isolated tumour cells in blood and E-cadherin expression in oesophageal squamous cell cancer

BACKGROUND

Patients with oesophageal squamous cell carcinoma have a high rate of recurrence, even after curative resection. The aim of this study was to examine the correlation between the presence of isolated tumour cells (ITCs) in the blood and recurrence, and between the presence of ITCs and E-cadherin expression in the primary tumour in these patients.

METHODS

Blood samples obtained immediately before and after resection in 125 patients with oesophageal squamous cell carcinoma were examined by real-time reverse transcription-polymerase chain reaction using carcinoembryonic antigen mRNA. Blood samples from 28 healthy volunteers and 42 patients with benign diseases were used as controls.

RESULTS

Seventy-seven patients (61.6 per cent) were ITC positive. ITC positivity correlated significantly with tumour depth, lymph node metastasis, stage, lymphatic invasion and venous invasion. Multivariable analysis revealed that tumour depth and ITC positivity were independent factors for a shortened haematogenous disease-free interval. A significant correlation was found between ITC positivity and reduced E-cadherin expression in the primary tumour (P < 0.001). ITC-positive patients with preserved E-cadherin expression had a longer disease-free interval (P = 0.016), haematogenous disease-free interval (P = 0.020) and overall survival (P = 0.004) than those with reduced E-cadherin expression.

CONCLUSION

Examination of ITCs in the blood is useful for predicting haematogenous recurrence in patients with oesophageal squamous cell carcinoma.

Guanylyl cyclase C: a molecular marker for staging and postoperative surveillance of patients with colorectal cancer

Staging patients with colorectal cancer defines their prognosis and therapeutic management. Unfortunately, histopathology, the current standard for staging, is relatively insensitive for detecting occult micrometastases and a significant fraction of patients are understaged and, consequently, undertreated. Similarly, current approaches to postoperative surveillance of patients with colorectal cancer detect disease recurrence at a point when interventions have little impact on survival. The detection of rare cells in tissue, for accurately staging patients, and in blood, for detecting disease recurrence, could be facilitated by employing sensitive and specific markers of disease. Guanylyl cyclase C (GCC), the receptor for the diarrheagenic bacterial heat-stable enterotoxin, is expressed selectively by cells derived from intestinal mucosa, including normal intestinal cells and colorectal tumor cells, but not by extragastrointestinal tissues and tumors. The nearly uniform expression of relatively high levels by metastatic colorectal tumors suggests that GCC may be a sensitive and specific molecular marker for metastatic colorectal cancer cells. Employing GCC reverse transcriptase PCR, occult colorectal cancer micrometastases were detected in lymph nodes that escaped detection by histopathology. Moreover, marker expression correlated with the risk of disease recurrence. Similarly, GCC reverse transcriptase PCR revealed the presence of tumor cells in blood of all patients examined with metastatic colorectal cancer and, in some studies, was associated with an increased risk of disease recurrence and mortality. These observations suggest that GCC reverse transcriptase PCR is a sensitive and specific technique for identifying tumor cells in extraintestinal sites and may be useful for staging and postoperative surveillance of patients with colorectal cancer.

Detection of carcinoembryonic antigen messenger RNA-expressing cells in peripheral blood 7 days after curative surgery is a novel prognostic factor in colorectal cancer

BACKGROUND

The significance of detection of circulating cancer cells in blood during surgery in patients with colorectal cancer (CRC) remains controversial. Experimental study revealed that the cancer cells injected from the vein disappeared completely until 7 days. The aim of this study was to clarify that the detection of circulating cancer cells in blood taken later than 7 days after curative surgery may be a prognostic factor.

METHODS

Two hundred consecutive patients with CRC who underwent potentially curative surgery were the subjects. Peripheral blood was collected between 7 and 10 days after resection. Cancer cells were detected using reverse transcriptase-polymerase chain reaction targeting carcinoembryonic antigen (CEA) messenger RNA (mRNA). The median follow-up period was 52 months (range: 34-69 months).

RESULTS

The overall positive incidence of CEA mRNA was 22%. Detection of CEA mRNA was not significantly related to conventional clinicopathological findings. Recurrence has been confirmed in 55 patients (28%). The recurrence rate was significantly higher in patients with rectal cancer, deep penetration, lymph node metastasis, preoperative chemoradiotherapy and positive CEA mRNA. The CEA mRNA positive patients showed significantly poorer disease free survival (DFS) and overall survival (OS) than the negative patients (DFS, P = 0.007; OS, P = 0.04). Multivariate analysis revealed that the positive expression of CEA mRNA (P < 0.01) as well as the tumor location and TNM stage classification was identified as the significant risk factors for recurrence.

CONCLUSIONS

Detection of CEA mRNA expressing cells in peripheral blood 7 days after curative surgery is a novel independent factor predicting recurrence in patients with CRC.

Disseminated tumor cells in peripheral blood: a novel marker for therapy response in locally advanced rectal cancer patients undergoing preoperative chemoradiation

PURPOSE

This study was designed to examine whether disseminated tumor cells in peripheral blood of locally advanced rectal cancer patients undergoing preoperative chemoradiation have the potential to serve as a marker for therapy response. Studies suggest that patients with advanced rectal cancer who respond to preoperative chemoradiation most likely benefit from this treatment.

METHODS

From advanced rectal cancer patients undergoing preoperative chemoradiation, peripheral blood was obtained at defined times: before, during, and after chemoradiation and during surgery. Patients were divided into histopathologic responders (ypT0-T2) and nonresponders (ypT3-T4). Cytokeratin 20 and carcinoembryonic antigen reverse transcriptase-polymerase chain reaction were performed to detect disseminated tumor cells. A blood sample was deemed positive for disseminated tumor cells if both carcinoembryonic antigen and cytokeratin 20 were detected.

RESULTS

The overall population (n = 26) showed a positivity rate of 32 percent for disseminated tumor cells before initiation of chemoradiation. Of the responders (n = 8), 63 percent were positive for disseminated tumor cells before chemoradiation, whereas only 18 percent of nonresponders (n = 18) were positive (P = 0.026). From initiation of chemoradiation to the end of surgery, a significant decrease was seen in tumor cell positivity in the blood of responders (P = 0.042). Moreover, the responders represented a trend toward a decrease in tumor cell positivity during chemoradiation (P = 0.079). In contrast, there were no noticeable alterations within the treatment course in nonresponders.

CONCLUSIONS

This prospective proof of principle study demonstrates that locally advanced rectal cancer with preoperative chemoradiation shows different biologic behavior in terms of tumor cell dissemination in peripheral blood when therapy responders compared with nonresponders.

Prognostic significance of CEA levels and detection of CEA mRNA in draining venous blood in patients with colorectal cancer

BACKGROUND AND OBJECTIVES

The aims of this study were to determine carcinoembryonic antigen (CEA) levels and incidence of tumor cells using the RT-PCR technique in draining venous blood of patients with colorectal cancer, correlate the results with various histopathologic factors and determine their significance as prognostic factors.

METHODS

From 1995 to 2000, 108 patients with adenocarcinoma of the colon or rectum, underwent curative surgery and enrolled in this prospective study.

RESULTS

The 5-year survival group had significantly lower portal CEA levels compared to the hepatic metastasis outcome group. CEA mRNA was positive in the draining venous blood from 12 (11.1%) out of 108 patients included in the study. The rate of positive tumor cell detection in portal blood was significantly higher in the hepatic metastasis outcome group than in the 5-year survival and recurrence group. The proportion of patients with portal CEA > or =5 ng/ml was greater in patients with higher stage than in patients with lower stage.

CONCLUSIONS

Positive CEA mRNA in draining venous blood predicted hepatic metastases and local recurrence with accuracy over 80% but with low sensitivity of 30% and 9%, respectively. Moreover, CEA level was a sensitive indicator in hepatic metastases as sensitivity was 95% and a specific indicator in predicting 5-year survival with specificity 84%.

Impact of disseminated tumor cells in gastrointestinal cancer

The detection of epithelial cells by sensitive immunological and molecular methods in blood, lymph nodes or bone marrow of gastrointestinal cancer patients may open a new approach to clinical metastasis research. The phenotypic and genomic characterization of these cells is of great value in the prediction of the further course of the disease and the monitoring of response to treatment. In addition, the role of ultrastaging in blood, lymph nodes and bone marrow of cancer patients for the indication of multimodal therapy is discussed in this review. The impact of prognostic or predictive factors for new treatment protocols in patients with gastrointestinal cancer was evaluated as well as the correlation with clinical factors.

Squamous cell carcinoma-antigen messenger RNA level in peripheral blood predicts recurrence after resection in patients with esophageal squamous cell carcinoma

BACKGROUND

The aim of this study was to clarify whether preoperative squamous cell carcinoma-antigen messenger RNA (SCC-Ag mRNA) level in peripheral blood can be used to predict tumor recurrence after curative resection for esophageal squamous cell carcinoma.

METHODS

A prospective analysis was conducted for 46 consecutive patients who underwent curative esophagectomy and who had no residual tumor. The SCC-Ag mRNA level in the peripheral blood of each patient was measured preoperatively by using quantitative reverse transcriptase-polymerase chain reaction. Median follow-up period was 34 months.

RESULTS

Receiver operating characteristic analysis demonstrated that the optimal cutoff level of SCC-Ag mRNA was 40. Patients were divided into the high SCC-Ag mRNA level group (n = 14) and the low SCC-Ag mRNA level group (n = 32). The cumulative probabilities of tumor recurrence were higher in the high SCC-Ag mRNA level group (probability of recurrence was 71% at 2 years) than in the low group (22% at 2 years; P = .0005). SCC-Ag mRNA level (relative risk, 3.00; 95% confidence interval, 1.05-8.54; P = .040) was the strongest independent predictor of recurrence by multivariate analysis.

CONCLUSIONS

Preoperative SCC-Ag mRNA levels in the peripheral blood are the best predictive factor for recurrence in patients with esophageal squamous cell carcinoma who undergo curative resection (R0).

Long-term prognostic value of detection of circulating colorectal cancer cells using CGM2 reverse transcriptase-polymerase chain reaction assay

BACKGROUND

The criteria commonly used for prognosis of colorectal cancer remain histoprognostic and are based on primarily TNM classification. The lack of discrimination of purely histoprognostic criteria is evidenced by the development of different outcomes in similarly staged patients. The aim of this work was to study the long-term prognostic value of preoperative detection of circulating enterocytes in the blood of colorectal cancer patients using the CGM2 reverse transcriptase-polymerase chain reaction (RT-PCR) assay.

METHODS

A nested RT-PCR with specific primers for CGM2 was used preoperatively to detect circulating enterocytes in 121 patients (64 men, 57 women; mean age, 70 years) with colorectal neoplasms.

RESULTS

Circulating enterocytes were detected in 58/121 (48%) patients. The positivity rate was not correlated with American Joint Committee on Cancer (AJCC) staging (stage I, 11/28 (39%); stage II, 13/34 (38%); stage III, 15/23 (65%); stage IV, 17/32 (53%); sterilized (after radiotherapy, no residual neoplasm) 2/4 (50%); not significant [NS]), but circulating enterocytes were detected more frequently in patients with metastatic lymph nodes (60% vs 41%, P = .06). Overall 5-year survival rates (mean +/- SD) were 40 +/- 13% and 45 +/- 13% for patients without and with circulating enterocytes, respectively (P = NS). Similarly, recurrence-free survival rates were 71 +/- 4% versus 72 +/- 14% (P = NS). Using univariate analysis, AJCC stage (P < .0001) was correlated with survival. AJCC stage (P = .007) and obstructive neoplasms (P = .043) were correlated with recurrence-free survival. Using multivariate analysis, AJCC stage was correlated with survival and recurrence-free survival.

CONCLUSIONS

Preoperative detection of circulating enterocytes using CGM2 RT-PCR assay provides no specific prognostic information and cannot be used as a decision criterion for adjuvant therapy.

Value of carcinoembryonic antigen assay in predicting hepatic metastases, local recurrence, and survival after curative resection of colorectal cancer

PURPOSE

We measured carcinoembryonic antigen (CEA) levels in peripheral and portal venous blood, and bile from patients with colorectal cancer, to determine its role in predicting hepatic metastases, local recurrence, and survival.

METHODS

The subjects were 73 patients who underwent curative surgery for colorectal cancer.

RESULTS

The median serum, bile, and portal CEA levels were significantly lower in 5-year survivors than in patients in whom hepatic metastases or recurrent disease subsequently developed. The CEA level in portal blood and bile was a good indicator of hepatic metastases, with sensitivity of 92% and 100%, respectively. However, the accuracy of any CEA measurement for predicting hepatic metastases, local recurrence, or 5-year survival did not exceed 70%.

CONCLUSIONS

None of these CEA measurements is accurate enough to be the basis of a management decision. Thus, we suggest that CEA measurement be used to assist in the prediction of a high risk of the development of hepatic secondaries and that these patients are followed up closely after curative resection.

Detection of carcinoembryonic antigen messenger RNA-expressing cells in portal and peripheral blood during surgery does not influence relapse in colorectal cancer

BACKGROUND

No consensus has been reached on whether cancer cells detected in blood during colorectal cancer (CRC) surgery may serve as a prognostic indicator.

METHODS

One hundred patients with CRC who underwent curative surgery were the subjects. Portal and peripheral blood were collected immediately after celiotomy and examined for carcinoembryonic antigen (CEA) messenger RNA (mRNA) by using competitive semi-nested reverse transcriptase-polymerase chain reaction. The median follow-up period was 59 months (range, 49-74 months).

RESULTS

Until now, recurrence has been confirmed in 13 patients (13%). The 4-year recurrence rate was 6.7% (3 of 45) in patients with CEA mRNA-positive portal blood and 20.8% (10 of 48) in patients with CEA mRNA-negative portal blood (P = .09); it was 5.6% (2 of 36) and 19.3% (11 of 57) in patients with CEA mRNA-positive peripheral blood and CEA mRNA-negative blood, respectively (P = .12). There was no difference in disease-free survival between the CEA mRNA-positive and -negative groups. The multivariate analysis showed that the presence of tumor cells in portal or peripheral blood was a factor that reduced recurrence. The relative risks were .17 (P = .01) for the portal vein and .24 (P = .07) for the peripheral vein.

CONCLUSIONS

The detection of cancer cells in blood taken during surgery is not considered to be a poor-prognostic factor in CRC.

Detection and clinical implications of minimal residual disease in gastro-intestinal cancer

INTRODUCTION

Metastatic dissemination is an important factor for the prognosis of patients with gastro-intestinal cancer. Exact staging is crucial to determine appropriate multimodal therapeutic strategies. At present, the sensitivity of routinely performed diagnostic techniques is suboptimal for the detection of minimal residual disease (MRD) and occult metastases since the number of disseminated tumour cells (DTCs) is mostly marginal. To amend the verification of DTCs, immunohistochemical and molecular methods were applied to retrieve epithelial cell-specific proteins in non-epithelial tissue of different body compartments or fluids. Many groups have eagerly focussed on the identification of new markers and novel tests, yet specificity and sensitivity of these methods as well as robustness in the clinical setting are frequently missing.

MATERIALS AND METHODS

This review critically evaluates the prognostic impact of MRD in patients with pancreatic, colorectal and gastric cancer by outlining those studies showing diagnostic results of DTC detection in lymph nodes, bone marrow, venous blood and peritoneal lavage, some of which present novel strategies.

CONCLUSION

The analysed data concerning MRD in gastro-intestinal cancers reveal that results are undesirably heterogeneous. From a critical point of view, many clinical studies missed their chance because of small cohort size; moreover, methodological standardisation is generally lacking. On the other hand, the very encouraging results achieved so far, together with the comprehensive analyses of a few research groups, foster the prediction that DTC/MRD issues will soon expand the standard TNM classification.

Workshop on Cancer Biometrics: Identifying Biomarkers and Surrogates of Cancer in Patients

The current excitement about molecular targeted therapies has driven much of the recent dialog in cancer diagnosis and treatment. Particularly in the biologic therapy of cancer, identifiable antigenic T-cell targets restricted by MHC molecules and the related novel stress molecules such as MICA/B and Letal allow a degree of precision previously unknown in cancer therapy. We have previously held workshops on immunologic monitoring and angiogenesis monitoring. This workshop was designed to discuss the state of the art in identification of biomarkers and surrogates of tumor in patients with cancer, with particular emphasis on assays within the blood and tumor. We distinguish this from immunologic monitoring in the sense that it is primarily a measure of the tumor burden as opposed to the immune response to it. Recommendations for intensive investigation and targeted funding to enable such strategies were developed in seven areas: genomic analysis; detection of molecular markers in peripheral blood and lymph node by tumor capture and RT-PCR; serum, plasma, and tumor proteomics; immune polymorphisms; high content screening using flow and imaging cytometry; immunohistochemistry and tissue microarrays; and assessment of immune infiltrate and necrosis in tumors. Concrete recommendations for current application and enabling further development in cancer biometrics are summarized. This will allow a more informed, rapid, and accurate assessment of novel cancer therapies.

Detection of circulating tumor cells and of tumor DNA in plasma during tumor progression in rats

The role and clinical significance of circulating tumor cells and of tumor DNA in the plasma have not yet been clarified. In the present study, we compared rates of detection of tumor-derived DNA in the buffy coat to those in plasma from tumor-bearing rats, and we attempted to correlate these rates with the progression of tumors. We injected DHD/K12-PROb cancer cells subcutaneously into BD-IX rats and divided the animals into six groups according to the time between the injection of tumor cells and euthanasia. After euthanasia, macroscopic metastases were assessed and samples of blood and lung were collected. We used mutant allele-specific amplification by PCR to detect tumor-derived DNA. We detected tumor DNA in lung samples from the first week after inoculation, in plasma from the third week and in the buffy coat from the fifth week. All animals analyzed on the 11th week had macro- or micrometastases in their lungs. Regardless of group, the rate of PCR-positive plasma samples was significantly higher than that of circulating tumor cells (P=0.005). In animals with metastases, this difference was also statistically significant (P=0.008). However, neither the detection of tumor DNA in the plasma nor the presence of circulating tumor cells was strongly correlated with the presence of metastases. Thus, cell-free tumor DNA was detected sooner and more frequently than circulating tumor cells and the dissemination of tumor DNA in the plasma seems to be much more common than detectable hematogenic tumor cells during the spread of colorectal cancer.

Carcinoembryonic antigen messenger RNA expression using nested reverse transcription-PCR in the peripheral blood during follow-up period of patients who underwent curative surgery for biliary-pancreatic cancer: longitudinal analyses

PURPOSE

Outcome for patients with biliary-pancreatic cancer is still poor, despite curative operation. We investigated the clinical significance of molecular detection of circulating cancer cells in the blood as an early indicator of relapse during follow-up of patients who underwent a curative operation for biliary-pancreatic cancer.

PATIENTS AND METHODS

We followed 53 patients who underwent a curative operation for biliary-pancreatic cancer between 1996 and 2001. We used reverse transcription-PCR in the peripheral blood to evaluate carcinoembryonic antigen (CEA) mRNA expression for molecular detection of circulating cancer cells. Follow-up examinations every 3 months after surgery included CEA mRNA expression in the blood, serum CEA, serum carbohydrate antigen 19-9 (CA19-9), and computed tomography or magnetic resonance imaging.

RESULTS

Sixteen of 53 patients (30.2%) were diagnosed with a recurrence by imaging studies. The CEA mRNA detection rate in the peripheral blood of these 16 patients was 75% compared with 5.4% in the 37 patients without relapse (P < 0.001). Sensitivity of CEA mRNA, CEA, and CA19-9 serum levels was 75.0%, 50.0%, and 68.8%, respectively. Similarly, specificity was 94.6%, 64.9%, and 81.1%, respectively. CEA mRNA was expressed in the blood, even though tumor markers CEA and CA19-9 were within the normal range in patients with relapse. CEA mRNA expression in the blood, as well as the serum level of CA19-9, tended to be detected a few months earlier than detection by imaging modalities.

CONCLUSIONS

During the follow-up of patients who undergo a curative operation for biliary-pancreatic cancer, CEA mRNA expression in the peripheral blood might be a useful and early indicator of relapse.

Comparison of methylation-specific polymerase chain reaction (MSP) with reverse transcriptase-polymerase chain reaction (RT-PCR) in peripheral blood of gastric cancer patients

BACKGROUND AND OBJECTIVES

To achieve a complete cure in gastric cancer, primary and recurrent tumors must be detected at an early stage. This study was designed to compare carcinoembryonic antigen (CEA)-specific reverse transcriptase-polymerase chain reaction (RT-PCR) and methylation-specific polymerase chain reaction (MSP) for p16, E-cadherin, and retinoic acid receptor beta (RARbeta) genes using blood samples from gastric cancer patients.

METHODS

Preoperative blood samples obtained from 41 patients with gastric cancer, including 9 with early-stage disease, and were subjected to RT-PCR and MSP assays.

RESULTS

Ten of 41 (24%) patients exhibited a CEA-specific signal by RT-PCR. Positive rates were 11, 13, 50, and 50% in stages I, II, III, and IV, respectively. A significant association was found between RT-PCR results and stage (P< 0.01). The MSP assay detected hypermethylation of p16 in 9 patients (22%), E-cadherin in 9 patients (22%), and RARbeta in 6 patients (15%). Altogether, 18 patients (44%) showed hypermethylation. The positive rates were 37, 50, 40, and 75% in stages I, II, III, and IV, respectively. A significant association was found between aberrant methylation and venous invasion (P< 0.05). Neither the CEA-specific signal nor hypermethylation was detected in serum from control volunteers.

CONCLUSIONS

The detection rate of MSP was higher than that of RT-PCR in gastric cancer. Both assays can serve as markers that allow selection of those cases requiring more intensive screening and aggressive postoperative treatment.

Carcinoembryonic antigen mRNA in the mesenteric vein is not a predictor of hepatic metastasis in patients with resectable colorectal cancer: a long-term study

PURPOSE

The clinical value of carcinoembryonic antigen messenger ribonucleic acid in the draining venous blood has been controversial because of short observation period. The authors prospectively investigated the clinical significance of detection of carcinoembryonic antigen messenger ribonucleic acid in the draining venous blood to predict hepatic metastases in patients with resectable colorectal cancer.

METHODS

Drainage venous blood from 80 patients who underwent curative resections for colorectal cancer were obtained immediately before surgery to determine the presence of cancer cells by means of reverse transcription polymerase chain reaction.

RESULTS

After an average follow-up period of 52.1 months, 7 of the 35 patients (20 percent) with positive carcinoembryonic antigen messenger ribonucleic acid had hepatic metastases, whereas 2 of the 45 patients (4.5 percent) with negative carcinoembryonic antigen messenger ribonucleic acid had hepatic metastases. The cumulative probability of hepatic metastatic recurrence rate differed significantly between two patient groups with positive or negative carcinoembryonic antigen messenger ribonucleic acid expression in the drainage vein (log-rank, 4.900; P = 0.0269). However, 28 of the 35 patients (80 percent) with positive carcinoembryonic antigen messenger ribonucleic acid did not have hepatic metastases. Additionally, Cox proportional hazards models identified the presence of lymph node metastases as the only independent predictor of hepatic metastatic recurrence.

CONCLUSIONS

This study failed to demonstrate the high predictive value of carcinoembryonic antigen messenger ribonucleic acid detection in the draining venous blood for the development of hepatic metastases. However, the authors demonstrated that the presence of cancer cells in the draining venous blood was the essential and initial step to the development of hepatic metastasis.

Detection of disseminated tumour cells in blood and bone marrow samples of patients undergoing hepatic resection for metastasis of colorectal cancer

BACKGROUND

In 50-60 per cent of patients who undergo hepatic resection for metastasis of colorectal cancer the first site of tumour recurrence is extrahepatic, indicating the presence of more extensive disease at the time of resection. The aim of this study was to evaluate whether the presence of disseminated tumour cells in blood and bone marrow could predict extrahepatic tumour recurrence.

METHODS

Cytokeratin 20 (CK20) reverse transcriptase-polymerase chain reaction was used to study the presence of tumour cells in preoperative peripheral blood and bone marrow samples from 41 patients with liver metastasis scheduled for surgical resection.

RESULTS

CK20 expression was detected in six of 41 peripheral blood samples and in eight of 32 bone marrow samples. There was no correlation between CK20-positive samples and subsequent extrahepatic recurrence. Positive blood samples did, however, correlate with high serum carcinoembryonic antigen level and large tumour volume. None of the 14 patients previously treated with chemotherapy had CK20-positive samples, whereas six of 27 blood and eight of 20 bone marrow samples were positive in the chemotherapy-naive group.

CONCLUSION

Although the number of patients in this study is limited, the presence of disseminated tumour cells did not predict subsequent extrahepatic recurrence. The results strongly suggest that the presence of circulating tumour cells in peripheral blood may reflect transient shedding of tumour cells related to large tumour volume.

Relevance of disseminated tumour cells in blood and bone marrow of patients with solid epithelial tumours in perspective

Currently-used systems to predict prognosis in patients with solid epithelial tumours after surgical resection of the tumour do not give any guarantees for the individual patient. In this respect the clinical relevance of the presence of disseminated tumour cells in blood and bone marrow has been frequently studied. Because of growing awareness that information on merely the presence of disseminated tumour cells is not sufficient for prognostic and therapeutic purposes, attention for characterization of disseminated tumour cells has increased. Numerous reviews have already been published on the detection and clinical relevance of disseminated tumour cells. Therefore, this paper will mainly focus on the biological significance of these cells and discusses the (in)efficiency of the metastatic process, the genotypic and phenotypic characteristics of disseminated tumour cells, and their structure of appearance. Despite the fact that information gained on the several individual aspects is substantial, it did not render any solid solutions for individual patient management yet. Hence, a combined approach of several aspects of disseminated tumour cells together with characteristics and behaviour of the primary tumour is needed to substantially improve our knowledge on the role of disseminated tumour cells in the complex process of tumour metastasis.

Prognostic value of postoperative detection of blood circulating tumor cells in patients with colorectal cancer operated on for cure

OBJECTIVE

To assess whether postoperative detection of circulating tumor cells in peripheral blood influenced the prognosis of patients with colorectal cancer after radical surgery.

SUMMARY BACKGROUND DATA

In a previous study, the authors demonstrated that baseline detection of blood circulating tumor cells does not have prognostic significance in patients with colorectal cancer. However, surgical procedures may increase tumor cell detachment and mobilization.

METHODS

Sixty-six patients with histologically confirmed colorectal cancer operated on for cure were included in this study. Circulating tumor cells were detected by means of reverse transcriptase-polymerase chain reaction targeting to carcinoembryonic antigen messenger RNA in peripheral blood samples obtained 24 hours after surgery. Endpoints of the study were tumor recurrence, overall survival, and cancer-related survival. Univariate (Kaplan-Meier method) and multivariate (Cox regression model) analyses were performed.

RESULTS

After a median follow-up of 36 months, 15 patients (23%) had tumor relapse and 14 had died (21%), 8 of them from a cancer-related cause. Cox regression analysis identified lymph node metastases and gender as independent predictors of tumor recurrence and cancer-related survival, whereas overall survival was dependent on the degree of differentiation of the primary tumor. More importantly, the presence of circulating tumor cells after surgery had no prognostic influence on tumor recurrence, overall survival, or cancer-related survival.

CONCLUSIONS

Postoperative detection of blood circulating tumor cells had no prognostic significance in patients with colorectal cancer operated on for cure.

Clinical significance of circulating tumor cells in blood by molecular detection and tumor markers in esophageal cancer

BACKGROUND

The clinical significance of circulating tumor cells in the blood during surgery has not been elucidated in esophageal squamous cell carcinoma (ESCC). We evaluated the relationship between circulating tumor cells and clinicopathologic findings, compared with that of serum squamous cell carcinoma (SCC) antigen and carcinoembryonic antigen (CEA), in ESCC.

METHODS

Blood samples from 54 consecutive patients were obtained from the peripheral artery and the superior vena cava at three points in time: immediately before surgery, and before and after tumor resection. CEA-specific reverse transcriptase-polymerase chain reaction (RT-PCR), which can quantify circulating tumor cells in blood, was performed. The preoperative values of serum SCC antigen and CEA were also obtained for all patients.

RESULTS

CEA messenger RNA (CEA mRNA) was detected in the blood of 31 out of 54 patients (57.4%). CEA mRNA positivity was detected most frequently after tumor resection and correlated with nodal status and stage grouping. The incidence of total recurrence and blood-borne recurrence was significantly greater in patients with CEA mRNA positivity than in those with CEA mRNA negativity (P =.036 and.0026, respectively). Preoperative serum levels of SCC antigen and CEA did not correlate with clinicopathologic findings and tumor recurrence.

CONCLUSIONS

CEA mRNA detected by RT-PCR was more predictive of tumor recurrence than serum tumor markers. Effective adjuvant therapy is recommended for patients with CEA mRNA positive expression.

Reliability of quantitative reverse-transcriptase-PCR-based detection of tumour cells in the blood between different laboratories using a standardised protocol

Differences in methods of reverse-transcriptase (RT)-polymerase chain reaction (PCR)-based detection of tumour cells in the blood gives rise to conflicting results, and standardisation is urgently needed. This pilot study aimed to assess the variation of RT-PCR-based detection of tumour cells in blood between four different laboratories using a commercially available kit with a standardised protocol. This kit allows comparison of results from different laboratories and facilitates the investigation of the influence of pre-analytical parameters. All laboratories analysed identical sets of blood samples spiked with tumour cells in a concentration range of 1-100 tumour cells/ml. To study at which level variation was introduced, three kinds of sample sets were generated in which (i) tumour cell RNA was spiked in the RNA of mononuclear cells (MNC), (ii) tumour cells were spiked in isolated MNC, and (iii) tumour cells were spiked in blood. Real-time quantitative RT-PCR was used to detect and quantify cytokeratin 20 (CK20) expression, which is indicative for the presence of epithelial tumour cells. All laboratories were able to detect CK20 expression in all spiked-RNA samples with limited variation in expression levels between laboratories. There was a positive correlation between the amount of spiked tumour cell RNA and CK20 expression level. RT-PCR analysis of spiked-MNC samples resulted in more variation in the CK20 expression levels between laboratories, however again all spiked samples were reported to be positive by all of the laboratories. The evaluation of spiked-blood samples gave rise to considerable quantitative and qualitative variation between the laboratories. Our results underline the importance and need for standardisation and extended quality control studies in the field of pre-analytics.

Quantitative detection of CEA expressing free tumor cells in the peripheral blood of colorectal cancer patients during surgery with real-time RT-PCR on a LightCycler

We applied novel real-time reverse transcriptase-polymerase chain reaction (RT-PCR) with a LightCycler for quantitative detection of carcinoembryonic antigen (CEA) mRNA expressing tumor cells in the peripheral blood of colorectal cancer patients. Analysis of peripheral blood samples from 99 potentially curative colorectal cancer patients revealed a significantly higher mean CEA mRNA value in post-operative bloods (18.71) than in pre-operative blood (1.03) (P=0.003). Kaplan-Meier analysis demonstrated disease free survival of patients with positive CEA mRNA in post-operative blood to be significantly shorter than in cases negative for CEA mRNA (P=0.03). These results suggest that tumor cells could be shed into the bloodstream during surgical procedures, and these free tumor cells are accompanied by a poor patient outcome. Real-time quantitative RT-PCR is a useful technique for quantitative assessment of free tumor cells in the peripheral blood of colorectal cancer patients.

Hematogenous dissemination of lung cancer cells during surgery: quantitative detection by flow cytometry and prognostic significance

Shedding of neoplastic cells into the circulation is an essential event for the hematogenous metastasis of solid tumors. Recently, several studies reported that a high frequency of cancer cells could be detected in the bloodstream during surgery. The intraoperative detection of hematogenous dissemination of cancer cells was able to identify a subset of patients with malignant diseases at high risk for postoperative metastasis and to predict a poor prognosis. In order to evaluate the association between intraoperative dissemination of cancer cells and postsurgical survival of patients with non-small cell lung cancer (NSCLC), we developed a flow cytometric assay for specific detection of lung cancer cells in the blood. The monocyte-enriched population in the blood was separated by a modified Ficoll-Hypaque density centrifugation and then labeled with a combination of monoclonal antibodies specific for CD45, cytokeratin (CK) and two antigens expressed on lung cancer cells (2F7 and S5A). The assay could detect quantitatively lung cancer cells (defined as CD45(-1) CK(+) 2F7/S5A(+) cells), with the sensitivity limit of one cancer cell in 10(5) normal leukocytes. The specificity for lung cancer was 97%, which was calculated from the results of healthy subjects (20 cases) and patients affected with benign pulmonary diseases (26 cases) or esophageal cancer (14 cases). Blood samples of 31 NSCLC patients were collected from pulmonary vein during open thoracic surgery. Fifteen of them (48.4%) were found to have positive test results. The average cancer cell counts in these cases were 0.306 x 10(6)/l. Patients under 55 years of age had a significantly higher percentage of positive findings than those over 55 years of age (P < 0.05). The positive rate increased over the stages and lymph node status, but the differences were not statistically significant. Moreover, patients with squamous cell carcinoma at later stages (stages III and IV) had an increased frequency of positive test results than those at earlier stages (stages I and II, P < 0.05). In contrast, no such a difference was found in cases with adenocarcinoma. On the basis of 30-months follow-up date, the median survival time and 2-year survival rate for patients with positive and negative findings were 11 vs. 27 months, and 26.7 vs. 62.5%, respectively. There was a statistically significant difference between overall survival curves that favored the patients with negative test results (P = 0.023). Multivariate analysis indicated the stage of disease and the positive test results as two independent factors that affected survival time (P = 0.017 and 0.027). When a comparison was made within the patients at stages III and IV, the presence of cancer cells in blood was associated with a significantly shorter survival. These data indicate that the hematogenous dissemination of lung cancer cells during surgery would be one of the mechanisms of postoperative tumor metastasis. The detection of these cells may help to identify patients with poor prognosis.

A novel method for monitoring response to chemotherapy based on the detection of circulating cancer cells: a case report

We describe a novel method for detecting micrometastasis in the blood stream of cancer patients based on RT-PCR amplification of tumor-associated carcinoembryonic antigen (CEA) mRNA. To increase sensitivity and specificity of RT-PCR, CEA transcript was selectively up-regulated in cancer cells by exposure of peripheral blood to non-toxic concentrations of staurosporine (ST). Thereafter, polyA(+) RNA was extracted from tumor cells captured by means of magnetic beads coated with a monoclonal antibody against a common human epithelial antigen. Finally, RNA was subjected to RT-PCR analysis of CEA transcript. Using this approach, we demonstrated an ST-mediated increase in CEA transcript in blood specimens collected from a patient with metastatic colon cancer before receiving treatment with 5-fluorouracil/leucovorin. After a few cycles of chemotherapy, CEA-positive tumor cells were no longer detected. Clinical follow-up of this patient indicated that treatment with chemotherapy induced a dramatic reduction in liver metastasis. Therefore, it can be hypothesized that lack of CEA transcript detection might be consistent with disappearance or at least marked reduction of circulating tumor cells.

Detection of beta-subunit human chorionic gonadotropin mRNA in the peripheral blood of patients with nonmetastatic gestational trophoblastic disease

OBJECTIVE

The aim of this study was to detect beta-subunit human chorionic gonadotropin (beta(h)CG) mRNA in the peripheral blood samples of patients with nonmetastatic gestational trophoblastic disease (GTD) undergoing hysterectomy.

METHODS

Heparinized peripheral blood samples were obtained from four patients with nonmetastatic GTD before, during, and after hysterectomy. The beta(h)CG mRNA expression was examined by reverse transcriptase-polymerase chain reaction using beta(h)CG primers. The expression of beta(h)CG mRNA was quantified using a densitometer.

RESULTS

Beta(h)CG expression was detected in all patients before and during hysterectomy. The expression of beta(h)CG mRNA during operation was so high that it could not be quantified using densitometer. The expression decreased rapidly after operation.

CONCLUSIONS

Disseminated trophoblastic cells are present in the peripheral blood even in cases without metastasis. Trophoblastic cells circulating in the peripheral blood can be reduced by surgical intervention.

Detection and clinical significance of occult tumour cells in colorectal cancer

BACKGROUND

A variety of techniques have been employed for the detection of occult tumour cells in the blood, bone marrow and lymph nodes of patients with colorectal cancer. This review examines the methods used, results obtained and the clinical significance of studies in this field.

METHODS

A Medline literature search was performed using the terms colorectal cancer, minimal residual disease, micrometastasis, polymerase chain reaction, reverse transcriptase polymerase chain reaction and immunocytochemistry; further references were obtained from key articles.

RESULTS

Immunocytochemical examination of bone marrow is the benchmark for detecting clinically significant occult disease. Larger standardized studies are required to confirm the prognostic significance of molecular assays for the detection of tumour cells in blood and bone marrow. The prognostic significance of lymph node tumour cells detected by either immunohistochemical or molecular methods awaits further affirmation.

CONCLUSION

Standardization of terminology and techniques used, combined with large prospective clinical studies, is required if detection of occult residual disease is to become a prognostic marker for recurrence in colorectal cancer.

Colorectal cancer surveillance post-surgery

Current surveillance methods for detecting recurrence after apparently curative colorectal cancer resection are insensitive and have not been shown to significantly improve survival. New surveillance methods based on molecular, flow cytometric and immunohistochemical detection of small numbers of tumour cells may prove more sensitive in detecting early recurrent cancer and may improve outcome.

Minimal residual disease in gastrointestinal cancer

Tumor progression after curative resection of gastrointestinal carcinomas is probably caused by pre- or intraoperative tumor cell dissemination. Disseminated tumor cells are generally detected by immunohistochemistry- or PCR-based molecular-biology methods. A consensus on which is the most adequate detection method has not yet been found, which makes the comparison of data difficult. The prognostic relevance of disseminated cells has been shown, at least in part, for esophageal, gastric, pancreatic, and colonic cancer. The data regarding hepatocellular cancer is conflicting. This article gives a critical review of tumor cell detection in gastrointestinal cancer.