Prognostic value and clinical implications of disseminated cancer cells in the peritoneal cavity detected by reverse transcriptase-polymerase chain reaction and cytology

Prognostic value of molecular cytology by one-step nucleic acid amplification (OSNA) assay of peritoneal washings in advanced gastric cancer patients

Peritoneal dissemination is a common form of gastric cancer (GC) recurrence, despite surgery with curative intent. This study aimed to evaluate the prognostic value of intraperitoneal lavage One-Step Nucleic Acid Amplification (OSNA) assay in advanced GC patients. OSNA assay targeting CK-19 mRNA was applied to detect free cancer cells (FCC) in intraperitoneal lavage samples obtained during gastrectomy. A total of 82 GC patients were enrolled to investigate the correlation between OSNA assay and patient's prognosis. Of the 82 patients, OSNA assay was positive in 25 (30.5%) patients. The median OS in OSNA positive patients was significantly lower than in OSNA negative patients (19 vs 45 months). Positive OSNA assay result was a significant unfavourable prognostic factor in both, univariable (HR 3.45, 95% CI 0.95-12.48; p = 0.0030) and multivariable analysis (HR 3.10, 95% CI 1.22-8.54; p = 0.0298). Positive OSNA assay in intraperitoneal lavage is a valuable indicator of poor survival in advanced GC patients after multimodal treatment. After further confirmation on larger sample size, OSNA assay of peritoneal washings could be considered an adjunct tool to conventional cytology, the current gold standard, to provide precise intraoperative staging and additional prognostic information.

Transcriptomic Profiling Identifies a Risk Stratification Signature for Predicting Peritoneal Recurrence and Micrometastasis in Gastric Cancer

PURPOSE

Gastric cancer peritoneal carcinomatosis is fatal. Delay in detection of peritoneal metastases contributes to high mortality, highlighting the need to develop biomarkers that can help identify patients at high risk for peritoneal recurrence or metastasis.

EXPERIMENTAL DESIGN

We performed a systematic discovery and validation for the identification of peritoneal recurrence prediction and peritoneal metastasis detection biomarkers by analyzing expression profiling datasets from 249 patients with gastric cancer, followed by analysis of 426 patients from three cohorts for clinical validation.

RESULTS

Genome-wide expression profiling identified a 12-gene panel for robust prediction of peritoneal recurrence in patients with gastric cancer (AUC = 0.95), which was successfully validated in a second dataset (AUC = 0.86). Examination of 216 specimens from a training cohort allowed us to establish a six gene-based risk-prediction model [AUC = 0.72; 95% confidence interval (CI): 0.66-0.78], which was subsequently validated in an independent cohort of 111 patients with gastric cancer (AUC = 0.76; 95% CI: 0.67-0.83). In both cohorts, combining tumor morphology and depth of invasion further improved the predictive accuracy of the prediction model (AUC = 0.84). Thereafter, we evaluated the performance of the identical six-gene panel for its ability to detect peritoneal metastasis by analyzing 210 gastric cancer specimens (prior 111 patients plus additional 99 cases), which discriminated patients with and without peritoneal metastasis (AUC = 0.72). Finally, our biomarker panel was also remarkably effective for identifying peritoneal micrometastasis (AUC = 0.72), and its diagnostic accuracy was significantly enhanced when depth of invasion was included in the model (AUC = 0.85).

CONCLUSIONS

Our novel transcriptomic signature for risk stratification and identification of high-risk patients with peritoneal carcinomatosis might serve as an important clinical decision making in patients with gastric cancer.

Predicting Peritoneal Dissemination of Gastric Cancer in the Era of Precision Medicine: Molecular Characterization and Biomarkers

Gastric cancer (GC) is a leading cause of worldwide cancer-related death. Being a highly heterogeneous disease, the current treatment of GC has been suboptimal due to the lack of subtype-dependent therapies. Peritoneal dissemination (PD) is a common pattern of GC metastasis associated with poor prognosis. Therefore, it is urgently necessary to identify patients at high risk of PD. PD is found to be associated with Lauren diffuse type GC. Molecular profiling of GC, especially diffuse type GC, has been utilized to identify molecular alterations and has given rise to various molecular classifications, shedding light on the underlying mechanism of PD and enabling identification of patients at higher PD risk. In addition, a series of diagnositc and prognostic biomarkers of PD from serum, peritoneal lavages and primary GCs have been reported. This comprehensive review summarizes findings on the multi-omic characteristics of diffuse type GC, the clinical significance of updating molecular classifications of GC in association with PD risk and research advances in PD-associated biomarkers.

Diagnostic value of negative enrichment and immune fluorescence in situ hybridization for intraperitoneal free cancer cells of gastric cancer

Objective

To explore the intraperitoneal free cancer cell (IFCC) detection value of negative enrichment and immune fluorescence in situ hybridization (NEimFISH) on chromosomes (CEN) 8/17.

Methods

To verify the reliability of NEimFISH, 29 gastric cancer tumors, their adjacent tissues and greater omental tissues were tested. Our study then included 105 gastric cancer patients for IFCC. We defined patients as IFCC-positive if a signal was detected, regardless of the detailed cancer cell numbers. A comparison of clinicopathological features was conducted among IFCC groups. We also compared the diagnosis value and peritoneal recurrence predictive value among different detection methods. The comparison of IFCC number was also conducted among different groups.

Results

A cutoff of 2.5 positive cells could distinguish all benign tissue samples and 97% of malignant tissue samples in our study. Compared to intestinal gastric cancer, patients with diffuse gastric cancer tended to have more IFCCs (6 vs. 4, P=0.002). The IFCC counts were often higher in the lymphovascular invasion positive group than negative group (3 vs. 1, P=0.022). All IFCC samples that were considered positive using conventional cytology were also found to be positive using NEimFISH. When compared to conventional cytology and paraffin pathology, NEimFISH had a higher IFCC positive rate (68.9%) and higher one-year peritoneal recurrence predictive value with area under the curve (AUC) of 0.922.

Conclusions

Gastric cancer could be effectively diagnosed by NEimFISH. The IFCC number found using NEimFISH on CEN8/17 is closely associated with Lauren type and vascular invasion of cancer. NEimFISH is a reliable detection modality with a higher positive detection rate, higher one-year peritoneal recurrence predictive value and quantitative features for IFCC of gastric cancer.

Subclinical cancer cell dissemination in peritoneal lavage fluid detected by reverse-transcription polymerase chain reaction identifies patients at high risk for peritoneal recurrence and consequent impaired survival in the setting of preoperative chemoradiation therapy for pancreatic cancer

BACKGROUND

Preoperative chemoradiation therapy is a promising strategy for pancreatic cancer. Peritoneal recurrence is a major recurrence pattern after surgery for pancreatic cancer following preoperative chemoradiation therapy, even in patients with negative peritoneal lavage fluid cytology. Previous reports have indicated that the detection of carcinoembryonic antigen mRNA by reverse transcription polymerase chain reaction is useful for evaluating subclinical tumor cell dissemination in peritoneal lavage fluid.

METHODS

Patients with resectable and borderline resectable pancreatic cancer treated with preoperative gemcitabine-based chemoradiation therapy and subsequent surgery were enrolled in this study. In all patients, a conventional cytologic examination of peritoneal lavage fluid from laparotomy confirmed the negative peritoneal cytology status. Carcinoembryonic antigen mRNA was detected in the peritoneal lavage fluid at laparotomy using reverse transcription polymerase chain reaction. Recurrence patterns and survival were evaluated in association with the carcinoembryonic antigen mRNA status in the peritoneal lavage fluid.

RESULTS

The peritoneal lavage fluid from 57 of the 237 patients (24%) was carcinoembryonic antigen mRNA(+). The carcinoembryonic antigen mRNA(+) patients had a significantly higher incidence of peritoneal recurrence than the carcinoembryonic antigen mRNA(-) patients (36% vs. 15%, P < .001). The 5-year survival rates of the carcinoembryonic antigen mRNA(+) and carcinoembryonic antigen mRNA(-) patients were 31% and 51%, respectively (P = .037). A multivariable analysis for survival revealed that borderline resectability, positive nodal status, and positive carcinoembryonic antigen mRNA status were independent variables for impaired survival.

CONCLUSION

Carcinoembryonic antigen mRNA(+) status was associated with a significantly increased incidence of peritoneal recurrence in patients with pancreatic cancer treated with preoperative chemoradiation therapy, resulting in impaired survival.

The Detection of Messenger RNA for Carcinoembryonic Antigen and Cytokeratin 20 in Peritoneal Washing Fluid in Patients with Advanced Gastric Cancer

Background/Aims

Peritoneal micrometastasis is known to play an important role in the recurrence of gastric cancer. However, its effects remain equivocal. Herein, we examine the messenger RNA (mRNA) as tumor markers, carcinoembryonic antigen (CEA), and cytokeratin 20 (CK20), in peritoneal washing fluid. Moreover, we evaluate whether these results could predict the recurrence of gastric cancer following curative resection.

Methods

We prospectively enrolled 132 patients with gastric cancers, who had received an operation, between January 2010 and January 2013. The peritoneal lavage fluid was collected at the operation field and semi-quantitative PCR was performed using the primers for CEA and CK20. We excluded patients with stage IA (n=28) early gastric cancer, positive cytologic examination of peritoneal washings (n=7), and those who were lost during follow up (n=18).

Results

A total of 79 patients with gastric cancers were enrolled, and the mean follow-up period was 39.95±19.25 months (range, 5-72 months). According to the multivariate analysis, T4 stage at the initial diagnosis was significantly associated with recurrence. All cases of recurrence were CEA positive and 6 cases were CK20 positive. The positive and negative predictive values of CEA were 32.0% and 100%, respectively, whereas those of CK20 were 37.5% and 71.4%, respectively. Disease free survival of CK20-negative cases was 36.17±20.28 months and that of CK20-positive cases was 32.06±22.95 months (p=0.39).

Conclusions

It is unlikely that the real time polymerase chain reaction results of mRNA for CEA and CK20 in peritoneal washing fluid can predict recurrence. However, negative results can convince surgeons to perform curative R0 resection.

Prognostic significance, diagnosis and treatment in patients with gastric cancer and positive peritoneal washings. A review of the literature

Peritoneal dissemination is a common consequence of a relapse following a radical surgical treatment of gastric cancer. The development of the disease in the peritoneum depends not only on its stage, but also on free cancer cells exfoliated from the tumor mass or from involved lymph nodes, and which are capable of being implanted in the peritoneum. According to the latest TNM (7 edition; 2010) classification, patients with free cancer cells in the peritoneal washings qualify for stage IV of the disease. Patients in whom free cancer cells were found during the operation - have a recurrence of gastric cancer - mainly in the peritoneum, and the majority of them die within two years of the diagnosis. To properly assess the prognosis, it is vital to determine the stage of cancer by additionally assessing the washings for the presence of free cancer cells before taking a therapeutic decision. This also allows identifying those patients who require different medical procedures to obtain the best treatment results possible. Medical literature describes various methods of examining peritoneal washings aimed at detecting free cancer cells. The methods apply different cancer cell detection rates, sensitivity and specificity in prediction of a peritoneal relapse. Oncological Departments performing the evaluation of the washings employ non-standard methods of treatment in this group of patients and the results presented are promising.

Detection value of free cancer cells in peritoneal washing in gastric cancer: a systematic review and meta-analysis

Intraperitoneal free cancer cells in gastric adenocarcinoma are associated with a poor outcome. However, the true prognostic value of intraperitoneal free cancer cells is still unclear, leading to a lack of consensus in the management of gastric cancer. The aim of the present study is to perform a systematic review and meta-analysis to analyze intraperitoneal free cancer cells-positive patients with regard to tumor oncologic stage, recurrence, grade of cellular differentiation, and survival rates and to analyze the clinical significance of intraperitoneal free cancer cells with regard to prognosis. Databases were searched up to January 2016 for prognostic factors associated with intraperitoneal free cancer cells, including oncologic stage, depth of neoplasm invasion, lymph nodal spread, differentiation grade of the tumor, and recurrence and survival rates. A total of 100 studies were identified. Meta-analysis revealed a clear association between intraperitoneal free cancer cells and a poor prognosis. intraperitoneal free cancer cells -positive patients had higher rates of nodal spread (risk difference: 0.29; p<0.01), serosal invasion (risk difference: 0.43; p<0.01), recurrence (after 60 months of follow-up, risk difference: 0.44; p<0.01), and mortality (after 60 months of follow-up, risk difference: 0.34; p<0.01). Intraperitoneal free cancer cells are associated with a poor outcome in gastric cancer. This surrogate biomarker should be used to guide therapy both prior to and after surgery.

Prognostic value of occult tumor cells obtained by peritoneal lavage in patients with resectable pancreatic cancer and no ascites: A systematic review

The poor survival of patients with resectable pancreatic cancer might be related to the presence of occult peritoneal tumor cells (OPTC). This systematic review studies the prognostic value of cytology and carcinoembryonic antigen (CEA) by real-time polymerase chain reaction in peritoneal fluid. The results suggest that presence of OPTC is related to a worse survival in patients with resectable pancreatic cancer. Future studies should investigate its possible role in selecting patients for specific treatment strategies. J. Surg. Oncol. 2016;114:743-751. © 2016 Wiley Periodicals, Inc.

Recent insights in the therapeutic management of patients with gastric cancer

Gastric cancer remains frequent and one of the most lethal malignancies worldwide. In this article, we aimed to comprehensively review recent insights in the therapeutic management of gastric cancer, with focus on the surgical and perioperative management of resectable forms, and the latest advances regarding advanced diseases. Surgical improvements comprise the use of laparoscopic surgery including staging laparoscopy, a better definition of nodal dissection, and the development of hyperthermic intraperitoneal chemotherapy. The best individualized perioperative management should be assessed before curative-intent surgery for all patients and can consists in perioperative chemotherapy, adjuvant chemo-radiation therapy or adjuvant chemotherapy alone. The optimal timing and sequence of chemotherapy and radiation therapy with respect to surgery should be further explored. Patients with advanced gastric cancer have a poor prognosis. Nevertheless, they can benefit from doublet or triplet chemotherapy combination, including trastuzumab in HER2-positive patients. Upon progression, second-line therapy can be considered in patients with good performance status. Although anti-HER2 (trastuzumab) and anti-VEGFR (ramucirumab) may yield survival benefit, anti-EGFR and anti-HGFR therapies have failed to improve outcomes. Nevertheless, combination regimens containing cytotoxic drugs and targeted therapies should be further evaluated; keeping in mind that gastric cancer biology is different between Asia and the Western countries.

Effect of intraperitoneal chemotherapy and peritoneal lavage in positive peritoneal cytology in gastric cancer. Systematic review and meta-analysis

INTRODUCTION

The most common cause of tumour progression in advanced gastric cancer is peritoneal carcinosis (PC). The necessity to increase the survival in advanced diseases suggested to deliver the chemotherapy directly in the peritoneal cavity also in Cy+/PC- and to experiment the effect of massive peritoneal lavage to wash out the tumour cells. The aim of this study is to investigate the gain in term of survival and peritoneal recurrence rate of the intraperitoneal chemotherapy and/or peritoneal lavage in patients with Cy+/PC-.

MATERIAL AND METHODS

A systematic review with meta-analysis of trials about the effect of intraperitoneal chemotherapy (IPC) and/or peritoneal lavage (PL) on positive cytology in gastric cancer without carcinosis.

RESULTS

Three trials have been included (164 patients: 76 received surgery alone, 51 surgery + IPC and 37 surgery + IPC + PL). Two- and five-years survival is increased by IPC (RR = 1.62, RR = 3.10). 2 and 5 years survival is further increased by IPC + PL (RR = 2.33, RR = 6.19). Peritoneal recurrence is reduced by IPC (OR = 0.45) and by IPC + PL (OR = 0.13).

CONCLUSIONS

Two- and five-years overall survival in patients with free cancer cells without carcinosis is incremented by intraperitoneal chemotherapy. Peritoneal lavage further increases these survival rates and also it further decreases the peritoneal recurrence rate.

Prognostic Significance of Molecular Analysis of Peritoneal Fluid for Patients with Gastric Cancer: A Meta-Analysis

Background

Accurately distinguishing serosal invasion in patients with gastric cancer (GC) prior to surgery can be difficult. Molecular analysis of peritoneal fluid (MAPF) for free cancer cells with higher sensitivity than other methods; however, its prognostic value for GC remains controversial, precluding its application in clinical practice.

Methods

PubMed, EMBASE and other databases were systematically searched. Thirty-one studies were eligible for the meta-analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were pooled for overall survival (OS), disease-free survival (DFS) and peritoneal recurrence-free survival (PRF).

Results

The current meta-analysis focused on patients with GC and negative cytological diagnoses. The results showed that positive MAPF status (MAPF⁺) led to poorer prognoses for OS (HR 2.59, 95% CI 1.99–3.37), DFS (HR 4.92, 95% CI 3.28–7.37) and PRF (HR 2.81, 95% CI 2.12–3.72) compared with negative MAPF status (MAPF^-). Moreover, among the patients with GC who received curative treatment, the MAPF⁺ patients had poorer prognoses for OS (HR 3.27, 95% CI 2.49–4.29), DFS (HR 3.90, 95% CI 2.74–5.57) and PRF (HR 5.45, 95% CI 3.70–8.03). A meta-analysis of multivariate-adjusted HRs demonstrated that MAPF⁺ status was an independent prognostic factor for patients with GC who underwent curative treatment (OS: HR 2.19, 95% CI 1.47–3.28; PRF: HR 3.44, 95% CI 2.01–5.87). Using the identical target genes (CEA, CEA/CK20) as molecular markers, the patients with GC who were MAPF⁺ had significantly worse prognoses for OS (CEA: HR 3.03, 95% CI 2.29–4.01; CEA/CK20: HR 4.24, 95% CI 2.42–7.40), DFS (CEA: HR 3.99, 95% CI 2.24–7.12; CEA/CK20: HR 4.31, 95% CI 1.49–2.48) and PRF (CEA: HR 4.45, 95% CI 2.72–7.31; CEA/CK20: HR 6.46, 95% CI 3.62–11.55) than the patients who were MAPF^-.

Conclusion/Significance

The above results demonstrate that MAPF could be a prognostic indicator for patients with GC who have a negative cytological diagnosis and/or are receiving curative treatment. MAPF could provide clinicians with additional prognostic information that could aid in developing individualized treatment plans prior to surgery. The widely used target genes CEA, CEA/CK20 were confirmed to be valuable MAPF markers for predicting the prognosis of GC.

Free intraperitoneal tumor cells and outcome in gastric cancer patients: a systematic review and meta-analysis

PURPOSE

Despite continuously improving therapies, gastric cancer still shows poor survival in locally advanced stages with local recurrence rates of up to 50% and peritoneal recurrence rates of 17% after curative surgery. We performed a systematic review with meta-analyses to clarify whether positive intraperitoneal cytology (IPC) indicates a high risk of disease recurrence and poor overall survival in gastric cancer.

METHODS

Multiple databases were searched in December 2014 to identify studies on the prognostic significance of positive intraperitoneal cytology in gastric cancer, including: Medline, Biosis, Science Citation Index, Embase, CCMed and publisher databases. Hazard ratios (HR) and associated 95% confidence intervals (CI) were extracted from the identified studies. A meta-analysis was performed using a random-effects model on overall survival, disease-free survival and peritoneal recurrence free survival.

RESULTS

A total of 64 studies with a cumulative sample size of 12,883 patients were included. Cytology, quantitative real time polymerase chain reaction (PCR) or both were performed in 35; 21 and 8 studies, respectively. Meta analyses revealed free intraperitoneal tumor cells (FITC) to be associated with poor overall survival in univariate (HR 3.27; 95% CI 2.82 - 3.78]) and multivariate (HR 2.45; 95% CI 2.04 - 2.94) analysis and poor peritoneal recurrence free survival in univariate (4.15; 95% CI 3.10 - 5.57) and multivariate (3.09; 95% CI 2.02 - 4.71) analysis. Subgroup analysis showed this effect to be independent of the detection method, Western or Asian origin or the time of publication.

CONCLUSIONS

FITC oder positive peritoneal cytology is associated with poor survival and increased peritoneal recurrence in gastric cancer.

Clinical importance of a transcription reverse-transcription concerted (TRC) diagnosis using peritoneal lavage fluids obtained pre- and post-lymphadenectomy from gastric cancer patients

PURPOSE

Our previous study demonstrated that a transcription reverse-transcription concerted (TRC) diagnosis using peritoneal lavage fluids at laparotomy was a potential prognostic factor for gastric cancer patients; however, the clinical importance of a TRC diagnosis from peritoneal lavage fluids after lymphadenectomy remains unclear.

METHODS

TRC amplification targeting CEA mRNA was utilized to detect free cancer cells before and after lymphadenectomy during gastric cancer resection. Of 120 patients who underwent curative gastrectomy for cT2-T4 gastric cancer, 38 whose peritoneal lavage samples were collected pre- and post-lymphadenectomy were eligible for analysis.

RESULTS

Six (16.0 %) patients had CEA positivity before lymphadenectomy (pre-CEA), whereas nine (23.7 %) had CEA positivity after lymphadenectomy (post-CEA). Post-CEA was significantly correlated with higher pathological N-stage. Moreover, the positive post-CEA group had significantly worse relapse-free survival than the negative post-CEA group (p = 0.001). Cox multivariate analysis revealed that post-CEA positivity was a significant predictor of poor relapse-free survival (p = 0.012). It was also a predictor of distant metastasis, but not specific for peritoneal recurrence.

CONCLUSIONS

These findings demonstrated that post-CEA positivity in a TRC diagnosis was a potential predictor of disease recurrence, but not a specific predictor of peritoneal recurrence.

Prognostic value of CEA and CK20 mRNA in the peritoneal lavage fluid of patients undergoing curative surgery for gastric cancer

BACKGROUND

Peritoneal recurrence is the most common type of recurrence in gastric cancer. Although cytological examination of peritoneal lavage fluid has been used to predict peritoneal spread, peritoneal recurrences often occur even in patients with negative cytology. Our previous retrospective study suggested that reverse transcriptase-polymerase chain reaction (RT-PCR) using peritoneal lavage fluid may be useful for predicting peritoneal recurrence in patients with negative cytology. This prospective study was conducted to validate the clinical impact of this RT-PCR method.

METHODS

From July 2009 to June 2012, a total of 118 cT2-4 gastric cancer patients underwent surgery. Since 14 patients were ineligible because they had incurable factors, the remaining 104 eligible patients were evaluated for carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20) messenger RNA (mRNA) using RT-PCR. If either CEA or CK20 mRNA was detected by RT-PCR, the patient was defined as PCR-positive as in our previous study. The association between recurrence-free survival (RFS) and background factors was analyzed using Cox proportional hazards models.

RESULTS

Of 104 patients, 16 (15.4 %) were positive for either CEA or CK20. PCR-positive patients had significantly worse RFS than PCR-negative patients (log-rank p = 0.007). Regarding the pattern of recurrence, 4 of 16 (25 %) PCR-positive patients and 2 of 88 (2 %) PCR-negative patients had peritoneal recurrence (p < 0.001), but there were no significant differences in recurrence at other sites. Cox multivariate analysis indicated only PCR-positivity as a significant predictor of poor RFS (p = 0.029).

CONCLUSION

This prospective study demonstrated that CEA and CK20 PCR results could predict peritoneal recurrence after curative surgery.

Prognostic value of genetic detection using CEA and MAGE in peritoneal washes with gastric carcinoma after curative resection: result of a 3-year follow-up

Peritoneal metastasis is the most frequent cause of death in patients with gastric cancer. Reverse transcriptase-polymerase chain reaction (RT-PCR) assay of peritoneal washes has been used to predict peritoneal metastasis of gastric carcinoma. We applied carcinoembryonic antigen (CEA) and melanoma-associated gene (MAGE) RT-PCR for the detection of peritoneal metastasis of gastric carcinoma after curative surgery and evaluated its clinical significance. Peritoneal washes were obtained from 117 patients with gastric carcinoma. MAGE A1-A6 and CEA RT-PCR were performed, and the results were evaluated according to their clinicopathologic characteristics. Three-year follow-up clinical studies were periodically performed, and disease-free survival rates were retrospectively investigated using the medical records. Among 117 peritoneal fluids, 11 cases (9.4%) revealed MAGE expression and 38 cases (32.5%) revealed CEA expression. When focusing on recurrence rates, RT-PCR-positive had much higher recurrence rates than RT-PCR-negative cases (32.5% vs 5.2%, P < 0.01). Univariate analysis revealed that depth of invasion, lymph node metastasis, tumor node metastasis (TNM) stage, Lauren classification, and MAGE and CEA expressions were independent prognostic factors for recurrence. In a multivariate analysis, MAGE expression and TNM stage were significantly and independently related to recurrence in patients who underwent curative resection. MAGE expression was determined to be the most important prognostic factor for recurrence (hazard ratio: 12.487, P < 0.01). It is feasible to identify free cancer cells in peritoneal lavage by using a MAGE A1-A6 and CEA RT-PCR. MAGE RT-PCR results disclosed significant associations with peritoneal recurrence and proved to be the most important factor for the recurrence rate in patients with gastric carcinoma who had undergone radical resection.

Diagnostic laparoscopy with 5-aminolevulinic-acid-mediated photodynamic diagnosis enhances the detection of peritoneal micrometastases in advanced gastric cancer

OBJECTS

Recently, we reported that diagnostic laparoscopy with photodynamic diagnosis using oral 5-aminolevulinic acid (ALA-PDD) is a promising tool for diagnosing early peritoneal metastases in gastric cancer. The present study evaluated the usefulness of adding ALA-PDD to conventional diagnostic laparoscopy and assessed the association of the ALA-PDD results with peritoneal fluid cytology and molecular diagnostic testing.

METHODS

Diagnostic laparoscopy using sequential white light (WL) and ALA-PDD observations was performed in 52 advanced gastric cancer patients, and the sensitivity of ALA-PDD for detecting peritoneal disease was compared to WL. Peritoneal fluid samples from the same patients were also subjected to cytological examination and molecular diagnosis using a transcription-reverse transcription concerted reaction (TRC).

RESULTS

Twenty-four of the 52 patients (46%) had no macroscopic evidence of peritoneal metastases on WL examination; however, ALA-PDD detected dissemination in 5 of these 24 patients (21%) (pd-P). Cytological examination was negative in 4 of the 5 pd-P patients, and molecular testing using TRC was negative in 3 of the 5 pd-P patients.

CONCLUSIONS

This study demonstrated that diagnostic laparoscopy with ALA-PDD improved the sensitivity for the detection of peritoneal metastases. ALA-PDD may be a useful technique for the preoperative staging of advanced gastric cancer and can complement examinations of peritoneal lavage fluids.

Diagnostic values of carcinoembryonic antigen in predicting peritoneal recurrence after curative resection of gastric cancer: a meta-analysis

AIM

A meta-analysis was performed to assess the diagnostic values of carcinoembryonic antigen (CEA) in predicting the peritoneal recurrence after curative resection of gastric cancer.

METHODS

The Medline, Embase, Web of Science, Ovid and Cochrane databases, Google Scholar and Vivisimo engines were searched to identify studies reporting on the accuracy of CEA protein or CEA mRNA in predicting the postoperative peritoneal recurrence of gastric cancer. Publication bias was demonstrated by Funnel plots and Egger test. The sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated and summary receiver operating characteristic curves were generated.

RESULTS

Seven and eight studies fulfilled the inclusion criteria for CEA protein and mRNA determination, including 635 and 849 patients, respectively. The pooled sensitivity, specificity and DOR of CEA protein for predicting the peritoneal recurrence were 0.77 (95 % CI 0.69-0.84), 0.89 (95 % CI 0.86-0.92), 29.71 (95 % CI 10.27-85.92), respectively. Similarly, the values for CEA mRNA were 0.82 (95 % CI 0.75-0.88), 0.82 (95 % CI 0.79-0.85) and 22.97 (95 % CI 10.90-48.41). Meanwhile, the sensitivity and DOR of CEA protein or mRNA were higher than those of cytology, while higher specificity was noted in cytology assay.

CONCLUSION

CEA protein and mRNA levels in peritoneal lavage show a high diagnostic accuracy and may help accurately predict the peritoneal recurrence after curative resection of gastric cancer.

Prognostic significance of IL-17 mRNA expression in peritoneal lavage in gastric cancer patients who underwent curative resection

Peritoneal dissemination is frequently detected in patients with advanced gastric cancer. The peritoneal cavity is a compartment in which an immunologic host-tumor interaction can occur. There are no reports on the relationship between IL-17 expression in peritoneal lavage and prognosis in gastric cancer patients. Therefore, we investigated the expression of IL-17 mRNA in peritoneal lavage from gastric cancer patients and assessed the association of its expression with clinicopathological parameters and prognosis. Peritoneal lavage was obtained from 114 patients with gastric cancer at initial surgery. Seventy-nine patients underwent curative resection. Among these 79 patients, IL-17 mRNA expression was associated with the depth of tumor invasion (p<0.05). Twelve of the 79 patients who underwent curative resection died, and 9 of those 12 developed peritoneal metastasis. Notably, among the 79 patients who underwent curative resection, those with high expression of IL-17 mRNA in peritoneal lavage had significantly prolonged survival when compared to these patients with low expression of IL-17 mRNA in peritoneal lavage (p<0.05) as evidence by the survival curves. In a multivariate analysis, low expression of IL-17 mRNA in peritoneal lavage and tumor size were found to be independent significant predictive factors for prognosis (HR, 7.91; 95% CI, 1.65-38.03) in the patients who underwent curative resection. IL-17 mRNA expression in peritoneal lavage is a reliable prognostic factor for patients undergoing curative resection for gastric cancer. Low IL-17 expression in the peritoneal cavity may correlate with cancer development in the peritoneal cavity in patients with gastric cancer.

A randomized phase III trial exploring the prognostic value of extensive intraoperative peritoneal lavage in addition to standard treatment for resectable advanced gastric cancer: CCOG 1102 study

A randomized controlled trial has started in Japan to evaluate the efficacy of extensive intraoperative peritoneal lavage in the treatment of resectable advanced gastric cancer. Patients with T3 or deeper carcinoma of the stomach are intraoperatively randomized to either extensive intraoperative peritoneal lavage + arm or extensive intraoperative peritoneal lavage- arm. A total of 300 patients will be accrued from 20 institutions. The primary endpoint is disease-free survival, and secondary end-points are overall survival, peritoneal recurrence-free survival and incidence of adverse events.

Prognostic information derived from RT-PCR analysis of peritoneal fluid in gastric cancer patients: results from a prospective multicenter clinical trial

OBJECTIVE

The purpose of this study is to define the clinical significance of the molecular analysis of peritoneal lavage fluid in patients with gastric cancer in a multicenter prospective trial.

METHODS

Quantitative RT-PCR with CEA and CK-20 mRNA as target markers was introduced for peritoneal lavage diagnosis in 141 patients with clinically advanced gastric cancer from 9 different institutes. We then evaluated the prognostic factors in patients and also evaluated predictive markers for peritoneal recurrence in 124 patients without peritoneal metastasis at surgery

RESULTS

Out of the 141 cases, 140 patients were successfully analyzed by RT-PCR of peritoneal lavage fluids. According to multivariate analysis, the combined results of RT-PCR (CEA and CK-20) and CK-20 alone in addition to pathological N (pN)-stage were significantly correlated with overall survival. Multivariate analysis showed that the RT-PCR (CEA and CK-20) and CEA alone in addition to pathological T-stage, pN-stage, and histological grade were significantly correlated with peritoneal recurrence after surgery.

CONCLUSION

This is the first multicenter prospective study to show that RT-PCR analysis of peritoneal lavage fluid with the combination of CEA and CK-20 markers was useful for predicting overall survival and peritoneal recurrence in patients with clinically advanced gastric cancer.

The clinical importance of a transcription reverse-transcription concerted (TRC) diagnosis using peritoneal lavage fluids in gastric cancer with clinical serosal invasion: a prospective, multicenter study

PURPOSE

We have developed a novel molecular method of diagnosis using the technique of transcriptase-reverse transcriptase concerted reaction (TRC) for the detection of cancer micrometastasis. This study prospectively examined the clinical importance of the TRC diagnosis with peritoneal lavage fluids collected from gastric cancer operations at multiple institutes.

METHODS

TRC amplification targeting carcinoembryonic antigen mRNA was applied to detect gastric cancer cells in peritoneal lavage fluids obtained during gastric cancer resections from nine different hospitals. A total of 137 patients with a clinical diagnosis of serosa-invading neoplasms were enrolled to investigate the correlation between the TRC diagnosis and patient prognosis.

RESULTS

Of the 137 patients, 27 (20%) were positive by cytologic examination. In contrast, TRC targeting carcinoembryonic antigen mRNA was positive in 59 of 137 (54%) patients. TRC positivity was associated with a poorer overall survival in all patients and in the 104 patients who underwent a curative operation. TRC positivity also was associated with the peritoneal recurrence-free survival rate in the 104 curative cases. Multivariate analysis showed that TRC positivity and the pathologic N factor were prognostic factors for the overall survival time.

CONCLUSION

Our prospective multicenter study showed that the TRC test using peritoneal lavage fluids could be a potential prognostic factor to predict patient survival and peritoneal recurrence with clinically diagnosed, serosa-invading gastric cancer.

A systematic review of the accuracy and utility of peritoneal cytology in patients with gastric cancer

BACKGROUND

There is lack of uniformity in the utilization of peritoneal cytology in gastric cancer management. The identification of intraperitoneal free cancer cells (IFCCs) is believed to confer poor prognosis. However, while some of these patients are palliated, others may undergo more aggressive therapies. In this review, we aimed to identify and synthesize findings on the use of peritoneal cytology in predicting peritoneal recurrence and overall survival in curative gastric cancer patients.

METHODS

Electronic literature searches were conducted using Medline, EMBASE, and the Cochrane Central Register of Controlled Trials from January 1, 1998 to December 31, 2009. We determined the accuracy, sensitivity, and specificity of peritoneal cytology in predicting peritoneal recurrence based on four techniques-conventional cytology, immunoassay, immunohistochemistry, and reverse transcriptase-polymerase chain reaction. Recurrence rates and overall survival rates for curative patients were determined, based on positivity or negativity for IFCCs.

RESULTS

Twenty-eight articles were included. All four techniques showed wide variations in accuracy, sensitivity, and specificity in predicting peritoneal recurrence. Recurrence rates for patients positive for IFCCs ranged from 11.1 to 100%, while those negative for IFCCs had recurrence rates of 0-51%. Overall survival was significantly reduced for patients with positive IFCCs. Short follow-up periods and possible duplication of results may limit result interpretation.

CONCLUSION

The presence of IFCCs appears to increase the risk of peritoneal recurrence and is associated with worse overall survival in gastric cancer patients. Further incorporation of peritoneal cytology in clinical decision-making in gastric cancer depends on the development of a consistently accurate and rapid IFCC detection method.

βig-h3 supports gastric cancer cell adhesion, migration and proliferation in peritoneal carcinomatosis

βig-h3 is an extracellular matrix protein and its expression is highly induced by transforming growth factor (TGF-β). It has also been suggested to play an important role in the growth and invasion of colon and pancreatic cancers. In the present study, we demonstrated that βig-h3 is expressed in mesothelial cells, especially in patients with advanced gastric cancer. The positive rate of βig-h3 was significantly higher in cases with a more invasive and advanced serous-type, with visible peritoneal metastasis, and in peritoneal lavage cytological examination (PLC) (+) and peritoneal lavage fluid CEA mRNA(+) subgroups (p<0.05). Our study also showed that the expression of βig-h3 gradually increased with increasing TGF-β1 concentrations in vitro in a time-dependant manner. In addition, βig-h3 also induced human gastric carcinoma cell line (SGC-7901) cell adhesion in a dose-dependent manner and significantly increased cell migration and proliferation. The results suggest that βig-h3 expression in peritoneal mesothelial cells in gastric cancer patients is a marker of the biological behavior of gastric cancer and plays an important role in the process of peritoneal carcinomatosis.

Clinicopathological analysis and prognostic significance of peritoneal cytology in Chinese patients with advanced gastric cancer

BACKGROUND

The influence of peritoneal cytology on survival of patients with gastric cancer has not been consistent. This study was to identify risk factors for positive peritoneal cytology and to evaluate the predictive value of positive cytology among Chinese patients with advanced gastric cancer.

METHODS

The study included 139 patients with gastric cancer macroscopically invading the serosa, who underwent gastrectomy and intra-operative peritoneal cytological examination. In these patients, the relationship between cytological positivity and various clinicopathological features was analysed, and survival analysis was performed to identify independent prognostic factors of significance.

RESULTS

Thirty-eight (27.3%) of 139 patients had positive peritoneal cytology. Although tumour size, lymphovascular invasion, depth of tumour invasion, lymph node metastasis and peritoneal metastasis were correlated with positive cytology, multivariate analysis revealed the depth of tumour invasion and peritoneal metastasis as the independent features affecting the cytology. Patients with a positive cytology result were confirmed to have a greater risk for recurrence in the pattern of peritoneal carcinomatosis and a significant inferior prognosis. Multivariate analysis indicated that positive peritoneal cytology was an independent prognostic factor among the curatively resected patients with advanced gastric cancer and was the prognostic factor most predictive of death for these patients (risk ratio = 2.74).

CONCLUSIONS

Positive peritoneal cytology correlated with advanced features of gastric cancer. It is an independent poor prognostic factor, and it may serve as a guide for adjuvant therapeutic options to improve the survival of gastric cancer.

A proposal of a practical and optimal prophylactic strategy for peritoneal recurrence

Peritoneal metastasis, which often arises in patients with advanced gastric cancer, is well known as a miserable and ill-fated disease. Once peritoneal metastasis is formed, it is extremely difficult to defeat. We advocated EIPL (extensive intraoperative peritoneal lavage) as a useful and practical adjuvant surgical technique for those gastric cancer patients who are likely to suffer from peritoneal recurrence. In this paper, we review the effect of EIPL therapy on prevention of peritoneal recurrence on patients with peritoneal free cancer cells without overt peritoneal metastasis (CY+/P−) through the prospective randomized study, and we verified its potential as an optimal and standard prophylactic therapeutic strategy for peritoneal recurrence.

Free peritoneal tumor cells detection in gastric and colorectal cancer patients

BACKGROUND

Free peritoneal tumor cells (FPTC) derive from the detachment of primary cancer and may result in peritoneal carcinomatosis. Since peritoneal lavage cytology has low sensitivity in detecting FPTC, our aim was to estimate the clinical relevance of FPTC detected using an approach based on multiple molecular techniques.

MATERIALS AND METHODS

Samples of peritoneal lavage were collected from 27 gastric and 48 colorectal cancer patients. FPTC recovery and detection from peritoneal washes was performed by cytological examination and immunomagnetic enrichment for epithelial cells followed by immunofluorescence analysis for epithelial marker EpCAM/CD326 and carcinoembryonic antigen (CEA). CEA and CK20 mRNA levels were quantified using a real-time qRT-PCR system.

RESULTS

For gastric carcinoma the FPTC positivity rate acquired by cytology, immunofluorescence and qRT-PCR was 14.8%, 14.8%, and 78% and for colorectal carcinoma was 0%, 17%, and 42%, respectively. qRT-PCR positivity was correlated with a poor cancer-specific survival and time-to-recurrence rates in both gastric and colorectal carcinoma.

CONCLUSIONS

Epithelial immunoenrichment and immunofluorescence analysis allows unequivocal identification of the FPTC. The real time qRT-PCR showed higher sensitivity for the detection of CEA and CK20 mRNA levels and confirmed its prognostic value in gastrointestinal cancers.

Enhancement of metastatic ability by ectopic expression of ST6GalNAcI on a gastric cancer cell line in a mouse model

ST6GalNAcI is a sialyltransferase responsible for the synthesis of sialyl Tn (sTn) antigen which is expressed in a variety of adenocarcinomas including gastric cancer especially in advanced cases, but the roles of ST6GalNAcI and sTn in cancer progression are largely unknown. We generated sTn-expressing human gastric cancer cells by ectopic expression of ST6GalNAcI to evaluate metastatic ability of these cells and prognostic effect of ST6GalNAcI and sTn in a mouse model, and identified sTn carrier proteins to gain insight into the function of ST6GalNAcI and sTn in gastric cancer progression. A green fluorescent protein-tagged human gastric cancer cell line was transfected with ST6GalNAcI to produce sTn-expressing cells, which were transplanted into nude mice. STn-positive gastric cancer cells showed higher intraperitoneal metastatic ability in comparison with sTn-negative control, resulting in shortened survival time of the mice, which was mitigated by anti-sTn antibody administration. Then, sTn-carrying proteins were immunoprecipitated from culture supernatants and lysates of these cells, and identified MUC1 and CD44 as major sTn carriers. It was confirmed that MUC1 carries sTn also in human advanced gastric cancer tissues. Identification of sTn carrier proteins will help understand mechanisms of metastatic phenotype acquisition of gastric cancer cells by ST6GalNAcI and sTn.

Analysis for the combination expression of CK20, FABP1 and MUC2 is sensitive for the prediction of peritoneal recurrence in gastric cancer

Prediction of peritoneal recurrence in gastric cancer patients is important for application of adjuvant chemotherapy. After surgery, occasional patients have peritoneal recurrence despite negative cytology of the peritoneal washings. Thus, molecular detection of a subliminal number of cancer cells in peritoneal washings may overcome the sensitivity limitation of conventional cytology. In this study, expressions of five specific marker genes, namely, TFF1, TFF2, CK20, FABP1 and MUC2, were evaluated for their usefulness as markers of micro-dissemination. It was found that reverse transcriptase-polymerase chain reaction for these five genes yielded results highly specific for the depth of invasion and disease stage. Furthermore, the expression of CK20, FABP1 and MUC2 was a reliable prognostic indicator of peritoneal metastasis. Our results suggest that evaluation of the expression of CK20, FABP1 and MUC2 in peritoneal washings is a useful tool for identifying patients at high risk of peritoneal recurrence who may need adjuvant chemotherapy.

Oncofetal protein, IMP-3, a potential marker for prediction of postoperative peritoneal dissemination in gastric adenocarcinoma

BACKGROUND

The aim of this study was to determine the expression of insulin-like growth factor-II messenger RNA (mRNA)-binding protein-3 (IMP-3) and its clinical significance in gastric cancers, as well the prognostic value of its expression in the peritoneal lavage fluid after surgery.

METHODS

IMP-3 expression was examined by immunohistochemistry in 96 primary gastric tumors. IMP-3 mRNA expression in peritoneal lavage fluid obtained at laparotomy was determine by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Positive staining for IMP-3 was observed in 74% (71/96) of the tumors. IMP-3 expression in gastric tumors correlated significantly with worst overall survival (OS) and recurrence-free survival. Multivariate analyses identified pathological N stage and IMP-3 expression as significant independent prognostic factors for disease-free survival. Eight (28%) of 36 peritoneal lavage samples were cytologically negative but positive for IMP-3 mRNA expression by RT-PCR. The OS of patients with IMP-3-positive peritoneal lavage was significantly worse than of those with negative expression.

CONCLUSIONS

IMP-3 expression in primary gastric tumors was an independent poor prognostic factor. IMP-3 mRNA expression in peritoneal lavage fluid was a predictor of recurrence after surgery in gastric cancer and a marker of poor prognosis.

Dissemination of free cancer cells from the gastric lumen and from perigastric lymphovascular pedicles during radical gastric cancer surgery

BACKGROUND

Manipulation and improper handling of a tumor during surgery may increase the risk of cancer cell dissemination after a curative gastrectomy. This study investigated the effect of improper handling of lymphovascular pedicles of stomach on tumor spillage during surgical procedure.

METHODS

Thirty-eight gastric cancer patients were enrolled. Three pairs of wash samples were obtained from each patient: (1) intraperitoneal wash samples obtained before (P0) and after gastrectomy (P1), (2) intragastric wash samples obtained before any manipulation (G0) and just before resection of the stomach (G1), and (3) ex vivo wash samples obtained by rinsing resected stomach with the lymphovascular pedicles closed by clips (S0) or with the pedicles open (S1). Cytologic examination was performed from all washes, and real-time reverse transcriptase-polymerase chain reaction analysis for carcinoembryonic antigen was performed from washes P0, P1, S0, and S1.

RESULTS

Cytologic examination detected cancer cells in 34.2% (13 of 38) of G0 samples and in 39.5% (15 of 38) of G1 samples. The rate of conversion from G0-negative to G1-positive increased as T stage increased. Cytologic examination detected cancer cells in 2.6% (1 of 38) of S0 samples and in 13.2% (5 of 38) of S1 samples. The carcinoembryonic antigen mRNA level of the S1 sample was 2-fold greater than that of the S0 sample in 50.0% (7 of 14).

CONCLUSIONS

Free cancer cells can be released from gastric lumen or lymphovascular pedicles opened during gastric cancer surgery, especially in advanced-stage disease. Care should be taken to minimize spillage from the gastric lumen and lymphovascular pedicles.

Prognostic factors of T4 gastric cancer patients undergoing potentially curative resection

AIM: To investigate the prognostic factors of T4 gastric cancer patients without distant metastasis who could undergo potentially curative resection.

METHODS: We retrospectively analyzed the clinical data of 71 consecutive patients diagnosed with T4 gastric cancer and who underwent curative gastrectomy at our institutions. The clinicopathological factors that could be associated with overall survival were evaluated. The cumulative survival was determined by the Kaplan-Meier method, and univariate comparisons between the groups were performed using the log-rank test. Multivariate analysis was performed using the Cox proportional hazard model and a step-wise procedure.

RESULTS: The study patients comprised 53 men (74.6%) and 18 women (25.4%) aged 39-89 years (mean, 68.9 years). Nineteen patients (26.8%) had postoperative morbidity: pancreatic fistula developed in 6 patients (8.5%) and was the most frequent complication, followed by anastomosis stricture in 5 patients (7.0%). During the follow-up period, 28 patients (39.4%) died because of gastric cancer recurrence, and 3 (4.2%) died because of another disease or accident. For all patients, the estimated overall survival was 34.1% at 5 years. Univariate analyses identified the following statistically significant prognostic factors in T4 gastric cancer patients who underwent potentially curative resection: peritoneal washing cytology (P < 0.01), number of metastatic lymph nodes (P < 0.05), and venous invasion (P < 0.05). In multivariate analyses, only peritoneal washing cytology was identified as an independent prognostic factor (HR = 3.62, 95% CI = 1.37-9.57) for long-term survival.

CONCLUSION: Positive peritoneal washing cytology was the only independent poor prognostic factor for T4 gastric cancer patients who could be treated with potentially curative resection.

Phase II clinical trial of postoperative S-1 monotherapy for gastric cancer patients with free intraperitoneal cancer cells detected by real-time RT-PCR

BACKGROUND

We have previously reported the molecular detection of peritoneal micrometastases in patients with gastric cancer by quantifying carcinoembryonic antigen (CEA) mRNA in the peritoneal washes. Patients with CEA mRNA exceeding a cutoff value have a significant risk for developing peritoneal carcinomatosis, but optimal treatment for this population remains unknown.

METHODS

CEA mRNA (+) patients with gastric cancer were treated postoperatively with S-1 monotherapy. Overall survival, the primary endpoint of this phase II trial, was compared with the historical control, which is comprised of CEA mRNA (+) patients who were not given postoperative chemotherapy.

RESULTS

A total of 32 patients with CEA mRNA (+) gastric cancer were enrolled. Twelve patients (37.5%) relapsed; ten showed peritoneal relapse. Three-year survival was similar between the study population and the historical control (67.3% vs. 67.1%, respectively).

CONCLUSIONS

S-1 monotherapy, which significantly reduced risk for recurrence in stage II/III gastric carcinoma in another phase III trial, seems not to be as effective in eradicating free cancer cells in the abdominal cavity.

Peritoneal wash cytology in gastric carcinoma. Prognostic significance and therapeutic consequences

BACKGROUND AND AIMS

The prognosis of patients with gastric cancer is poor, even following curative resection, and is related primarily to the extent of disease at presentation. In locally advanced gastric tumors, peritoneal lavage cytology (PLC) is a relevant prognostic factor. The Authors present their results of peritoneal washing cytology, evaluating the prognostic value of this technique, and discussing the clinical impact.

PATIENTS AND METHODS

From July 2003 to May 2008, results of PLC in 64 patients with histologically proven primary gastric adenocarcinomas were analyzed. At laparotomy the abdomen was irrigated with 200 ml of normal saline, and ≥50 ml were aspirated and examined by means of cytology and immunocytopathology.

RESULTS

PLC was positive in 7 cases (11%). Overall, 86% of patients with a positive PLC had a pT3/pT4 tumor and 100% with a positive PLC had an N-positive tumor (p < 0.001); 71% of patients with a positive PLC had a grade G3/G4 tumor (p = 0.001). At a median follow-up of 32 months, the cumulative 5-year survival was 28%. The median survival of patients presenting positive PLC (19 months) was significantly lower than that of patients with negative peritoneal cytology (38 months) (p = 0.0001). Multivariate analysis identified cytology as a significant predictor of outcome (p = 0.018).

CONCLUSIONS

Results in the present series demonstrated that patients with a positive peritoneal cytology had advanced disease and poor prognosis, thus indicating that patients with locally advanced gastric cancer should undergo staging laparoscopy and PLC examination in order to select those requiring more aggressive treatment. Future therapeutic strategies should include PLC examination in preoperative staging, in order to select patients for more aggressive treatment.

Prognostic significance of free peritoneal tumor cells in the peritoneal cavity before and after neoadjuvant chemotherapy in patients with gastric carcinoma undergoing potentially curative resection

BACKGROUND

Free peritoneal tumor cells (FPTCs) are an independent prognostic factor in patients undergoing curative resection for gastric carcinoma. Whether neoadjuvant chemotherapy (NAC) can eliminate FPTCs in the peritoneal lavage remains unclear. The aim of the study was to determine the effect of NAC on FPTCs.

METHODS

From 1994 to 2000, data from a total of 61 patients with resectable gastric cancer were analyzed. Peritoneal cytology was performed before NAC at laparoscopy and at tumor resection. A minimum of 6 weeks of NAC, consisting of cisplatin, folinic acid, and fluorouracil, was administered. FPTCs were detected immunohistochemically with Ber-EP4 antibody.

RESULTS

No FPTCs could be detected in 42 patients (69%), compared to 19 (31%) with FPTCs before NAC. During chemotherapy, 10 (24%) of 42 patients developed FPTCs, and 7 (37%) of 19 patients reverted from positive to negative. Patients who became FPTC negative (n = 7) showed an improved median survival (36.1 months) and a longer 2-year survival (71.4%) compared to FPTC-positive patients before and after NAC (n = 12), with a median survival of 9.2 months and a 2-year survival rate of 25%. In contrast, patients who reverted from FPTC negative to positive during NAC (n = 10) had a median survival of 18.5 months and a 2-year survival of only 20%. Multivariate analysis identified ypN category and FPTC change as independent prognostic factors.

CONCLUSIONS

NAC for patients with positive cytology could lead to FPTC negativity in a subset of patients and improve their prognosis. However, NAC might be a risky strategy for almost one-quarter of patients whose disease develops positive cytology.

E7050: a dual c-Met and VEGFR-2 tyrosine kinase inhibitor promotes tumor regression and prolongs survival in mouse xenograft models

c-Met is the cellular receptor for hepatocyte growth factor (HGF) and is known to be dysregulated in various types of human cancers. Activation of the HGF/c-Met pathway causes tumor progression, invasion, and metastasis. Vascular endothelial growth factor (VEGF) is also known as a key molecule in tumor progression through the induction of tumor angiogenesis. Because of their key roles in tumor progression, these pathways provide attractive targets for therapeutic intervention. We have generated a novel, orally active, small molecule compound, E7050, which inhibits both c-Met and vascular endothelial growth factor receptor (VEGFR)-2. In vitro studies indicate that E7050 potently inhibits phosphorylation of both c-Met and VEGFR-2. E7050 also potently represses the growth of both c-met amplified tumor cells and endothelial cells stimulated with either HGF or VEGF. In vivo studies using E7050 showed inhibition of the phosphorylation of c-Met and VEGFR-2 in tumors, and strong inhibition of tumor growth and tumor angiogenesis in xenograft models. Treatment of some tumor lines containing c-met amplifications with high doses of E7050 (50-200 mg/kg) induced tumor regression and disappearance. In a peritoneal dissemination model, E7050 showed an antitumor effect against peritoneal tumors as well as a significant prolongation of lifespan in treated mice. Our results indicate that E7050 is a potent inhibitor of c-Met and VEGFR-2 and has therapeutic potential for the treatment of cancer.

Extensive intraoperative peritoneal lavage as a standard prophylactic strategy for peritoneal recurrence in patients with gastric carcinoma

OBJECTIVE

This prospective randomized multicenter study aims to evaluate the efficacy of extensive intraoperative peritoneal lavage followed by intraperitoneal chemotherapy (EIPL-IPC) on the overall 5-year survival of advanced gastric cancer patients with intraperitoneal free cancer cells without overt peritoneal metastasis (CY+/P-). The study also aims to determine the merit and reliability of EIPL-IPC therapy as a prophylactic strategy for peritoneal metastasis.

SUMMARY BACKGROUND DATA

Although the prognosis of advanced gastric cancer patients with CY+/P- is extremely poor, a suitable standard regimen for treating such patients has not yet been established.

METHODS

A total of 88 patients with CY+/P- from 1522 patients with advanced gastric cancer at multicenters were enrolled in this study and were randomly allocated to 3 groups: surgery alone group, surgery plus intraperitoneal chemotherapy (IPC) group, and surgery plus EIPL and IPC (EIPL-IPC) group. Prognostic significance of EIPL-IPC therapy was evaluated by Kaplan-Meier curves, and its value as an independent prognostic factor was assessed by univariate and multivariate analyses.

RESULTS

The overall 5-year survival rate of the patients with EIPL-IPC was 43.8%, and this data were significantly better than that of the IPC group (4.6%, P < 0.0001) and the surgery alone group (0%, P < 0.0001). Among various recurrent patterns, the EIPL-IPC group had a significantly lower incidence of peritoneal recurrence than both of the other groups (P < 0.0001). Univariate and multivariate analyses revealed that EIPL was the most significant impact factor.

CONCLUSIONS

The present study clearly revealed that EIPL-IPC therapy significantly improved the 5-year survival span of advanced gastric cancer patients with CY+/P-. Thus, EIPL-IPC therapy is strongly recommended as a standard prophylactic strategy for peritoneal dissemination.

Prognostic significance of peritoneal tumour cells identified at surgery for colorectal cancer

BACKGROUND

The prognostic significance of intraperitoneal tumour cells (IPCs) in colorectal cancer is not clear. This study aimed to determine whether detection of IPCs could be used a prognostic marker for selecting patients at high risk of recurrence.

METHODS

The study included 226 patients with colorectal cancer who underwent elective resection. Clinical variables, including the presence of IPCs, were analysed for their prognostic significance.

RESULTS

Thirty-three patients (14.6 per cent) were positive for IPCs. Univariable analysis indicated that the presence of IPCs was a significant prognostic factor in patients with stage III colorectal cancer; the 5-year disease-specific survival rate was 14 per cent in IPC-positive patients versus 79 per cent in those without IPCs (P < 0.001). Multivariable analysis showed that IPC positivity was the most robust prognostic factor in stage III disease (hazard ratio 2.2; P = 0.003), whereas nodal category (N1 or N2) showed no significant association with prognosis. In addition, IPCs were associated with haematogenous recurrence (P = 0.004) rather than peritoneal or local recurrence (P = 0.077) in patients with stage III disease.

CONCLUSION

The presence of IPCs is a significant prognostic factor in patients with stage III colorectal cancer.

Detection of micrometastases in peritoneal washings of gastric cancer patients by the reverse transcriptase polymerase chain reaction

BACKGROUND

Gastric cancer patients with positive (+) peritoneal cytology have a prognosis similar to stage IV patients. We studied the ability of quantitative reverse transcriptase polymerase chain reaction (RT-PCR) to detect peritoneal micrometastases in patients undergoing staging laparoscopy.

METHODS

Peritoneal washings were obtained prospectively from 34 patients with gastric adenocarcinoma undergoing staging laparoscopy and 6 patients undergoing laparoscopy for benign disease. Each sample underwent cytologic and RT-PCR analysis for tumor markers: carcinoembryonic antigen (CEA), cytokeratin 20 (CK20), survivin, and MUC2. Markers were evaluated on the basis of their deviance from the ideal marker.

RESULTS

Pathologic stages for the gastric cancer patients were: stage I, 9 (27%); stage II, 7 (21%); stage III, 15 (44%); and stage IV, 3 (9%). The four cytology (+) patients were: stage II, 1; stage III, 1; and stage IV, 2. Fifteen patients were RT-PCR (+), including all cytology (+) patients. The optimal threshold for cycle amplification was 35, based on a receiver operating characteristic curve. CEA had the smallest deviance.

CONCLUSION

RT-PCR using a panel of tumor markers, including CEA, detects (+) cytology. The clinical significance of "false-positive" overexpression of CEA, survivin, or CK20 but cytology (-) remains to be defined. RT-PCR could represent a more sensitive method than cytology for detection of subclinical peritoneal tumor dissemination; this may be useful in improving patient selection for operative management and clinical trials.

Genetic detection of free cancer cells in the peritoneal cavity of the patient with gastric cancer: present status and future perspectives

The purpose of this review is to examine the current status and future perspectives of the molecular analysis of peritoneal lavage fluid in patients with gastric cancer. During the past 10 years, the polymerase chain reaction (PCR) has been applied for the molecular detection of free cancer cells in the abdominal cavity of patients with gastric cancer, and its clinical significance in establishing the presence of peritoneal dissemination has been assessed by several groups especially in Japan. The majority of these studies have confirmed the predictive value of the molecular detection of peritoneal metastasis and recurrence using peritoneal lavage fluid. Based on these findings, since April 2006, the genetic diagnosis of body fluids has been included in the Japanese Government public health insurance program for patients with solid tumors. However, there are still many obstacles to overcome before the genetic diagnosis of micrometastasis can be considered a routine laboratory assay. Here we review the importance of the molecular detection of cancer cells in the abdominal cavity, and the molecular techniques used for such diagnosis; we also provide some clinical examples to illustrate the value of molecular diagnosis.

Detection of micrometastases in peritoneal washings of pancreatic cancer patients by the reverse transcriptase polymerase chain reaction

OBJECTIVE

Pancreatic cancer patients with positive (+) peritoneal cytology have a prognosis similar to stage IV patients. We studied the ability of quantitative real time-polymerase chain reaction (RT-PCR) to detect micrometastases in patients undergoing staging laparoscopy.

METHODS

Peritoneal washes were obtained prospectively from 35 consecutive patients with pancreatic adenocarcinoma undergoing staging laparoscopy and 16 patients undergoing laparoscopy for benign disease. Each sample was assessed by cytologic examination and RT-PCR analysis for tumor markers: CEA, CK7, Kras2, and MUC1. Markers and their combinations were evaluated on the basis of their deviance from the ideal marker.

RESULTS

Pathologic stages for pancreatic cancer patients were: 1A-1 (3%), IB-1 (3%), IIA-5 (15%), IIB-13 (38%), III-5 (15%), IV-9 (26%). Eight patients were cytology (+) and stages IIA-1, IIB-2, IV-5. Twenty-five patients were RT-PCR (+). The optimal threshold for cycle amplification was 35 based on a receiver operating characteristic curve. CEA had the best profile of sensitivity, specificity, PPV, NPV, and the smallest deviance.

CONCLUSION

RT-PCR using a panel of tumor markers, including CEA, was comparable in sensitivity, specificity, PPV, and NPV to cytology. RT-PCR could represent a more sensitive method for detection of subclinical peritoneal tumor dissemination; this may be useful in patient selection for operative management and clinical trials.

A carbohydrate recognition-based drug delivery and controlled release system using intraperitoneal macrophages as a cellular vehicle

The lymphoid tissue in the omentum, at the so-called milky spots, is known as an initial place for disseminated cancer cells to develop into solid tumors. In the present study, i.p. macrophages significantly took up oligomannose-coated liposomes (OMLs) that were injected into the peritoneal cavity, and then gradually accumulated in the omentum and the other lymphoid tissues within 24 hours of i.p. injection of OMLs. When 5-fluorouracil (5-FU) was encapsulated in the OMLs, >60% of administered 5-FU accumulated in the omentum. Treatment of macrophages at 39 degrees C for 30 minutes led to the release of 5-FU from the macrophages, suggesting that controlled release from macrophages could be achieved by mild hyperthermia. We encased magnetic nanoparticles, which are known to convert electromagnetic energy to heat in the OMLs to achieve in vivo hyperthermia at the site. Using this system in a mouse i.p. metastasis model, we successfully controlled tumor development by coadministration of OML-encased 5-FU and OML-encased magnetic nanoparticles, followed by treatment with an alternating magnetic field. No apparent reduction was seen in tumor growth with the administration of OML-encased magnetic nanoparticles or OML-encased 5-FU alone. Thus, we have established the use of i.p. macrophages as a novel drug delivery system for the control of cancer metastatic to milky spots.

Prognostic impact of PCR-based identification of isolated tumour cells in the peritoneal lavage fluid of gastric cancer patients who underwent a curative R0 resection

Identification of cancer cells in the peritoneal cavity could influence therapy and outcome of gastric carcinoma patients. The objective of this study was to evaluate the clinical impact of the real-time quantitative polymerase chain reaction-(PCR) based identification of isolated tumour cells in the peritoneal lavage fluid of gastric carcinoma. The peritoneal lavage fluid of 116 patients with gastric cancer was sampled at laparotomy. After RNA extraction and reverse transcription, real-time quantitative PCR was performed using the primers and probes for carcinoembryonic antigen (CEA) and cytokeratin-20 (CK20). When either the CEA mRNA or CK20 mRNA level of the sample was over the cutoff value, the sample was determined to be PCR-positive. Forty-six (40%) of the 116 patients were PCR-positive and 30 (65%) of the 46 PCR-positive patients died as a result of recurrent peritoneal dissemination. The prognosis of the 46 PCR-positive patients was significantly (P<0.001) worse than that of 70 PCR-negative patients. Furthermore, in 80 of the cases with a curative R0 resection, 15 of the patients with PCR-positive findings had a significantly (P<0.001) poorer prognosis than the 65 PCR-negative patients. The prognosis of the PCR-positive patients was significantly poorer than that of the PCR-negative patients in the T3 (P<0.0001) and T4 (P=0.048) subgroups. In a multivariate analysis of the 80 cases with a curative R0 resection, the real-time quantitative RT–PCR (CEA and/or CK20) levels indicated that they were independent prognostic factors. The real-time quantitative RT–PCR analysis of the CEA and/or CK20 transcripts in the peritoneal lavage fluid is useful for predicting the peritoneal recurrence in patients who are undergoing a curative resection for gastric cancer.

Comparative analysis of intraperitoneal minimal free cancer cells between colorectal and gastric cancer patients using quantitative RT-PCR: possible reason for rare peritoneal recurrence in colorectal cancer

Peritoneal recurrence has a much lower incidence in colorectal cancer (CRC) patients than gastric cancer (GC) patients. The aim of this study is to clarify the reason for the rare peritoneal recurrence in CRC as compared with GC. The incidence and the abundance of free tumor cells in the peritoneal lavages from 102 CRC and 126 GC patients who underwent curative surgery were assessed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) with carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20) as genetic markers. Prognostic significance of CEA and CK20 mRNA was also compared between CRC and GC after 2 years of follow-up by Kaplan-Meyer method with overall and peritoneal recurrence-free survival as endpoints. Positivity rate and average values of CEA and CK20 mRNA in peritoneal lavages of CRC patients, which are correlated to the depth of tumor invasion (pT category), were essentially the same as those of GC cases. Overall survival was significantly (marginally) worse in CEA mRNA (CK20 mRNA)-positive CRC patients than negatives like GC. However, peritoneal recurrence-free survival was not different between CEA (CK20) mRNA-positive and -negative CRC patients, in quite contrast to GC cases. Multivariate analysis showed that CEA mRNA was an independent prognostic factor for overall survival in GC patients, but not in CRC patients. These results suggest that the rare peritoneal recurrence in CRC patients is not due to the low incidence or the small number of intraperitoneal free cancer cells, but more likely reflects due to the low-peritoneal metastatic potential of CRC cells.

Prognostic significance of peritoneal washing cytology in Thai patients with gastric adenocarcinoma undergoing curative D2 gastrectomy

BACKGROUND

The aim of the present study was to determine the prognostic significance of peritoneal washing cytology (PWC) among Thai patients with gastric adenocarcinoma.

METHODS

Medical charts of 97 patients with gastric adenocarcinoma who underwent curative D2 gastrectomy between October 1995 and September 2005 were reviewed.

RESULTS

A total of 22 patients (23%) had positive PWC. Factors significantly associated with positive PWC included tumor location, macroscopic findings, histology, depth of tumor invasion, nodal involvement, TNM stage, and angiolymphatic invasion. Positive PWC was found only in tumors invading the serosa. All patients with positive PWC developed peritoneal recurrence. The sensitivity and specificity of positive PWC in predicting peritoneal recurrence were 61% and 100%, respectively. The overall 5-year survival rates for patients with positive and negative PWC were 0% and 75%, respectively.

CONCLUSION

Gastric adenocarcinoma with positive PWC should be considered stage IV disease. PWC should be included in the staging of gastric adenocarcinoma.

Distribution of free cancer cells in the abdominal cavity suggests limitations of bursectomy as an essential component of radical surgery for gastric carcinoma

BACKGROUND

Bursectomy, which has been performed so as to resect peritoneal deposits disseminated within the omental bursa, is considered as an essential component of radical surgery for gastric carcinoma in Japan. Bursectomy has also been described in the Japanese Treatment Guidelines for Gastric Carcinoma as a mandatory procedure for the treatment of serosa-positive cancer. However, no evidence to support the prognostic significance of this procedure has been reported to date.

METHODS

Cytologic examination and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of the peritoneal washes obtained from the Douglas pouch, left subphrenic cavity, and inside the omental bursa were performed for 136 patients who underwent potentially curative surgery for gastric carcinoma.

RESULTS

Carcinoembryonic antigen (CEA) or cytokeratin (CK) 20 mRNA was detected in one or more samples from the three different sites of peritoneal washes in 43 of the 136 patients. In 14 patients, the mRNAs were detected in samples obtained from the bursa omentalis (10.3% of all patients and 32.6% of patients with positive RT-PCR results). In 12 of these 14 patients, the mRNAs were also detected in samples taken from either or both of the remaining two sites. Only in the 2 other patients was the sample only from inside the omental bursa positive for CEA.

CONCLUSION

It is unlikely that viable cancer cells disseminated into the bursa remain restricted to this cavity without migrating into the free abdominal cavity. Routine bursectomy may not be an essential procedure for resecting gastric cancer, from the viewpoint of eliminating microscopic peritoneal deposits within the omental bursa.

Efficacy of S-1 for patients with peritoneal metastasis of gastric cancer

BACKGROUND

This study was designed to examine the efficacy and compliance of S-1 for the patients with peritoneal metastasis of gastric cancer.

METHODS

Sixteen consecutive patients with peritoneal metastasis of gastric cancer were treated with S-1. Their survival was compared with that of the historical control group (25 patients). Thymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase and orotate phosphoribosyl transferase mRNA expression in the tumor were evaluated.

RESULTS

The median survival time of S-1-treated patients was 550 days, which was significantly longer than that of the historical control group (215 days). We elucidated some factors to prolong the survival of the patients treated with S-1 for peritoneal metastasis: peritoneal metastasis without other distant metastases, the combination of S-1 treatment and gastrectomy, and low expression of thymidine phosphorylase mRNA in primary tumors.

CONCLUSIONS

S-1 showed a surprisingly long-term survival with minimum toxicity in patients with peritoneal metastasis of gastric cancer.

Peritoneal Cytology Does Not Increase the Prognostic Information Provided by TNM in Gastric Cancer

BACKGROUND

This study aimed at verifying whether peritoneal cytology could improve the prognostic information provided by TNM staging in gastric cancer patients.

METHOD

The presence of free peritoneal tumor cells was investigated in 168 patients who underwent curative resection for gastric cancer from January 1992 to July 2002 in Verona, Italy. The influence of peritoneal cytology on survival was evaluated by a Cox regression model, controlling for potential confounders.

RESULTS

Twenty-three patients (14%) had positive peritoneal cytology. Patients with positive lavage were more likely to present serosal infiltration (100 vs. 46%) and nodal metastases (91 vs. 67%; P < 0.001). Positive lavage was associated with a very poor prognosis: 3-year survival was only 9% (95% CI 2-27%) when peritoneal cancer cells had been detected, whereas survival reached 50% (95% CI 42-59%) in patients with a negative cytology. In multivariate survival analysis, peritoneal cytology was an independent predictor of mortality when controlling for sex, age, site, histology, and nodal metastases, but not when adjusting also for depth of tumor invasion (RR of positive versus negative = 1.2, 95% CI 0.7-2.0). Similarly, the influence of peritoneal cytology on survival was no longer significant when univariate analysis was restricted to T3/T4 patients (RR = 1.5, 0.9-2.5).

CONCLUSIONS

Positive peritoneal cytology was a marker of poor prognosis in gastric cancer patients. Nevertheless, peritoneal lavage did not increase the prognostic information already provided by the TNM staging system in this Italian series.