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

Study protocol of a phase II clinical trial evaluating the efficacy of neoadjuvant intraperitoneal and systemic albumin-bound paclitaxel combined with camrelizumab and S-1 in the treatment of patients with exfoliative cell-positive gastric cancer

Background

Currently, gastric cancer with positive lavage cytology without gross peritoneal dissemination (GC-CY1) is a special type of metastatic form with poor prognosis. Consensus guidelines on treatment strategies for patients with GC-CY1 have not been established. This study involves a single-arm, prospective, phase II clinical trial to examine the efficacy and safety of neoadjuvant intraperitoneal and systemic (NIPS) albumin-bound paclitaxel combined with Camrelizumab and S-1 in the treatment of GC-CY1 patients.

Methods/design

This is a prospective single-center exploratory study, and the primary endpoints of the trial are R0 resection rate and conversion rate of abdominal free cancer cells (FCCs), with secondary endpoints of 3-year progression-free survival (PFS); 3-year overall survival (OS); objective remission rate (ORR); disease control rate (DCR); safety and TRG classification.

Discussion

This study is the first to apply NIPS albumin-bound paclitaxel combined with Camrelizumab and S-1 to the conversion therapy of GC-CY1 patients. It is speculated that this combination of regimens will increase the negative conversion rate of FCCs by 20%, which will provide innovative insights into conversion treatment ideas for GC-CY1 patients to be managed in a more comprehensive and optimized manner.

Clinical trial registration

http://clinicaltrials.gov/, identifier NCT05410847.

Utility of Molecular Analysis of Peritoneal Fluid in Staging Laparoscopy of Advanced Esophagogastric Junction and Gastric Cancer Prior to Neoadjuvant Treatment

PURPOSE

Molecular analysis of peritoneal fluid in staging laparoscopy of gastric cancer is performed to improve the detection of free intraperitoneal tumor cells. Nevertheless, its significance is controversial, especially in patients with negative cytology but positive molecular analysis. The aim of this study was to analyze the sensitivity of molecular analysis and its prognostic value.

METHODS

A retrospective analysis from April 2011 to October 2019 was performed. Cytology (Cyt) and molecular analysis were analyzed by real-time reverse transcriptase polymerase chain reaction (RT-PCR) of the carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20) tumor makers.

RESULTS

During the study period, 138 staging laparoscopies were performed. Macroscopic carcinomatosis was found in 12.3%. Of the remaining 87.7%, 9.9% were Cyt + and 11.6% were Cyt- RT-PCR + . Of the latter, 9 responded to chemotherapy and underwent radical surgery. The sensitivity of cytology and molecular analysis was 0.70 and 0.76, respectively (p = 0.67). The 2-year overall survival (OS) of Cyt- RT-PCR + vs. Cyt + was similar (p = 0.1). The 2-year OS of Cyt-RT-PCR + subgroup who underwent radical surgery vs. Cyt-RT-PCR- patients was similar (p = 0.69), but disease-free survival was shorter in the first group (p = 0.005).

CONCLUSION

Our results show that the sensitivity of molecular analysis is similar to that of cytology. The prognostic value of positive molecular analysis was similar to positive cytology in terms of 2-year overall survival, except in the subgroup of operated patients in whom the overall survival was similar to that of those with a negative molecular analysis, albeit with a shorter disease-free survival.

Novel CT based clinical nomogram comparable to radiomics model for identification of occult peritoneal metastasis in advanced gastric cancer

BACKGROUND

Occult peritoneal metastasis (OPM) in advanced gastric cancer (AGC) patients remains a major diagnostic challenge. The aim of this study was to develop novel predictive models for identification of OPM in AGCs.

METHOD

A total of 810 patients with primary AGCs from two hospitals were retrospectively selected and divided into training (n = 393), internal validation (n = 215) and external validation cohorts (n = 202). CT based machine learning models were built and tested to predict the OPM status in AGCs., which are 1) Radiomic signatures: using venous CT imaging features, 2) Clinical models: integrating tumor location, differentiation and extent of serosal exposure, and 3) Radiomics models: combining of radiomic signature, tumor location and tumor differentiation.

RESULT

Total incidence of OPM was 8.27% (67/810). Clinical models yielded comparable classification accuracy with the corresponding radiomics models with similar AUCs (0.902-0.969 vs. 0.896-0.975) while the radiomic signatures showed relatively low AUCs of 0.863-0.976. In the case where the specificity is higher than 90%, the overall sensitivity of clinical model and radiomics model for OPM positive cases was 76.1% (51/67) and 82.1% (55/67). A nomogram based on the logistic clinical model was drawn to facilitate the usage and verification of the clinical model.

CONCLUSION

Both the novel CT based clinical nomogram and radiomics model provide promising method to yield high accuracy in identification of OPM in AGC patients.

Circulating methylated THBS1 DNAs as a novel marker for predicting peritoneal dissemination in gastric cancer

Objectives

Thrombospondin 1 (THBS1) is known to play a key role in tumor metastasis, and aberrant DNA methylation is one of the mechanisms regulating THBS1. The present study investigated whether methylated THBS1 in circulating cell‐free DNA from preoperative peritoneal lavage fluid (PPLF) and peripheral blood could be used as a potential biomarker for predicting peritoneal dissemination in gastric cancer (GC) patients.

Methods

The status of THBS1 methylation was detected by quantitative methylation‐specific PCR (MSP) in tumor tissues, paired PPLF, and serum from 92 GC patients. The correlation between methylated THBS1 levels and peritoneal dissemination of GC was studied, and its diagnostic value for predicting peritoneal dissemination was clarified by the receiver operating characteristic (ROC) curve.

Results

Aberrant THBS1 methylation in tumor tissues was significantly higher than that in paracancerous normal tissues (p < 0.0001). No THBS1 methylation was found in 40 healthy controls, and partial methylation was detected in 3 of 48 patients with chronic non‐atrophic gastritis. The frequency of THBS1 methylation in pairing PPLF and serum from 92 GC patients was 52.2% (48/92) and 58.7% (54/92), respectively. The results of methylated THBS1 in pairing PPLF and serum were similar to those of tumor tissues. Aberrant THBS1 methylation in tumor tissues and pairing PPLF or serum was closely related to peritoneal dissemination, tumor progression, and poor prognosis (all p < 0.0001).

Conclusion

Circulating methylated THBS1 DNAs in PPLF/serum may predict peritoneal dissemination, a potential poor prognostic factor for GC patients.

Clinical importance of carcinoembryonic antigen messenger RNA level in peritoneal lavage fluids measured by transcription-reverse transcription concerted reaction for advanced gastric cancer in laparoscopic surgery

BACKGROUND

Transcription-reverse transcription concerted reaction (TRC) is recognized as a useful method for detecting free cancer cells in the peritoneal cavity and predicting peritoneal recurrence in patients with gastric cancer. Nonetheless, the clinical significance of TRC in laparoscopic surgery remains unclear. This study aimed to evaluate the clinical importance of carcinoembryonic antigen (CEA) messenger RNA (mRNA) level in peritoneal lavage fluids measured by TRC in laparoscopic surgery for locally advanced gastric cancer.

METHODS

We enrolled patients with locally advanced gastric cancer who underwent laparoscopic gastrectomy. Peritoneal lavage fluids were collected prior to gastrectomy, and the TRC method was employed to quantify CEA mRNA in peritoneal washes. Overall survival (OS), recurrence-free survival (RFS), and peritoneal recurrence-free survival (PRFS) were analyzed using the Kaplan-Meier method and compared using the log-rank test. Adjusted Cox proportional hazards regression models were used to calculate the hazard ratios (HRs) for CEA mRNA positivity.

RESULTS

A total of 100 patients were analyzed in this study. Overall, 22 patients (22%) exhibited CEA mRNA positivity in peritoneal lavage fluids, as measured by TRC. No significant association between CEA mRNA levels and clinicopathological characteristics was observed. Patients who were CEA mRNA-positive in peritoneal lavage fluids had significantly worse OS, RFS, and PRFS than those who were CEA mRNA-negative (p = 0.0059, p < 0.0001, and p = 0.0022, respectively). In the univariate Cox model, the HR for all-cause mortality in CEA mRNA-positive versus CEA mRNA-negative patients was 3.60 (95% CI, 1.33-9.55; p = 0.0129). Multivariate analysis revealed that CEA mRNA positivity was a significant independent factor for recurrence.

CONCLUSIONS

TRC enables the detection of free cancer cells in the peritoneal cavity and CEA mRNA levels can help predict the prognosis, even in laparoscopic gastrectomy.

Impact of preoperative chemotherapy as initial treatment for advanced gastric cancer with peritoneal metastasis limited to positive peritoneal lavage cytology (CY1) or localized peritoneal metastasis (P1a): a multi-institutional retrospective study

BACKGROUND

Gastric cancer (GC) patients with peritoneal metastasis are defined as stage IV in the Japanese classification of GC. For patients with peritoneal metastasis limited to positive peritoneal lavage cytology (CY1) and/or localized peritoneal metastasis (P1a), gastrectomy followed by S1 monotherapy is one of the most widely accepted therapeutic strategy in Japan. This study investigated the efficacy of preoperative chemotherapy as initial treatment in GC patients with CY1 and/or P1a.

METHODS

We retrospectively reviewed GC patients diagnosed with CY1 and/or P1a at 34 institutions in Japan between 2008 and 2012. Selection criteria were: adenocarcinoma, no distant metastasis except CY1 or P1a, and no prior treatment. The subjects were divided into an Initial-Chemotherapy group and an Initial-Surgery group, according to the initial treatment.

RESULTS

A total of 824 patients were collected and 713 eligible patients were identified for this study. As the initial treatment, 150 patients received chemotherapy (Initial-Cx), and 563 patients underwent surgery (Initial-Sx). Initial-Cx regimens were cisplatin plus S1/docetaxel plus cisplatin plus S1/others (n = 90/37/23). Both overall survival (OS) and progression-free survival (PFS) were similar between the Initial-Cx and Initial-Sx groups (median OS 24.8 and 24.0 months, HR 1.07, 95% CI 0.87-1.3; median PFS 14.9 and 13.9 months, HR 1.04, 95% CI 0.85-1.27). The 5-year OS rates were 22.3% in the Initial-Cx group and 21.5% in the Initial-Sx group.

CONCLUSIONS

Although, the preoperative chemotherapy did not show a survival benefit for GC patients with CY1 and/or P1a, initial-Cx showed favorable survival in patients who converted to P0 and CY0.

Extended intraoperative peritoneal lavage as prophylactic peritoneal recurrence for locally advanced gastric cancer: a prospective randomized trial

BACKGROUND

To demonstrate whether extensive intraoperative peritoneal lavage (EIPL) could yield better results in overall survival and less recurrence, regardless of peritoneal cytology, compared to standard peritoneal lavage (SPL).

METHODS

A prospective randomised multicenter study including 94 patients (47 per arm) to detect a 20% difference in 3-year overall survival in patients with locally advanced tumours without peritoneal carcinomatosis. Three samples of peritoneal fluid were obtained (at the beginning, the end of procedure and after the assigned peritoneal lavage). Clinicopathological and surgical data were analysed by group. Postoperative complications, location of recurrence and surgical approach were evaluated. Overall survival was calculated by the Kaplan-Meier method and the uni/multivariate analysis for prognostic factors was carried out using Cox regression analysis.

RESULTS

A total of 86 patients were analysed (4 excluded per group). No statistical differences were observed in clinicopathological or surgical data between groups, considering both groups well-balanced for analysis. Overall survival at 3 years was 64.3% for SPL vs. 62.3% for EIPL (p 0.421). Only three patients had at least one positive peritoneal cytology (1:2). There were no differences regarding postoperative complications (SPL: 37.2% vs. EIPL: 32.5%, p 0.65) or between location of recurrence and number of recurrences. The number of recurrences did not differ between surgical approaches, but locoregional and peritoneal recurrences were fewer with the laparoscopic approach (p 0.048).

CONCLUSIONS

The regular use of extensive peritoneal lavage in patients with locally advanced gastric cancer, regardless of peritoneal cytology, has not been effective as prophylaxis of peritoneal recurrence or better survival.

Impact of metabolism-related mutations on the heart rate of gastric cancer patients after peritoneal lavage

BACKGROUND

During surgery for gastric cancer, peritoneal lavage using warm distilled water can cause temporary hemodynamic changes.

AIM

To examine the associations between changes in heart rate and single nucleotide polymorphisms (SNPs).

METHODS

This was a prospective observational study of patients with gastric cancer who underwent gastrectomy and peritoneal hypotonic lavage at the Third Affiliated Hospital of Soochow University from March 2018 to March 2019. Related SNPs were selected, and the verified exons were analyzed. Heart rate and blood pressure (BP) were measured before and after lavage. The patients were grouped as heart rate change ≥ 30% vs < 30%. Comparison and regression analyses of the selected SNPs were performed between the two groups.

RESULTS

According to the inclusion/exclusion criteria, 194 patients were included in the analysis. Of these patients, 138 were male, with a mean age of 65.9 ± 0.8 years, and 56 were female, with a mean age of 65.0 ± 1.3 years. Heart rate dropped by 0%-10% in 65 participants, by 10%-15% in 29, by 15%-20% in 23, by 20%-50% in 39, by 50%-100% in four, six had a cardiac arrest, and 28 had an increase in heart rate. Considering the possible impact of exonic SNPs on the phenotypes, TEP1 (rs938886), TEP1 (rs1713449), and RECQL5 (rs820196) were analyzed. The haplotype analysis suggested that the haplotypes CTT [odds ratio (OR) = 2.018, 95% confidence interval (CI): 1.012-4.025, P = 0.0430] and GCC (OR = 2.293, 95%CI: 1.174-4.477, P = 0.0131) of TEP1 (rs938886), TEP1 (rs1713449), and RECQL5 (rs820196) increased the risk of a drop in heart rate > 30%.

CONCLUSION

The TEP1 (rs938886), TEP1 (rs1713449), and RECQL5 (rs820196) SNPs were associated with changes in heart rate ≥ 30% during intraperitoneal lavage using distilled water after gastrectomy for gastric cancer.

Peritoneal Lavage Cytology Following Neoadjuvant Chemotherapy for Gastric Adenocarcinoma: Low Yield in Detecting Peritoneal Metastases

BACKGROUND

Peritoneal lavage cytology (PLC) can detect advanced disease in gastric adenocarcinoma (GC); however, routine practice remains controversial. Furthermore, the effect of neoadjuvant chemotherapy (NAC) on cytological detection of carcinomatosis is unknown.

METHODS

Using a 2012-2020 prospective database, we retrospectively reviewed patients with GC who underwent NAC followed by a staging laparoscopic peritoneal lavage with or without biopsy of suspicious peritoneal nodules. PLC results were considered discordant if they did not align with the peritoneal biopsy results. Patients with benign peritoneal cytology (Cyt-) or biopsy results who had postoperative time to carcinomatosis of <6 months were considered to have diagnostic failure of peritoneal lavage.

RESULTS

Fifty-five patients with GC who underwent NAC followed by staging diagnostic laparoscopy with peritoneal lavage were identified. The majority of the patients in the cohort had Cyt- lavage (89.1%). Of the patients who underwent resection, 76.1% had T3 or greater disease on final pathology and 66% had nodal metastases. In 23 patients (41.8%) who had both peritoneal lavage and biopsy, four cases (17.4%) had discordant results. Diagnostic failure rate was 20% at 6 months and 42.2% at 12 months. The median time to carcinomatosis in patients who were Cyt- or biopsy negative was 7.9 months.

CONCLUSION

PLC after NAC has a high diagnostic failure rate and inaccurately predicts carcinomatosis in 20% of patients with GC. Novel methods for identifying cytology positive GC after NAC should also be developed and evaluated, since the risk of peritoneal dissemination is high.

Effects of differential distributed-JUP on the malignancy of gastric cancer

JUP, a homologue of β-catenin, is a cell-cell junction protein involved in adhesion junction and desmosome composition. JUP may have a controversial role in different malignancies dependence of its competence with or collaboration with β-catenin as a transcription factor. In this study, we reveal that the function of JUP is related to its cellular location in GC development process from epithelium-like, low malignant GC to advanced EMT-phenotypic GC. Gradual loss of membrane and/or cytoplasm JUP is closely correlated with GC malignancy and poor prognostics. Knockdown of JUP in epithelium-like GC cells causes EMT and promotes GC cell migration and invasion. Ectopic expression of wild JUP in malignant GC cells leads to an attenuated malignant phenotype such as reduced cell invasive potential. In mechanism, loss of membrane and/or cytoplasm JUP abolishes the restrain of JUP to EGFR at cell membrane and results in increased p-AKT levels and AKT/GSK3β/β-catenin signaling activity. In addition, nuclear JUP interacts with nuclear β-catenin and TCF4 and plays a synergistic role with β-catenin in promoting TCF4 transcription and its downstream target MMP7 expression to fuel GC cell invasion.

Reduced expression of exosomal miR‑29s in peritoneal fluid is a useful predictor of peritoneal recurrence after curative resection of gastric cancer with serosal involvement

The peritoneal surface is the most frequent site of metastasis disease in patients with gastric cancer. Even after curative surgery and adjuvant chemotherapy, peritoneal recurrences often develop. Exosomes play pivotal roles in tumor metastasis via the transfer of microRNAs (miRNAs). In the present study, exosomes were isolated from peritoneal lavage fluid or ascites in 85 patients with gastric cancer and the relative expression levels of miR-29s were examined. The expression of miR-29a-3p, miR-29b-3p and miR-29c-3p in peritoneal exosomes were all downregulated in patients with peritoneal metastases (PM) compared to those without PM. In 30 patients who underwent curative gastrectomy with serosa-involved (T4) gastric cancer, 6 patients exhibited recurrence in the peritoneum within 12 months. The expression levels of miR-29s at gastrectomy tended to be lower in these 6 patients than in the other 24 patients with significant differences in miR-29b-3p (P=0.003). When the patients were divided into two groups based on median levels of miR-29s, peritoneal recurrence developed more frequently in patients with low expression of miR-29b-3p, and lower expression of miR-29s were related with worse overall survival. miR-29s are thought to play a suppressive role in the growth of disseminated peritoneal tumor cells. Reduced expression of miR-29b in peritoneal exosomes is a strong risk factor of developing postoperative peritoneal recurrence.

Efficacy of Postoperative Chemotherapy After Resection that Leaves No Macroscopically Visible Disease of Gastric Cancer with Positive Peritoneal Lavage Cytology (CY1) or Localized Peritoneum Metastasis (P1a): A Multicenter Retrospective Study

BACKGROUND

Gastric cancer (GC) patients with positive peritoneal lavage cytology (CY1) and/or localized peritoneum metastasis (P1a) are defined as stage IV in the 15th edition of the Japanese Classification of Gastric Cancer. In Japan, the most common treatment for patients with CY1 and/or P1a is gastrectomy followed by postoperative chemotherapy.

PATIENTS AND METHODS

Subjects in this multi-institutional retrospective study were GC patients with CY1 and/or P1a who received surgical resection that leaves no macroscopically visible disease. Patients were selected from 34 institutions in Japan between 2007 and 2012. Selection criteria included adenocarcinoma, no distant metastasis except CY1 and P1a, and no prior treatment for GC before surgery.

RESULTS

Among 824 patients registered, 506 were identified as eligible, with a background of P0CY1, P1aCY0, or P1aCY1 (72.5%, 16.0%, and 11.5% of subjects, respectively). Sixty-two patients had not received postoperative chemotherapy (no-Cx), whereas 444 patients had received postoperative chemotherapy: S-1 monotherapy (S-1; n = 267, 52.7%), cisplatin plus S-1 (CS; n = 114, 22.5%), and others (n = 63, 12.6%). Overall survival (OS) was 29.5, 24.7, 25.4 and 9.9 months in the S-1, CS, 'others', and no-Cx groups, respectively [CS vs. S-1: hazard ratio (HR) 1.15, 95% confidence interval (CI) 0.89-1.50; p = 0.275]. In multivariate analysis, OS was similar between the S-1 and CS groups (CS vs. S-1: HR 1.19, 95% CI 0.92-1.55; p = 0.18).

CONCLUSIONS

Postoperative chemotherapy after gastrectomy that leaves no macroscopically visible disease may have some survival benefits for GC patients with CY1 and/or P1a. In contrast, S-1 plus cisplatin seems to have no additional benefit over S-1 treatment alone.

Surgical treatment of gastric carcinoma with ovarian metastases

Ovarian metastases from extragenital neoplasms are rare. The prevalent sites of the primary tumors were the breast, colorectum and the stomach. The Krukenberg tumor (KT) is defined as a gastrointestinal cancer which metastasized to the ovaries. Metastasis to the ovary may appear at the time of diagnosis of the primary tumor (synchronous) or during observation (metachronous). Common clinical presentations are abdominal distention, pain, palpable mass, bloating, ascites or pain during sexual intercourse. Diagnosis can be made by ultrasound examinations, CT or EMR scans, laparotomy and/or a biopsy of the ovary. The current standard treatment for patients with metastatic gastric cancer is systemic chemotherapy, however, treatment strategy for KTs from gastric cancer has not been clearly established and surgical treatment is considered mainly for metachronous tumors. The prognosis of patients with ovarian metastasis of gastric cancer origin is poorer compared with that of other primary tumors. Although the results of cytoreductive surgery – especially in combination with modern chemotherapy – seems to be promising, the optimal therapeutic strategies for such patients requires further prospective studies.

Treatment of peritoneal metastases from gastric carcinoma

Patients with advanced gastric cancer and positive peritoneal cytology and/or peritoneal dissemination are deemed to be incurable and to hold dismal prognosis. So far, the only treatment option for these patients has been palliative systemic (chemo)therapy. However, for the last three decades, great progress has been made in attempts to treat (potential) peritoneal dissemination by means of complete cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) after preoperative systemic therapy. This review is focused on the recent achievements of this multimodal strategy. Additionally, the review stands as background for the 4th International Conference “Advances in Surgical Oncology” that was held at the Medical University of Lublin (Poland) in November 2017, and dedicated to cytoreductive surgery and HIPEC for advanced gastric cancer.

Intraoperative peritoneal lavage cytology offers prognostic significance for gastric cancer patients with curative resection

Outcomes of patients with gastric cancer who exhibit positive peritoneal lavage cytology findings (CY⁺ ) vary by diagnostic methods because of quantitative and qualitative cancer cell diversity. This study sought to establish practical diagnostic criteria for performing curative resections, based on peritoneal lavage cytology findings in gastric cancer patients. We enrolled 1028 patients with gastric cancer who underwent R0/1 (n = 911) or R2 (n = 117) resections and analyzed relationships between cancer cell findings in peritoneal lavage fluid and clinicopathological factors in the R0/1 group. We found 68 patients with CY⁺ status. Receiver operating characteristic analyses and multivariate analyses showed that the presence of ≥1 signet ring cell, ≥5 cell clusters or ≥50 isolated cancer cells in peritoneal lavage fluid predicted poor prognoses in the 68 CY⁺ patients. High-risk CY⁺ group patients with at least one of the above predictors had the highest hazard ratio (HR = 3.28, P < 0.001). The remaining (low-risk) patients had a survival curve similar to that of patients with a normal cytology. The high-risk CY⁺ patients who underwent R1 resection had poor prognoses despite no macroscopic peritoneal metastasis (2% 5-year survival)-equivalent to that of patients who underwent R2 resection. The CY⁺ criteria defined in this study could help identify candidates for curative resection as an initial therapy for gastric cancer.

Regional but fatal: Intraperitoneal metastasis in gastric cancer

Peritoneal carcinomatosis appears to be the most common pattern of metastasis or recurrence and is associated with poor prognosis in gastric cancer patients. Many efforts have been made to improve the survival in patients with peritoneal metastasis. Hyperthermic intraperitoneal chemotherapy remains a widely accepted strategy in the treatment of peritoneal dissemination. Several phase II-III studies confirmed that the combined cytoreducitve surgery and hyperthermic intraperitoneal chemotherapy resulted in longer survival in patients with peritoneal carcinomatosis. In addition, proper selection and effective regional treatment in patients with high risk of peritoneal recurrence after resection will further improve prognosis in local advanced gastric cancer patients.

Prognostic significance of CEA expression by RT-PCR in peritoneal wash from patients with gastric cancer: result of a 5-year follow-up after curative resection

OBJECTIVE

Peritoneal recurrence is the most common cause of death after surgery for gastric cancer. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis has been used to detect free cancer cells in peritoneal wash during surgery. This study was conducted to evaluate the prognostic significance of carcinoembrionic antigen (CEA) mRNA detected by RT-PCR in peritoneal wash from patients with gastric cancer after curative resection through a 5-year follow-up.

MATERIALS AND METHODS

Peritoneal wash were obtained from 117 patients who underwent curative surgery for gastric cancer. The association between the CEA RT-PCR results, clinicopathological factors, and factors affecting gastric cancer recurrence were evaluated.

RESULTS

Among the 117 cases, 38 (32.5%) revealed positive CEA expression. Patients with positive CEA expression showed a higher rate of peritoneal recurrence than those with negative CEA expression (p = 0.047). Depth of invasion, lymph node metastasis, TNM stage, and CEA expression were factors affecting recurrence. CEA expression and depth of invasion were significant prognostic factors in a multivariate analysis, and CEA expression was the most important prognostic factor for recurrence in patients who had undergone curative resection for gastric cancer (hazard ratio: 2.747, p = 0.046).

CONCLUSIONS

CEA expression in the peritoneal wash was significantly associated with peritoneal recurrence and was the most important prognostic factor for gastric cancer recurrence after curative resection.

Role of genetic detection in peritoneal washes with gastric carcinoma: The past, present and future

The most frequent cause of treatment failure following surgery for gastric cancer is peritoneal dissemination, mainly caused by the seeding of free cancer cells from the primary gastric cancer, which is the most common type of spread. Unfortunately, there is no standard modality of intraperitoneal free cancer cells detection to predict peritoneal metastasis until now. We reviewed English literature in PubMed was done using the MeSH terms for gastric cancer, peritoneal wash, and reverse transcriptase polymerase chain reaction. All the articles were reviewed and core information was tabulated for reference. After a comprehensive review of all articles, the data was evaluated by clinical implication and predictive value of each marker for peritoneal recurrence. There are still many limitations to overcome before the genetic diagnosis for free cancer cells detection can be considered as routine assay. To make it a reliable diagnostic tool for detecting free cancer cells, the process and method of genetic detection with peritoneal washes should be standardized, and the development of simple diagnostic devices and easily available kits are necessary. Herein, we reviewed the past, present and future perspectives of the peritoneal lavage for the detection of intraperitoneal free cancer cells in patients with 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 significance of peritoneal lavage cytology at three cavities in patients with gastric cancer

BACKGROUND

We sought to determine the prognostic significance of intraoperative peritoneal lavage cytology (CY) at 3 different abdominal cavities and establish the optimal treatment for gastric cancer patients with positive peritoneal cytology (CY1).

METHODS

A total of 1,039 patients with primary gastric adenocarcinoma who underwent CY at 3 cavities (Douglas' pouch, left subphrenic cavity, and right subhepatic cavity) were enrolled; 116 (11%) patients had at least one positive cavity. We retrospectively analyzed the clinicopathologic characteristics and survival of these 116 patients with CY1.

RESULTS

Seventeen (15%) of the patients had negative cytology at Douglas' pouch but positive cytology at one or both of the other cavities. The 116 patients' overall 2-year survival rate was 22.9%, with the median survival time of 11 months. The overall 2-year survival rates for the patients with positive cytology at 1, 2, and 3 cavities were 41.9%, 35.8%, and 15%, with median survival times of 17, 18, and 9 months, respectively (P < .01). A multivariate analysis revealed that macroscopic type 4 tumor, R2 resection, lymph node metastasis, and postoperative chemotherapy were independent prognostic factors. Among the CY1 patients with type 4 tumors, there was no substantial difference in survival between the patients who underwent R1 or R2 resection, although the statistical power of this subgroup analysis was low.

CONCLUSION

CY at 3 cavities might be a useful method to decrease the false-negative rate. Palliative gastrectomy for CY1 patients with type 4 tumors is still controversial.

Molecular diagnosis and therapy for occult peritoneal metastasis in gastric cancer patients

To apply an individualized oncological approach to gastric cancer patients, the accurate diagnosis of disease entities is required. Peritoneal metastasis is the most frequent mode of metastasis in gastric cancer, and the tumor-node-metastasis classification includes cytological detection of intraperitoneal cancer cells as part of the staging process, denoting metastatic disease. The accuracy of cytological diagnosis leaves room for improvement; therefore, highly sensitive molecular diagnostics, such as an enzyme immunoassay, reverse transcription polymerase chain reaction, and virus-guided imaging, have been developed to detect minute cancer cells in the peritoneal cavity. Molecular targeting therapy has also been spun off from basic research in the past decade. Although conventional cytology is still the mainstay, novel approaches could serve as practical complementary diagnostics to cytology in near future.

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.

Circulating methylated MINT2 promoter DNA is a potential poor prognostic factor in gastric cancer

BACKGROUND AND AIM

Aberrant DNA methylation has been shown to be associated with the growth, development, metastasis, and prognosis of tumors. Methylated DNAs may be suitable biomarkers for cancer patients. Here, we investigated whether circulating methylated MINT2 DNAs represent a potential poor prognostic factor in gastric cancer (GC).

METHODS

MINT2 methylation was detected by real-time methylation-specific PCR in tumor tissues, pairing preoperative peritoneal lavage fluid (PPLF) and blood from 92 GC patients. The theory meaning and clinical practicality value of MINT2 methylation in different specimens were analyzed.

RESULTS

The methylation status of the MINT2 gene was found to be significantly higher in tumor tissues (44.6%, 41/92) than in adjacent normal tissues (3.3%, 3/92). No MINT2 methylation was found in healthy controls, and partial MINT2 methylation was observed in three (6.25%, 3/48) patients with chronic atrophic gastritis. The frequency of MINT2 methylation in pairing PPLF and blood samples from 92 GC patients was 40.2% (37/92) and 39.1% (36/92), respectively. Methylated MINT2 in tumor tissues, pairing PPLF, and blood samples were very approximate. Aberrant MINT2 methylation in tumor tissues and pairing PPLF or blood samples were closely related to peritoneal dissemination, tumor progression, and poor prognosis (all P < 0.0001).

CONCLUSIONS

Aberrant MINT2 methylation in PPLF/blood may predict peritoneal micrometastasis for GC patients, which is a potential poor prognostic factor in GC.

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.

Clinical significance of carcinoembryonic antigen in peritoneal lavage from patients with gastric cancer

BACKGROUND

Peritoneal carcinomatosis is the most common pattern of recurrence of gastric cancer, and it is important to identify patients at high risk for recurrence. Although the carcinoembryonic antigen level in peritoneal lavage (pCEA) was reported to be a useful biomarker to predict peritoneal recurrence in a small series, its clinical significance has not been fully validated. We evaluated the clinical significance of pCEA in a large cohort of patients with gastric cancer.

METHODS

We prospectively analyzed the pCEA level in 597 patients with histologically proven gastric cancer who underwent laparotomy.

RESULTS

A significant relationship was demonstrated between the value of pCEA and clinicopathologic features, such as the peritoneal lavage cytology, peritoneal metastasis, the depth of tumor invasion, and the lymph node metastasis. The cutoff value was set at 100 ng/g of protein, and 134 of the 462 patients who underwent curative surgery had positive pCEA findings. The overall and the intraperitoneal-recurrence-related survival of patients positive for pCEA were significantly poorer than those of pCEA-negative patients. When we analyzed the patients with pathologic stage I through III gastric cancers separately, the pCEA-positive patients had poorer prognoses than the pCEA-negative patients who had stage III gastric cancer. In a univariate analysis, the tumor size, depth of tumor invasion, lymph node metastasis, histologic type, serum CEA (sCEA), and pCEA were found to affect the patients' outcomes, although a multivariate analysis found only the extent of lymph node metastasis to be an independent prognostic factor.

CONCLUSION

The pCEA level is a useful biomarker to predict gastric cancer-related death. Moreover, the pCEA level may be useful to identify a cohort of patients with gastric cancer who need more intensive adjuvant chemotherapy to improve their prognoses.

Cell-cell and cell-matrix dynamics in intraperitoneal cancer metastasis

The peritoneal metastatic route of cancer dissemination is shared by cancers of the ovary and gastrointestinal tract. Once initiated, peritoneal metastasis typically proceeds rapidly in a feed-forward manner. Several factors contribute to this efficient progression. In peritoneal metastasis, cancer cells exfoliate into the peritoneal fluid and spread locally, transported by peritoneal fluid. Inflammatory cytokines released by tumor and immune cells compromise the protective, anti-adhesive mesothelial cell layer that lines the peritoneal cavity, exposing the underlying extracellular matrix to which cancer cells readily attach. The peritoneum is further rendered receptive to metastatic implantation and growth by myofibroblastic cell behaviors also stimulated by inflammatory cytokines. Individual cancer cells suspended in peritoneal fluid can aggregate to form multicellular spheroids. This cellular arrangement imparts resistance to anoikis, apoptosis, and chemotherapeutics. Emerging evidence indicates that compact spheroid formation is preferentially accomplished by cancer cells with high invasive capacity and contractile behaviors. This review focuses on the pathological alterations to the peritoneum and the properties of cancer cells that in combination drive peritoneal metastasis.

Accurate and rapid novel genetic diagnosis for detection of sentinel lymph node metastasis in breast cancer patients

Background:

The transcription-reverse transcription concerted reaction (TRC) test is a novel molecular-based procedure, which can assess nodal metastasis accurately and quickly. We examined the usefulness of the TRC test with a double marker, cytokeratin 19 (CK19) and carcinoembryonic antigen (CEA) mRNA, to detect sentinel lymph nodes (SLN) metastasis in breast cancer patients.

Methods:

A total of 264 SLNs from 131 breast cancer patients were assigned to a training set (109 SLNs from 50 patients) and validation set (155 SLNs from 81 patients). Cytokeratin 19 and CEA mRNA were detected by TRC tests, and the sensitivity and specificity of the SLN metastasis between the TRC and histology cohorts were compared.

Results:

Mean copy numbers of CK19 and CEA by TRC tests were increased according to the metastatic size. In the training set, TRC test showed 100% sensitivity, specificity and concordance rates against the permanent histopathology test. In the validation set, sensitivity was 97.1%, specificity was 99.2% and the concordance rate was 99.4%.

Conclusion:

Our results showed that the detection of CK19 and CEA mRNA using the TRC test is, an accurate and rapid method for detection of SLN metastasis and can be applied as an intraoperative molecular diagnosis in breast cancer patients.

Role of vascular endothelial growth factor (VEGF) and VEGF-R genotyping in guiding the metastatic process in pT4a resected gastric cancer patients

In radically resected gastric cancer the possibility to predict the site of relapse could be clinically relevant for the selection of post-surgical management. We previously showed that specific tumour integrins genotypes are independently associated with either peritoneal or hematogenous metastases (ITGA and ITGV). Recently VEGF and VEGF-R polymorphisms have been demonstrated to potentially affect tumour angiogenesis and the metastatic process in gastric cancer. We then investigated the role of VEGFs and VEGF-R genotyping in determining either peritoneal carcinosis or hematogenous metastases in radically resected gastric cancer patients. Tumour genotyping for integrins (ITGA and ITGV) was also performed according to our previous findings. Genotyping for VEGF-A, VEGF-C, VEGFR-1,2,3 and ITGA and ITGV was carried out on pT4a radically resected gastric tumours recurring with either peritoneal-only carcinosis or hematogenous metastases. 101 patients fulfilled the inclusion criteria: 57 with peritoneal carcinomatosis only and 44 with hematogenous spread only. At multivariate analysis, intestinal histology and the AC genotype of rs699947 (VEGFA) showed to independently correlate with hematogenous metastases (p = 0.0008 and 0.008 respectively), whereas diffuse histology and the AA genotype of rs2269772 (ITGA) independently correlated with peritoneal-only diffusion (p = <0.0001 and 0.03 respectively). Our results seem to indicate that combining information from genotyping of rs699947 (VEGFA, AC), rs2269772 (ITGA, AA) and tumour histology could allow clinicians to individuate gastric cancer at high risk for recurrence either with peritoneal or hematogenous metastases. The selection tool deriving from this analysis may allow an optimal use of the available treatment strategies in these patients.

Knockdown of hypoxia-inducible factor-1α accelerates peritoneal dissemination via the upregulation of MMP-1 expression in gastric cancer cell lines

This study was performed to clarify the role of hypoxia-inducible factor-1 α (HIF-1α) in the development of peritoneal dissemination in a xenograft mouse model of gastric cancer. HIF-1α knockdown (KD) and control (SC) gastric cancer cells, which were established using the MKN45 and MKN74 cell lines, were studied. The two paired cell lines were directly inoculated into the peritoneal cavity of nude mice. The number and the weight of disseminated nodules were compared between tumors generated from the KD and SC cells. In addition, the molecular mechanism was addressed through analysis of the expression levels of metastasis-related genes. The MKN45-KD cell line demonstrated significantly greater numbers of disseminated nodules and formed a larger tumor mass than the MKN45-SC cell line (p<0.05). MKN74-KD cells also tended to induce a greater number of nodules and to produce those with a heavier weight than the SC cells. An in vitro adhesion assay revealed differing results regarding the adhesion activity to extracellular matrix and monolayer mesothelium cells of the gastric cancer cells derived from the various parental cells. However, the expression of MMP-1 mRNA in the disseminated nodules was significantly increased in the KD cells compared to the SC cells derived from the two parental cell lines (p<0.01). An immunohisto-chemical study further demonstrated that there was stronger staining for MMP-1 in the MKN74-KD in comparison to MKN74-SC cells. Loss of HIF-1α may contribute to the development of aggressive peritoneal dissemination via the upregulation of MMP-1 in gastric cancer cells.

Rt-PCR increases detection of submicroscopic peritoneal metastases in gastric cancer and has prognostic significance

BACKGROUND

Positive peritoneal cytology confers the same prognosis as clinical stage IV disease in gastric cancer. Conventional cytology examination, however, has low sensitivity. We hypothesize that real-time polymerase chain reaction (RT-PCR) may have increased sensitivity and provide more accurate staging information.

METHODS

From February 2007 to April 2009, peritoneal lavage samples were collected prospectively from 156 patients with biopsy-proven gastric cancer undergoing staging laparoscopy. These washings were analyzed by both Papanicolaou staining and RT-PCR for the tumor marker carcinoembryonic antigen (CEA).

RESULTS

Visible peritoneal disease was seen at laparoscopy in 38 patients (LAP+, 24%). Cytology was positive (CYT+) in 23 patients, while RT-PCR was positive (PCR+) in 30. The sensitivity of CYT for the detection of visible disease was 61% compared to 79% for PCR (P = 0.02). No visible peritoneal disease was seen at laparoscopy (LAP-) in 118 (76%) patients. Eight (7%) were CYT+, while 28 (24%) were PCR+. Predictors of PCR positivity included advanced-stage disease (T3-4 vs. T1-2 tumors) and poor pathologic features such as vascular or perineural invasion. Long-term follow-up demonstrated a worse survival of LAP-CYT-PCR+ (P = 0.0003) and LAP-CYT+PCR+ (P = 0.0004) compared to LAP-CYT-PCR- patients. There was no significant difference in survival between CYT-PCR+ and CYT+PCR+ patients. PCR positivity also predicted a higher likelihood of disease recurrence after resection. An R0 resection was performed in 85 LAP- patients (54%): only 1 (1%) was CYT+, while 13 (15%) were PCR+. Of this group, PCR+ demonstrated a worse survival than PCR- patients (P = 0.02). Further analysis showed that, in R0 resection, stage III/IV, CYT- subgroup, PCR+ was associated with a trend towards worse survival (P = 0.09) compared to PCR- patients.

CONCLUSION

RT-PCR for CEA increases the detection of subclinical peritoneal disease and is more sensitive than cytology. Predictors of positive PCR included advanced-stage disease, vascular invasion, and perineural invasion. PCR positivity was associated with increased disease recurrence and decreased survival. Further follow-up is required to determine if PCR positivity alone is an independent predictor of poor survival in gastric cancer.

Gastric cancer cell supernatant causes apoptosis and fibrosis in the peritoneal tissues and results in an environment favorable to peritoneal metastases, in vitro and in vivo

Background

In this study, we examined effects of soluble factors released by gastric cancer cells on peritoneal mesothelial cells in vitro and in vivo.

Methods

HMrSV5, a human peritoneal mesothelial cell line, was incubated with supernatants from gastric cancer cells. Morphological changes of HMrSV5 cells were observed. Apoptosis of HMrSV5 cells was observed under a transmission electron microscope and quantitatively determined by MTT assay and flow cytometry. Expressions of apoptosis-related proteins (caspase-3, caspase-8, Bax, bcl-2) were immunochemically evaluated.

Results

Conspicuous morphological changes indicating apoptosis were observed in HMrSV5 cells 24 h after treatment with the supernatants of gastric cancer cells. In vivo, peritoneal tissues treated with gastric cancer cell supernatant were substantially thickened and contained extensive fibrosis.

Conclusions

These findings demonstrate that supernatants of gastric cancer cells can induce apoptosis and fibrosis in HMrSV5 human peritoneal mesothelial cells through supernatants in the early peritoneal metastasis, in a time-dependent manner, and indicate that soluble factors in the peritoneal cavity affect the morphology and function of mesothelial cells so that the resulting environment can become favorable to peritoneal metastases.

Risk factors for peritoneal recurrence in stage II/III gastric cancer patients who received S-1 adjuvant chemotherapy after D2 gastrectomy

BACKGROUND

The peritoneum is still the most frequent site of recurrence in stage II/III gastric cancer patients, although the survival rate was improved by the introduction of S-1 adjuvant chemotherapy. The objective of this retrospective study was to clarify the risk factors for peritoneal recurrence in patients who received S-1 adjuvant chemotherapy.

METHODS

Peritoneal recurrence-free survival was examined in 100 gastric cancer patients who underwent curative D2 surgery, which were diagnosed with stage II or III disease pathologically, and received adjuvant S-1 between June 2002 and March 2011. The univariate and multivariate analyses were performed to identify risk factors by a Cox proportional hazards analysis.

RESULTS

The P-RFS was 64.3% at 3 years and 58.8% at 5 years. A total of 18 patients were diagnosed with peritoneal recurrence. The macroscopic tumor diameter, depth of tumor invasion, and lymph node metastasis were the significant factors identified by the univariate analysis, while the tumor diameter and lymph node metastasis were the only significant independent risk factors identified by the multivariate analysis.

CONCLUSIONS

The macroscopic tumor diameter and presence of lymph node metastasis were the most important risk factors for peritoneal recurrence. When patients had these risk factors, S-1 was not sufficient to inhibit peritoneal recurrence. A novel adjuvant chemotherapeutic agent targeting peritoneal metastasis in these patients should be developed.

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.

Aberrant gene methylation is a biomarker for the detection of cancer cells in peritoneal wash samples from advanced gastric cancer patients

PURPOSE

To assess whether gene methylation in peritoneal fluid (PF) is clinically feasible for determining micrometastasis to the peritoneum in gastric cancer.

METHODS

The gene methylation of BNIP3, CHFR, CYP1B1, MINT25, SFRP2, and RASSF2 were analyzed in 107 specimens of PF by quantitative methylation-specific polymerase chain reaction. All patients were placed into one of 3 groups: group A (n = 42), patients with depth of cancer invasion at muscularis propria (MP) or less than MP; group B (n = 45), depth of cancer invasion beyond the MP; and group C (n = 20), histologically diagnosed peritoneal metastasis or cancer cells cytologically defined in the peritoneal cavity. Patients in both groups A and B were diagnosed as having no cancer cells by peritoneal cytology and histology.

RESULTS

The methylation status of the 6 genes was found to be significantly different among the 3 groups (group A, 0-5%; group B, 0-15%; group C, 15-45%; P < 0.01). Furthermore, the rate of positive methylation in any of the 6 genes was significantly different in each group (group A, 7%; group B, 20%; group C, 75%; P < 0.001). Three of 9 patients in group B with positive methylation in any of 6 genes experienced peritoneal recurrence. On the other hand, only 1 of 36 patients without gene methylation experienced peritoneal recurrence (P < 0.05).

CONCLUSIONS

DNA methylation in PFs is a possible marker detecting occult neoplastic cells on the peritoneum. Methylation analysis along with a cytological examination might therefore improve the positive detection of cancer cells in PF of gastric cancer.

Interaction of coagulation factors and tumor-associated macrophages mediates migration and invasion of gastric cancer

Abundant macrophage infiltration and increased expression of coagulation factors have been observed in cancer patients. The aim of the present study was to determine how the interaction between activated coagulation factors and monocytes/macrophages contributes to gastric cancer (GC) cell migration and invasion. We assessed cytokine/chemokine production of coagulation-factor-treated macrophages by ELISA. The effects of the interaction between coagulation factors and tumor-associated macrophages (TAM) on GC cell migration and invasion were determined by in vitro migration and invasion assay. In addition, we used an in vitro co-culture system of GC cells/TAM treated by coagulation factors to evaluate the effect of coagulation factor/TAM interaction on the human umbilical vein endothelial cell line (HUVEC). We found that the M2-like phenotype of interleukin (IL)-4(high), IL-10(high), transforming growth factor (TGF)-β(high), tumor necrosis factor (TNF)-α(high) was exhibited when the human monocytic cell line THP-1 was stimulated by coagulation factors III (TF), VIIa (FVIIa) and XIIa (FXIIa). For the migration assay, the GC cells (BGC-823 or SGC-7901) that were co-cultured with activated coagulation factor/TAM both showed increased migration. For the invasion assay, both BGC-823 and SGC-7901 cells co-cultured with TF/TAM showed increased invasion. We also found that TAM activated by coagulation factors could induce vascular endothelial growth factor/MMP-9 expression, which could promote invasion of GC cells. The HUVEC co-cultured with TAM (PMA-treated THP-1 macrophages co-cultured with GC cells) expressed high levels of FXIIa. In conclusion, coagulation factors might facilitate GC cell migration and invasion by transforming macrophages toward TAM-like cells. Interaction of coagulation factors and TAM mediates migration and invasion of GC.

Prognostic significance of MAGE in peritoneal washes in gastric carcinoma patients without peritoneal metastasis: results of a 5-year follow-up study

GOALS

The RT-PCR assay of peritoneal washes has been used to predict peritoneal metastasis of gastric carcinoma. We used melanoma associated gene (MAGE) RT-PCR to detect peritoneal metastasis of gastric carcinoma after curative surgery and evaluated its clinical significance.

METHOD

Eighty-four peritoneal washes and 23 tumor and normal tissues were obtained from 84 gastric carcinoma patients. MAGE A1-A6 RT-PCR was carried out, and the results were evaluated according to their clinicopathologic characteristics. Five-year follow-up clinical studies were carried out periodically, and overall survival rates were retrospectively investigated using medical records.

RESULTS

For the paired tumor and normal tissues, MAGE expression rates were 65.2% and 4.3%, respectively. In peritoneal fluids, 11 cases (13.1%) revealed MAGE expression, and higher MAGE expression rates were observed with young age, deeper invasion, and advanced stages of tumor groups. MAGE-positive cases had much higher recurrence rates than MAGE-negative cases (45.5% vs. 9.6%, P<0.002). Among T-stage, N-stage, and MAGE expression; MAGE expression was determined to be the most important prognostic factor for overall survival rate by Cox proportional hazard model analysis.

CONCLUSION

MAGE RT-PCR results for peritoneal fluid disclosed significant associations with peritoneal recurrence of gastric carcinoma and proved to be the most important factor for overall survival rate in gastric carcinoma patients who had undergone radical resection.

Allele polymorphisms of tumor integrins correlate with peritoneal carcinosis capability of gastric cancer cells in radically resected patients

BACKGROUND

Preclinical studies suggested that integrins are relevant for gastric cancer diffusion. We investigated integrins polymorphisms role in determining peritoneal carcinosis or hematogenous metastases in radically resected gastric cancer.

PATIENTS AND METHODS

Integrins genotyping was carried out on pT3 radically resected gastric tumors recurring with either peritoneal-only carcinosis or hematogenous metastases.

RESULTS

The following factors resulted independently associated with peritoneal carcinosis or hematogenous metastases: the A genotype of rs2269772 (ITGA3) [odds ratio (OR) for peritoneal carcinosis: 22.2, 95% confidence interval 1.2-40, P=0.03], the G genotype of rs2269772 (ITGA3) (OR for hematogenous metastases: 5.5, 95% confidence interval 2.2-14.15, P=0.0003), the C genotype of rs11902171 (ITGV) (OR for peritoneal carcinosis: 6.8, 95% confidence interval 1.3-33.4, P=0.01), the G genotype of rs11902171 (ITGV) (OR for hematogenous metastases: 2.5, 95% confidence interval 1.1-5.7, P = 0.02), diffuse histology (OR for peritoneal carcinosis: 4.7, 95% confidence interval 1.9-11.3, P=0.0005) and intestinal histology (OR for hematogenous metastases: 4.2, 95% confidence interval 1.9-9.9, P=0.0008).

CONCLUSIONS

Tumor histology represents a crucial issue conditioning tumoral behavior; genotyping of rs2269772 (ITGA3) and rs11902171 (ITGV) may be a further asset in the definition of high-risk patients for peritoneal carcinosis among those relapsing after curative resection. The selection tool deriving from this analysis may allow an optimal use of innovative treatment strategies.

Aberrant gene methylation in the peritoneal fluid is a risk factor predicting peritoneal recurrence in gastric cancer

AIM: To investigate whether gene methylation in the peritoneal fluid (PF) predicts peritoneal recurrence in gastric cancer patients.

METHODS: The gene methylation of CHFR (checkpoint with forkhead and ring finger domains), p16, RUNX3 (runt-related transcription factor 3), E-cadherin, hMLH1 (mutL homolog 1), ABCG2 (ATP-binding cassette, sub-family G, member 2) and BNIP3 (BCL2/adenovirus E1B 19 kDa interacting protein 3) were analyzed in 80 specimens of PF by quantitative methylation-specific polymerase chain reaction (PCR). Eighty patients were divided into 3 groups; Group A (n = 35): the depth of cancer invasion was less than the muscularis propria; Group B (n = 31): the depth of cancer invasion was beyond the muscularis propria. Both group A and B were diagnosed as no cancer cells in peritoneal cytology and histology; Group C (n = 14): disseminated nodule was histologically diagnosed or cancer cells were cytologically defined in the peritoneal cavity.

RESULTS: The positive rates of methylation in CHFR, E-cadherin and BNIP3 were significantly different among the 3 groups and increased in order of group A, B and C (0%, 0% and 21% in CHFR, P < 0.05; 20%, 45% and 50% in E-cadherin, P < 0.05; 26%, 35% and 71% in BNIP3, P < 0.05). In addition, the multigene methylation rate among CHFR, E-cadherin and BNIP3 was correlated with group A, B and C (9%, 19% and 57%, P < 0.001). Moreover, the prognosis was analyzed in group B, excluding 3 patients who underwent a non-curative resection. Two of the 5 patients with multigene methylation showed peritoneal recurrence after surgery, while those without or with a single gene methylation did not experience recurrence (P < 0.05).

CONCLUSION: This study suggested that gene methylation in the PF could detect occult neoplastic cells in the peritoneum and might be a risk factor for peritoneal metastasis.

Positive peritoneal washing cytology in multiple cavities can predict poor prognosis of advanced gastric cancer patients

BACKGROUND

Positive peritoneal washing cytology (PWC) has been reported to be a poor prognostic factor for gastric cancer. Japanese gastric cancer classifications recommend PWC in Douglas' pouch for advanced gastric cancer. However, the sensitivity of PWC is relatively low. The goal of this study was to investigate whether PWC in multiple cavities increases its sensitivity to predict prognosis.

METHODS

Between January 1996 and December 2006, a series of 992 patients with gastric cancer underwent D2 gastrectomy with intraoperative PWC. Of the 992 patients, 62 patients had positive PWC. PWC was conducted in four cavities (left subphrenic cavity, right subhepatic cavity, Douglas' pouch, and inside the omental bursa). The 62 patients were retrospectively analyzed for their background and survival.

RESULTS

Eleven (17.7%) patients had negative PWC in Douglas' pouch but were positive in the other cavities. The 62 patients were classified into two groups according to the number of positive PWC cavities: 20 patients with one or two and 42 patients with three or four positive PWC cavities. No significant difference in clinicopathological features was observed between these two groups. However, the overall and progression-free survival rates of patients with one or two positive PWC cavities were significantly higher than those for patients with three or more positive PWC cavities.

CONCLUSION

PWC in multiple cavities was more sensitive than only in one cavity. The number of positive cavities may indicate the grade of tumor spread in the peritoneum and predict the prognosis of patients with positive PWC.

The clinical significance of ascitic fluid CEA in advanced gastric cancer with ascites

BACKGROUND

This study was carried out to evaluate the clinical significance of ascitic fluid carcinoembryonic antigen (CEA) in advanced gastric cancer patients with ascites.

PATIENTS AND METHODS

From November 2001 to February 2008, 119 gastric cancer patients with concurrent ascites who were clinically diagnosed with carcinomatosis, were retrospectively reviewed with regard to ascitic fluid cytology and clinicopathological parameters. Serum CEA (sCEA) and ascitic fluid CEA (aCEA) were measured using a chemiluminescent enzyme immunoassay.

RESULTS

The patients' median age was 50 years (range 23-80 years). The median value of aCEA was significantly higher than sCEA [130.5 ng/ml (range 0.2-12.211 ng/ml) vs. 2.1 ng/ml (range 0.02-8.152 ng/ml), p < 0.001]. Sixty-five patients (54.6%) had positive ascitic fluid cytology. The median overall survival of all patients was 3.0 months (95% CI 2.0-4.0 months). The patients with low aCEA (<5 ng/ml) had a significantly longer overall survival compared to patients with high aCEA (>or=5 ng/ml) (7.4 months vs. 2.3 months, p = 0.003). However, we found no difference in overall survival according to ascitic fluid cytology (median, 3.0 months vs. 2.5 months, p = 0.530). Multivariate analysis also demonstrated that aCEA levels of more than 5 ng/ml were associated with poor prognosis (HR = 2.88; 95% CI 1.45-5.74; p = 0.003), while sCEA levels were not associated with poor prognosis (HR = 1.15; 95% CI 0.67-2.03; p = 0.622).

CONCLUSION

These results suggest that aCEA levels can be used as a prognostic marker for advanced gastric cancer patients with ascites.

Destruction of gastric cancer cells to mesothelial cells by apoptosis in the early peritoneal metastasis

This study examined the mechanism by which the gastric cancer cells lead to early peritoneal metastasis. HMrSV5 cells, a human peritoneal mesothelial cell line, were co-incubated with the supernatants of gastric cancer cells. Morphological changes of HMrSV5 cells were observed. The cell damage was quantitatively determined by MTT assay. The apoptosis of HMrSV5 cells was observed under transmission electron microscope. Acridine orange/ethidium bromide-stained condensed nuclei was detected by fluorescent microscopy and flow cytometry. The expressions of Bcl-2 and Bax was immunochemically evaluated. The results showed that conspicuous morphological changes of apoptosis were observed in HMrSV5 cells 24 h after treatment with the supernatants of gastric cancer cells. The supernatants could induce apoptosis of HMrSV5 cells in a time-dependent manner. The supernatants could up-regulate the expression of Bax and suppress that of Bcl-2 in HMrSV5 cells. These findings demonstrated that gastric cancer cells can induce the apoptosis of HPMCs through supernatants in the early peritoneal metastasis. The abnormal expressions of Bcl-2 and Bax may contribute to the apoptosis. Anti-apoptosis drugs promise to be adjuvant chemotherapeutic agents in the treatment of peritoneal metastasis of gastric cancer.

Regional administration of oncolytic Echovirus 1 as a novel therapy for the peritoneal dissemination of gastric cancer

The dissemination of malignant gastric cells to the peritoneum occurs frequently, usually as an early event in disease, and results in poor patient prognosis. Surgery and chemotherapy offer limited therapeutic success. The low-pathogenic human enterovirus, Echovirus 1 (EV1), is an oncolytic virus that selectively targets and destroys malignant prostate and ovarian cancer xenografts in vivo. Lytic EV1 infection requires the cell surface expression of alpha(2)beta(1), an integrin involved in the dissemination of gastric cancer cells to the peritoneum. Herein, we evaluated the capacity of EV1 for anti-neoplastic cell action in gastric peritoneal carcinomatosis. Flow cytometric analysis demonstrated that alpha(2)beta(1) was abundantly surface expressed on a panel of gastric cancer cell lines, rendering the majority of lines highly susceptible to in vitro lytic EV1 infection and supportive of efficient viral progeny production. A bioluminescent MKN-45-Luc SCID mouse model of peritoneal dissemination was developed to allow real-time non-invasive monitoring of peritoneal tumor burden. Employing this mouse model, we demonstrated a therapeutic dose-response for escalating oncolytic EV1 doses. Taken together, these results emphasize the exciting potential for EV1 as a single or adjunct therapy for the control of the peritoneal dissemination of gastric cancer.