Quantitative detection of disseminated free cancer cells in peritoneal washes with real-time reverse transcriptase-polymerase chain reaction: a sensitive predictor of outcome for patients with gastric carcinoma

Disparities of tumour markers in intraperitoneal drainage fluid between laparoscopic and open radical gastrectomy for gastric cancer

Introduction

Despite the remarkable progress in minimally invasive surgery, the potential association between laparoscopic gastrectomy and the risk of peritoneal metastasis remains uncertain.

Aim

To investigate variations in tumour markers in intraperitoneal drainage fluid between laparoscopic radical gastrectomy and open radical gastrectomy for gastric cancer.

Material and methods

A total of 106 patients diagnosed with gastric cancer between July 2018 and November 2020 were included in this study, 45 of whom underwent laparoscopic radical gastrectomy (laparoscopic group) and 61 underwent open radical gastrectomy (open group). Variations in the levels of carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), cancer antigen 199 (CA199), and α-fetoprotein (AFP) in the intraperitoneal drainage fluid were compared and analysed on postoperative days (PODs) 1, 2, 3, and 5 between the two groups. Additionally, the postoperative 3-year survival rates between the two groups were compared and analysed.

Results

No significant differences in CEA, CA199, and AFP levels in the intraperitoneal drainage fluid were observed between the two groups on postoperative days (PODs) 1, 2, 3, and 5 (p > 0.05). However, the level of CA125 in the intraperitoneal drainage fluid of the laparoscopic group was notably higher than that of the open group on POD 2 (p < 0.05); however, there were no significant differences between the two groups on PODs 1, 3, and 5 (p > 0.05). There was no significant difference in the 3-year postoperative survival rates between the two groups.

Conclusions

There were no significant differences in CEA, CA125, CA199, and AFP levels in the intraperitoneal drainage fluid between laparoscopic radical gastrectomy and open radical gastrectomy for gastric cancer, confirming from another perspective that laparoscopic radical gastrectomy does not increase the risk of intraperitoneal metastasis.

Techniques of staging laparoscopy and peritoneal fluid assessment in gastric cancer: a systematic review

BACKGROUND

Staging laparoscopy for gastric cancer is recommended to assess the tumor's locoregional extension and exclude peritoneal disease. As there is no consensus on optimizing the procedure's diagnostic accuracy, we aimed to systematically review the literature on operative techniques, followed by peritoneal lavage fluid assessment in gastric cancer patients. Specifically, we sought to indicate the most common characteristics of the procedure and cytological evaluation.

METHODS

This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The protocol for this systematic review was registered on PROSPERO database (CRD: 42022306746). On September 2022, a search was carried out using Embase, Medline ALL, Cochrane Central Register of Controlled Trials, and Web of Science Core Collection.

RESULTS

The search identified 1632 studies on staging laparoscopy and 2190 studies on peritoneal fluid assessment. Some 212 studies were included. Open Hasson was the method of choice in accessing the peritoneal cavity in 65% of the studies, followed by establishing a pneumoperitoneum at 10-12 mmHg in 52% of reports. Most frequently, the patient was positioned supine (70%), while a 30° scope and three ports were used to assess the peritoneal cavity clockwise (72%, 77%, and 85%, respectively). Right and left upper abdomen quadrants were the predominant area of laparoscopic exploration (both 65%), followed by the primary tumor region (54%), liver and pelvis (both 30%), and small bowel and spleen (19% and 17%, respectively). Regions of peritoneal lavage and aspiration were limited to the pelvis (50%), followed by right and left upper abdomen quadrants (37.5% and 50%, respectively). No studies compared different methods of operative techniques or analysis of ascites/fluid.

CONCLUSIONS

This study indicates a high heterogeneity in the technique of staging laparoscopy and peritoneal fluid assessment in gastric cancer patients. Further research and initiatives to reach a consensus on the standardization of the procedure are warranted.

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.

Accurate and Rapid Detection of Peritoneal Metastasis from Gastric Cancer by AI-Assisted Stimulated Raman Molecular Cytology

Peritoneal metastasis (PM) is the mostcommon form of distant metastasis and one of the leading causes of death in gastriccancer (GC). For locally advanced GC, clinical guidelines recommend peritoneal lavage cytology for intraoperative PM detection. Unfortunately, current peritoneal lavage cytology is limited by low sensitivity (<60%). Here the authors established the stimulated Raman molecular cytology (SRMC), a chemical microscopy-based intelligent cytology. The authors firstly imaged 53 951 exfoliated cells in ascites obtained from 80 GC patients (27 PM positive, 53 PM negative). Then, the authors revealed 12 single cell features of morphology and composition that are significantly different between PM positive and negative specimens, including cellular area, lipid protein ratio, etc. Importantly, the authors developed a single cell phenotyping algorithm to further transform the above raw features to feature matrix. Such matrix is crucial to identify the significant marker cell cluster, the divergence of which is finally used to differentiate the PM positive and negative. Compared with histopathology, the gold standard of PM detection, their SRMC method could reach 81.5% sensitivity, 84.9% specificity, and the AUC of 0.85, within 20 minutes for each patient. Together, their SRMC method shows great potential for accurate and rapid detection of PM from GC.

New diagnostic strategy using narrow-band imaging (NBI) during laparoscopic surgery for patients with colorectal cancer

BACKGROUND

Accurate tumor stage diagnosis during laparoscopic surgery remains difficult. We clarify the impact of new diagnostic strategy using narrow-band imaging (NBI) during laparoscopic surgery for colorectal cancer compared with other strategies.

METHODS

We defined angiogenesis (Ag) and fibrosis (Fib) grades using NBI laparoscopy (lap-NBI), and assessed the clinicopathological features associated with these grades for 67 patients with colorectal cancer who underwent surgery. We assessed vessel density and gray scale with computer software.

RESULTS

NBI-Ag-grade and NBI-Fib-grade of the serosal surface of cancer lesions and peritoneal nodules correlated with vessel density and gray scale of those assessed by Image J computer software. NBI-Fib-grades of liver nodules also correlated with gray scale. NBI-Ag- grade and Fib-grade of the serosal surface of cancer lesions correlated with pathological depth of invasion. These NBI grades of pathological metastatic peritoneal nodules were higher than those of pathologically benign peritoneal nodules. NBI- Fib grades of pathological metastatic liver nodules were higher than those of pathologically benign liver nodules. In multivariate analysis, lap-NBI was associated with different diagnosis for T3, T4 and non-T3, and non-T4. Moreover, lap-NBI was associated with different diagnosis for T4 and non-T4. Predictive value for T4 by lap-NBI showed high sensitivity (85%) specificity (87%), positive predictive value (74%), negative predictive value (93%), and overall accuracy (87%). Sensitivity and overall accuracy of lap-NBI was superior to that of other diagnostic modalities.

CONCLUSION

We clarified the usefulness of the new diagnostic strategy using lap-NBI during laparoscopic surgery for colorectal cancer in comparison with other strategies.

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.

Integrated Single-Cell RNA-Sequencing Analysis of Gastric Cancer Identifies FABP1 as a Novel Prognostic Biomarker

Gastric cancer (GC) is usually diagnosed in an advanced stage at the first visit due to the atypical clinical symptoms. The low surgical resection rate and chemotherapy sensitivity result in dismal survival. Therefore, it is urgent to develop novel biomarkers with high sensitivity and specificity to accurately assess the prognosis of GC patients. In the present study, 3385 differentially expressed genes (DEGs) were obtained from the single-cell RNA sequencing data of GC specimens. Using the unsupervised dimensionality reduction, we further found 3 subsets of cells including gastric cells, plasmacytoid dendritic cells, and memory T cells. Based on the cell clustering, we explored the key regulatory genes for GC progression by pseudo-time analysis and functional enrichment analysis. According to the results, the significant differentially expressed fatty acid-binding protein 1 (FABP1) verified by pseudo-time analysis was identified as the hub gene of GC progression. FABP1 was shown to be closely related to the long-term survival and the age at diagnosis of patients with GC in analysis based on the TCGA (The Cancer Genome Atlas) database. To further verify the role of FABP1 in GC, we performed immunohistochemical (IHC) analysis using the GC tissue microarray and found that the expression level of FABP1 was higher in GC tissues than in the adjacent tissues. Moreover, GC patients with higher expression of FABP1 had a worse clinical outcome. In summary, our study revealed that FABP1 is a potential effective biomarker for the prognosis of GC, and high expression of FABP1 predicts unsatisfactory survival.

PCR-based quantitative detection of intraperitoneal free cancer cells for predicting locoregional recurrence after rectal cancer resection

INTRODUCTION

Locoregional recurrence after curative resection remains an important issue in the treatment of colorectal cancer (CRC). The aim of the present study was to investigate the clinical significance of quantitative detection of intraperitoneal free cancer cells by a PCR-based method for predicting locoregional recurrence after CRC resection.

METHOD

A total of 114 patients with CRC were enrolled between March 2017 and December 2018, and 95 patients with Stage I-III CRC were analyzed. Peritoneal lavage fluid was collected before and after tumour resection and subjected to cytology and quantitative reverse transcription-PCR (qRT-PCR) with carcinoembryonic antigen (CEA) as a genetic marker.

RESULTS

2.1% of patients had positive cytology after resection, whereas 9.5% had positive CEA qRT-PCR (PCR+) after resection. Eight of nine PCR+ patients after resection had tumours in the rectum. Fifteen (15.8%) patients developed recurrence during the follow-up period, including three with locoregional recurrence. One of 86 (1.2%) PCR- patients and 2 of 9 (22.2%) PCR+ patients after resection developed locoregional recurrence. Overall and in rectal cancer patients, the 3-year cumulative risk of locoregional recurrence was 25.0% and 28.6% for PCR+ patients, which is significantly higher than PCR- patients (1.3% and 0%, P < 0.001 and P = 0.001, respectively).

CONCLUSION

Intraperitoneal free cancer cells can serve as a sensitive predictor of locoregional recurrence after rectal cancer resection. qRT-PCR for CEA can be a suitable method for detecting intraperitoneal free cancer cells in peritoneal lavage fluid.

The expression of carcinoembryonic antigen mRNA in the lavage of the dissected area of the lateral lymph nodes influences the lateral recurrence of lower rectal cancer

PURPOSE

To determine whether or not migrating cancer cells are present on the surgical plane after lateral lymph node dissection (LLND) for lower rectal cancer and related to lateral recurrence (LR), we evaluated the lavage of LLND areas by reverse-transcription polymerase chain reaction (RT-PCR) to check the expression of CEA mRNA in the residual cancer cells.

METHODS

Thirty patients who underwent curative LLND were enrolled. Lavage was collected after LLND and subjected to RT-PCR to detect CEA mRNA. The median follow-up to check for recurrence was 31.4 months.

RESULTS

CEA mRNA was detected in 9 of the 46 dissected areas. Based on the receiver operating characteristic curves, the cut-off value of PCR was set at 0.025. This cut-off point classified five patients into the high-expression group for CEA mRNA. During follow-up, LR developed in 1 of 40 low-expression areas of CEA mRNA and 3 of 6 high-expression areas. The LR rate was higher in the high-expression group than in the low-expression group (p = 0.015). A multivariate analysis showed that the high expression of CEA mRNA was likely an independent prognostic factor of LR.

CONCLUSION

The expression of CEA mRNA in the lavage of LLND areas indicates the presence of residual cancer cells that cause LR.

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.

Prospective study to validate the clinical utility of DNA diagnosis of peritoneal fluid cytology test in gastric cancer

The clinical efficacy of DNA cytology test (CY) in gastric cancer (GC) has been retrospectively proposed using cancer‐specific methylation of cysteine dioxygenase type 1 (CDO1). We confirmed the clinical utility of DNA CY in a prospective cohort. Four hundred GC samples were prospectively collected for washing cytology (UMIN000026191), and detection of the DNA methylation of CDO1 was assessed by quantitative methylation‐specific PCR in the sediments. Endpoint was defined as the match rate between conventional CY1 and DNA CY1 (diagnostic sensitivity), and the DNA CY0 rate (diagnostic specificity) in pStage IA. DNA CY1 was detected in 45 cases (12.5%), while CY1 was seen in 31 cases (8.6%) of 361 chemotherapy‐naïve samples, where the sensitivity and specificity of the DNA CY in the peritoneal solutions were 74.2% and 96.5%, respectively. The DNA CY was positive for 3.5/0/4.9/11.4/58.8% in pStage IA/IB/II/III/IV, respectively (P < .01). In the multivariate analysis, DNA CY1 was independently correlated with pathological tumor depth (pT) (P = .0012), female gender (P = .0099), CY1 (P = .0135), P1 (P = .019), and carcinoembryonic antigen (CEA) (P = .036). The combination of DNA CY1 and P factor nearly all covered the potential peritoneal dissemination (P1 and/or CY1 and/or DNA CY1) (58/61:95.1%). DNA CY1 had a significantly poorer prognosis than DNA CY0 in GC patients (P < .0001). DNA CY1 detected by CDO1 promoter DNA methylation has a great value to detect minimal residual disease of the peritoneum in GC clinics, representing poor prognosis as a novel single DNA marker.

Flow cytometry-based analysis of tumor-leukocyte ratios in peritoneal fluid from patients with advanced gastric cancer

Background

The frequency of tumor cell dissemination in the peritoneal cavity is critically related to the progression of peritoneal metastases (PM). Recently, flow cytometry (FCM) has been successfully used to detect tumor cells in malignant effusions.

Methods

A total of 143 single cell suspensions derived from ascites or peritoneal lavages from patients with advanced gastric cancer (GC) were stained with monoclonal antibodies to CD45 and to CD326 as well as 4,6‐diamidino‐2‐phenylindole (DAPI) and FVS780. Using FCM, tumor‐leukocyte ratio (TLR) were calculated from CD45(−)CD326(+) tumor cell counts/ CD45(+)CD326(+) leukocyte counts in DAPI (+) FVS780(−) gated area. In 54 patients, the ratios of CD11b(+), CD4(+) and CD8(+) cells in CD45(+) leukocytes were evaluated in parallel.

Results

TLR of 69 patients with PM were significantly higher than those of 74 without PM (p < .001) and log(TLR) showed strong correlation with peritoneal cancer index scores in 51 PM (+) patients (r = 0.439). TLR in PM (+) patients also correlated with the ratio of CD11b (+) myeloid cells (r = 0.547), and correlated inversely with those of CD4(+) (r = −0.490) and CD8(+) T cells (r = −0.648). In PM (−) patients who underwent gastrectomy, TLR never exceeded 0.1% in patients with primary GC without serosal involvement (<T4). However, TLR in patients with T4 GC were significantly higher (p < .05) and peritoneal recurrence occurred in 6/8 patients whose TLR exceeded 0.1%.

Conclusion

TLR in peritoneal fluid reflects tumor burden and the immune environment in peritoneal cavity. Multicolor FCM may provide additional information which can be used for the treatment of the patients with PM.

Detection and isolation of free cancer cells from ascites and peritoneal lavages using optically induced electrokinetics (OEK)

Detection of free gastric cancer cells in peritoneal lavages and ascites plays a vital role in gastric cancer. However, due to the low content of cancer cells in patients' peritoneal lavages, traditional detection methods lack sensitivity and cannot satisfy clinical demand. In this study, we used an optically induced electrokinetics (OEK) microfluidic method for label-free separation and characterization of patient gastric cancer cells. This method showed high effectiveness and sensitivity. We successfully separated cancer cells from a simulated peritoneal lavage mixture of gastric cancer cell lines and peritoneal lavage cells in a ratio of 1:1000. We further separated gastric cancer cells from six patients' ascites with purity up to 71%. In addition, we measured the cell membrane capacitances, which may be used as a biomarker for gastric cancer cells. Thus, our method can be used to effectively and rapidly detect peritoneal metastasis and to acquire cellular electrical information.

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.

Rational design of small molecule RHOA inhibitors for gastric cancer

Previously, we identified Ras homologous A (RHOA) as a major signaling hub in gastric cancer (GC), the third most common cause of cancer death in the world, prompting us to rationally design an efficacious inhibitor of this oncogenic GTPase. Here, based on that previous work, we extend those computational analyses to further pharmacologically optimize anti-RHOA hydrazide derivatives for greater anti-GC potency. Two of these, JK-136 and JK-139, potently inhibited cell viability and migration/invasion of GC cell lines, and mouse xenografts, diversely expressing RHOA. Moreover, JK-136's binding affinity for RHOA was >140-fold greater than Rhosin, a nonclinical RHOA inhibitor. Network analysis of JK-136/-139 vs. Rhosin treatments indicated downregulation of the sphingosine-1-phosphate, as an emerging cancer metabolic pathway in cell migration and motility. We assert that identifying and targeting oncogenic signaling hubs, such as RHOA, represents an emerging strategy for the design, characterization, and translation of new antineoplastics, against gastric and other cancers.

The levels of SYT13 and CEA mRNAs in peritoneal lavages predict the peritoneal recurrence of gastric cancer

BACKGROUND

Although peritoneal lavage cytology often serves as a sensitive method to detect free cancer cells in the abdominal cavity, some patients experience peritoneal recurrence despite negative cytology. The aim of this study was to evaluate mRNAs in peritoneal lavage fluid as potential markers for predicting the peritoneal recurrence of gastric cancer (GC).

METHODS

Peritoneal lavage fluid samples were obtained during surgery conducted on 187 patients with GC and from 30 patients with non-malignant disease (controls). The mRNA levels of nine candidate markers were quantified, and analysis of a receiver-operating characteristic curve compared their accuracies. The cutoff was defined as the highest value of the controls.

RESULTS

Synaptotagmin XIII (SYT13) and carcinoembryonic antigen (CEA) mRNA levels were analyzed further. SYT13 levels were significantly associated with shorter peritoneal recurrence-free survival (PRFS) and overall survival. Among patients with negative peritoneal lavage cytology, those positive for either SYT13 or CEA mRNA experienced significantly shorter peritoneal recurrence-free survival compared with those with negative fluid (hazards ratio [HR] 4.21, P = 0.0114; HR 3.53; P = 0.0426, respectively). Univariate analysis revealed that SYT13 and CEA mRNA levels were significant predictors of peritoneal recurrence. Positive levels of both SYT13 and CEA mRNA demonstrated the highest HR for peritoneal recurrence (HR 12.27, P = 0.0064). Multivariable analysis revealed that SYT13 positivity was a significant independent prognostic factor (HR 3.69; 95% confidence interval, 1.18-12.74; P = 0.0246).

CONCLUSIONS

Combined measurement of SYT13 and CEA mRNA levels in peritoneal lavage fluid could serve as a promising approach to predict peritoneal recurrence of GC.

Review and Update on the Role of Peritoneal Cytology in the Treatment of Gastric Cancer

BACKGROUND

Positive peritoneal cytology (Cyt+) even in the absence of macroscopic disease is associated with poor prognosis in patients with gastric cancer and deemed as M1 disease. Recent years have seen advancements in the evaluation strategies for peritoneal washings and management of patients with Cyt+. The aim of this review was to describe the newest paradigms in the management of patients with gastric cancer who have Cyt+ without macroscopic peritoneal metastases.

METHODS

A comprehensive literature review was performed to identify studies on the management of gastric cancer and thereby to summarize relevant information on the accuracy of various diagnostic tests and controversies involved in the treatment of patients with Cyt+.

RESULTS

Although conventional cytology remains the standard technique for assessment of peritoneal washings, it is limited by low sensitivity. The role of immunohistochemistry and molecular techniques for the assessment of peritoneal washings is evolving. Although systemic chemotherapy remains the standard of care for patients with Cyt+ disease, the role of gastrectomy, intraperitoneal chemotherapy, extensive intraperitoneal saline lavage, and hyperthermic intraperitoneal chemotherapy is being evaluated.

CONCLUSIONS

Clinical decision-making in patients with Cyt+ remains controversial given the seemingly technical resectable albeit biologically unresectable or aggressive disease that portends an overall poor prognosis. Current management strategies are evolving, and further studies are needed to develop an optimal treatment strategy for these patients.

Epigenetic biomarkers of promoter DNA methylation in the new era of cancer treatment

Promoter DNA methylation, which occurs on cytosine nucleotides across CpG islands, results in gene silencing and represents a major epigenetic alteration in human cancer. Methylation-specific PCR can amplify these modifications as markers in cancer cells. In the present work, we rigorously review the published literatures describing DNA methylation in the promoters of critical tumor suppressor genes; detection of promoter DNA methylation in various body fluids permits early detection of cancer cells during perioperative courses of clinical treatment. The latest whole-genome comprehensive explorations identified excellent epigenetic biomarkers that could be detected at high frequency with high specificity; these biomarkers, which are designated highly relevant methylation genes (HRMG), permit the discrimination of tumor tissues from the corresponding normal tissues; these markers are also associated with unique cancer phenotypes, including dismal prognosis. In humans, HRMG include the CDO1, GSHR, RASSF1 and SFRP1 genes, with these markers permitting discrimination depending on the organs tested. The combination of several HRMG increased the early detection of cancer and exhibited reliable surveillance potential in human body fluids. Cancer clinics using such epigenetic biomarkers are entering a new era of enhanced decision-making with the potential for improved cancer prognosis.

Integrated fluorescent cytology with nano-biologics in peritoneally disseminated gastric cancer

Gastric cancer patients positive for peritoneal cytology are at increased risk of tumor recurrence, but although a certain proportion of cytology‐positive patients relapse rapidly with aggressive progression, others survive longer with conventional chemotherapies. This heterogeneity makes it difficult to stratify patients for more intensive therapy and poses a substantial challenge for the implementation of precision medicine. We developed a new approach to identify biologically malignant subpopulations in cytology‐positive gastric cancer patients, using a green fluorescent protein (GFP)‐expressing attenuated adenovirus in which the telomerase promoter regulates viral replication (TelomeScan, OBP‐401). The fluorescence emitted from TelomeScan‐positive cells was successfully quantified using a multi‐mode microplate reader. We then analyzed clinical peritoneal washes obtained from 68 gastric cancer patients and found that patients positive for TelomeScan had a significantly worse prognosis. In 21 cytology‐positive patients, the median survival time of those who were TelomeScan positive (235 days) was significantly shorter than that for those who were TelomeScan negative (671 days; P = 0.0062). This fluorescent virus‐guided cytology detects biologically malignant cancer cells from the peritoneal washes of gastric cancer patients and may thus be useful for both therapy stratification and precision medicine approaches based on genetic profiling of disseminated cells.

Clinical significance of circulating tumor cells in gastric cancer patients

Circulating tumor cells (CTCs) are rare cancer cells released from tumors into the blood stream that are thought to have a key role in cancer metastasis. Investigation of CTCs is an exciting area of research but remains in its infancy, and the presence of CTCs has been associated with worse prognosis in several major cancer types. Gastric cancer (GC) is a highly lethal malignancy and a serious public health concern in East Asia especially in China. There is an urgent need for identifying new, better prognostic markers to enhance diagnosis and prognosis, facilitate drug development, and to improve the treatment of gastric cancer patients. There are considerable interests in gastric CTCs given their potential use as gastric cancer biomarkers. This review highlights recent advances in studies of gastric CTCs, including the isolation and biological molecular characteristics of gastric CTCs, and their clinical significance.

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.

Peritoneal recurrence in gastric cancer following curative resection can be predicted by postoperative but not preoperative biomarkers: a single-institution study of 320 cases

To determine the risk factors for peritoneal recurrence in gastric cancer patients after curative resection, we included 320 patients with stage I-III primary gastric cancer between January 2008 and June 2012. Data on each patient's surgical and pathological information, preoperative and postoperative tumor markers were collected and analyzed retrospectively. The risk factors for peritoneal recurrence were investigated by univariate and multivariate analysis. In patients with peritoneal recurrence, advanced T or N stage, low differentiation, vascular/lymphatic invasion, perineural invasion, and elevated postoperative CEA/CA19-9 were more common than in patients without peritoneal recurrence. Patients with peritoneal recurrence showed a worse overall survival (OS) compared to those without peritoneal recurrence. In addition, patients with peritoneal recurrence within the first year had a worse OS compared to those with recurrence after 1 year. The univariate and multivariate analyses revealed that elevated number of metastatic lymph nodes and elevated postoperative CEA and CA19-9 were three independent risk factors for peritoneal recurrence in gastric cancer patients. For patients with N3 stage and high postoperative CEA and CA19-9, we found an initial steep slope within approximately 1 year and a subsequent gentle slope in the risk curve. Combined receiver operating characteristic curve analysis using the three independent risk factors for peritoneal recurrence yielded an area under the curve value of 0.73 with 73.7% sensitivity and 64.2% specificity. Therefore, the risk factors may be associated with peritoneal recurrence after curative resection in selected gastric cancer patients.

Circulating tumor cell as a biomarker for evaluating allogenic NK cell immunotherapy on stage IV non-small cell lung cancer

In this study, we determined the number of peripheral blood circulating tumor cells (CTCs) pre- and post-NK in patients with stage IV non- small cell lung cancer (NSCLC) as a reference for understanding the relevance of any changes to the efficacy of NK cells therapy. The patients were given one to three courses of immunotherapy. CTC numbers and CTC-related gene expression were measured in the peripheral blood of 31 patients with stage IV NSCLC at 1day before and 7 and 30d after NK cells therapy using magnetic activated cell sorting (MACS) and fluorescence activated cell sorting (FACS) combined with real-time quantitative PCR (RT-qPCR). Throughout the research, fever was the most common reaction (34.6%). The number of CTCs was 18.11±5.813, 15.13±5.984 and 10.32±5.623, respectively, and this decreased significantly over time. ΔCt values for the CTC-related genes CEA, MAGE-3 and CK18 increased significantly after NK cells infusion. The expression of CEA, CK18 and MAGE-3 decreased significantly with time after NK. CTC was a useful biomarker for evaluating the efficacy of NK cells therapy on stage IV NSCLC.

DNA diagnosis of peritoneal fluid cytology test by CDO1 promoter DNA hypermethylation in gastric cancer

BACKGROUND

Minimal residual disease of the peritoneum is challenging for early cancer detection in gastric cancer (GC). Utility of PCR amplification of cancer-derived DNA has been considered feasible due to its molecular stability, however such markers have never been available in GC clinics. We recently discovered cancer-specific methylation of CDO1 gene in GC, and investigated the clinical potential to detect the minimal residual disease.

METHODS

One hundred and two GC patients were investigated for peritoneal fluid cytology test (CY), and detection level of the promoter DNA methylation of CDO1 gene was assessed by quantitative methylation specific PCR (Q-MSP) in the sediments (DNA CY).

RESULTS

(1) CY1 was pathologically confirmed in 8 cases, while DNA CY1 was detected in 18 cases. All 8 CY1 were DNA CY1. (2) DNA CY1 was recognized in 14.3, 25.0, 20.0, and 42.9%, in macroscopic Type II, small type III, large type III, and type IV, respectively, while it was not recognized in Type 0/I/V. (3) DNA CY1 was prognostic relevance in gastric cancer (p = 0.0004), and its significance was robust among Type III/IV gastric cancer (p = 0.006 for overall survival and p = 0.0006 for peritoneal recurrence free survival). (4) The peritoneal recurrence was hardly seen in GC patients with potent perioperative chemotherapy among those with DNA CY1.

CONCLUSIONS

DNA CY1 detected by Q-MSP for CDO1 gene promoter DNA methylation has a great potential to detect minimal residual disease of the peritoneum in GC clinics as a novel DNA marker.

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.

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.

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.

Circulating tumour cells as biomarkers for evaluating cryosurgery on unresectable hepatocellular carcinoma

We evaluated the efficacy of pre-cryosurgery and post-cryosurgery circulating tumour cells (CTCs) as biomarkers for unresectable hepatocellular carcinoma (HCC). Real‑time qPCR was used to detect potential biomarker genes in CTCs, and magnetic-activated cell sorting (MACS) and fluorescence‑activated cell sorting (FACS) was performed on 47 patients with hepatocellular cancer who underwent cryosurgery. CTCs in the 47 patients were assessed 1 day before cryosurgery, and 7 and 30 days after cryosurgery. The number of CTCs was 17.70±5.725, 14.64±6.761 and 10.28±5.598, respectively, and this decreased significantly over time (P<0.01). ΔCt values for MAGE-3, survivin and carcinoembryonic antigen (CEA) were elevated significantly compared with those obtained before cryosurgery; 2-ΔΔCt values were <1 before cryosurgery, and were 0.63±1.56, 0.21±0.22 and 0.22±0.34 for MAGE-3, survivin and CEA, respectively, at 7 days after treatment. At 30 days after treatment, 2-ΔΔCt values for MAGE-3, survivin and CEA were 0.24±0.82, 0.03±0.07 and 0.02±0.08, indicating that gene expression in CTCs significantly decreased over time (P<0.01). CTCs were useful biomarkers for evaluating the efficacy of cryosurgery on unresectable HCC.

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.

Analysis of circulating tumor cells in colorectal cancer liver metastasis patients before and after cryosurgery

In this study, we determined the number of peripheral blood circulating tumor cells (CTCs) pre- and post-cryosurgery in patients with colorectal cancer liver metastasis as a reference for understanding the relevance of any changes to the efficacy of cryosurgery. CTC numbers and CTC-related gene expression were measured in the peripheral blood of 55 patients with colorectal liver metastasis at 1 day before and 7 and 30 d after cryoablation using magnetic activated cell sorting (MACS) and fluorescence activated cell sorting (FACS) combined with real-time quantitative PCR (RT-qPCR). The number of CTCs decreased significantly with postoperative time (P < 0.01). Delta cycle threshold values for the CTC-related genes CEA, Ep-CAM, CK18 and CK19 increased significantly after cryoablation. Furthermore, the expression of CEA, Ep-CAM, CK18 and CK19 decreased significantly with time after cryoablation (P < 0.01). RT-qPCR and FACS combined with MACS has significant diagnostic and prognostic value for evaluating the efficacy of cryosurgery in patients with advanced colorectal cancer.

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.

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 application of omental bursa wash detection in gastric carcinoma

AIM: To evaluate the application value of omental bursa wash detection in gastric carcinoma.

METHODS: Omental bursa washes from 78 patients with gastric carcinoma were collected. The expression of carcino-embryonic antigen (CEA) in omental bursa washes was detected by flow cytometry (FCM). Peritoneal lavage cytology (PLC) examinations were also carried out.

RESULTS: The FCM and PLC positive rates of omental bursa washes were 37.1% (29/78) and 11.5% (9/78), respectively, which had a significant difference (P = 0.001). The positive rate of omental bursa washes correlated well with the width of tumor, location of lesion, and depth of invasion (P < 0.05). The age, gender, differentiation, vessel carcinoma embolus, and area of invasion were not relevant to omental bursa wash detection.

CONCLUSION: FCM can be well used to detect omental bursa washes. The best use of omental bursa wash detection is to assess tumor progression and to predict the emergence of gastric carcinoma micrometastases.

Factors predicting peritoneal recurrence in advanced gastric cancer: implication for adjuvant intraperitoneal chemotherapy

BACKGROUND

Despite adjuvant chemotherapy, patients with advanced gastric cancer (AGC) often develop recurrence, and the peritoneum is the most common site of recurrence. Therefore, intraperitoneal chemotherapy (IPC) has been proposed as a treatment option. The aim of this study was to select the eligible patients for application of IPC.

METHODS

A total of 805 patients with AGC who underwent curative D2 gastrectomy between May 2003 and December 2009 were included in this study. Risk factors for peritoneal recurrence were analyzed.

RESULTS

Recurrence developed in 245 patients (30.4 %). The first site of recurrence was the peritoneum in 144 patients (58.8 %), and the 5-year peritoneal recurrence-free survival was 79.3 %. Depth of tumor invasion ≥T3, extensive lymph node metastasis (N3), Bormann type 4, infiltrative type (Ming's classification), and venous invasion were independent risk factors for peritoneal recurrence. In subgroup analysis with patients who had received adjuvant chemotherapy (n = 481), depth of tumor invasion ≥T3, Bormann type 4, infiltrative type (Ming's classification), and venous invasion were independent risk factors for peritoneal recurrence. When a peritoneal recurrence risk index was made with each risk factor assigned 1 point (2 points for T4 stage), peritoneal recurrence rates with 0, 1, 2, 3, 4, or 5 points were 0 %, 3.9 %, 13.1 %, 33.3 %, 44.0 %, and 72.0 %, respectively, in those patients.

CONCLUSIONS

Patients at higher risk for peritoneal recurrence can be identified from the findings of this study. Further prospective studies are required to evaluate the usefulness of IPC for these patients.

Flow Cytometric Quantification of Intraperitoneal Free Tumor Cells is a Useful Biomarker in Gastric Cancer Patients with Peritoneal Metastasis

BACKGROUND

The frequency of intraperitoneal free tumor cells (IPTC) is considered to reflect the severity of peritoneal metastasis (PM). We quantified the relative number of IPTC against leukocytes in peritoneal fluid and evaluated its clinical relevance in gastric cancer (GC) patients, particularly those with PM.

METHODS

Cells recovered from ascites or peritoneal lavage fluid were immunostained with monoclonal antibodies (mAb) to CD45 and CD326 (EpCAM). Using flow cytometry (FACS), CD326(+) and CD45(+) cells were classified as either tumor cells (T) or leukocytes (L) and the T/L ratio (TLR) was calculated in a total of 506 samples obtained from 300 patients with GC and 33 patients with liver cirrhosis (LC).

RESULTS

Median (M) of the TLR of the initial samples obtained from 199 patients with PM(+) GC was 1.32 % (0-1,868.44 %), which was significantly higher than that in patients with PM(-) GC (M = 0 %, 0-0.35 %; n = 101) or LC (M = 0 %, 0-0.031 %; n = 33). In 104 PM(+) patients who received combination chemotherapy including intraperitoneal paclitaxel, the TLR was repeatedly measured in peritoneal fluid obtained from the port. In these patients, the TLR showed a strong correlation with clinical features as well as cytological findings and carcinoembryonic antigen messenger RNA status. Finally, the median survival time of the 11 patients with initial TLR > 10 % was significantly shorter than that of the 52 patients with TLR < 10 % (271 vs. 627 days; p = 0.0002).

CONCLUSION

The TLR excellently reflected tumor burden in the peritoneal cavity, and could be a reliable biomarker to determine the outcome, as well as the effectiveness, of chemotherapy in patients with PM(+) GC.

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.

Laparoscopic narrow-band imaging for the diagnosis of peritoneal metastasis in gastric cancer

BACKGROUND

Staging laparoscopy (SL) is often used to diagnose peritoneal metastasis in patients with advanced gastric cancer, but accurate detection of metastasis can be difficult. We evaluated the usefulness of laparoscopic narrow-band imaging (NBI) versus conventional laparoscopic white-light imaging (WLI) for the diagnosis of peritoneal metastasis.

METHODS

We excised 37 white nodules from the parietal peritoneum of 26 patients with gastric cancer and suspected peritoneal metastasis. The WLI and NBI findings were compared with the pathological findings. All the peritoneal lesions examined were observed as white nodules on WLI. Intranodular vessels were evaluated by WLI and NBI for (1) vessel dilatation, (2) vessel tortuousness, (3) vessel heterogeneity, and (4) brown spots.

RESULTS

Each individual abnormal finding had a diagnostic accuracy of less than 79 % with or without NBI. Detection of any one abnormal finding had a sensitivity, specificity, and accuracy of 47.8, 85.7, and 62.2 %, respectively, on WLI and 91.3, 71.4, and 83.8 %, respectively, on NBI, for detection of peritoneal metastasis. Detection of any one abnormal finding on NBI plus clear demarcation of the nodule on WLI had a sensitivity of 91.3 %, specificity of 92.9 %, and accuracy of 91.9 % for detection of peritoneal metastasis. Pathological examination showed that a brown spot detected on NBI correlated with dilated vessels around cancer cells. Vascular endothelial growth factor was expressed in 76.2 % of peritoneal metastases.

CONCLUSIONS

NBI was more sensitive for the detection of dilated vessels than WLI. NBI could be a useful tool for the diagnosis of peritoneal metastasis during SL.

Intraperitoneal Paclitaxel is useful as adjuvant chemotherapy for advanced gastric cancer with serosal exposure

BACKGROUND

Intraperitoneal administration of paclitaxel (PTX) can elicit a marked clinical response in peritoneal metastases of gastric cancer.

METHODS

In this study, we retrospectively analyzed the clinical outcome of 17 patients who underwent R0 resection with D2 dissection for advanced gastric cancer with macroscopic serosal exposure and received intraperitoneal PTX as adjuvant therapy.

RESULTS

A pathological study revealed that the depth of invasion of the primary tumor was pT4a or pT4b in 10 cases, and that the pN stage was more than pN2 in 8 cases. Genetic analysis of peritoneal lavage fluid was performed in 14 cases, all of which were positive for carcinoembryonic antigen mRNA. In these patients, PTX was intraperitoneally administered at 20-60 mg/m(2) with oral S-1 for 3-36 months after surgery. In a median follow-up period of 66 months, recurrence occurred in the liver and peritoneum in 2 (11.7%) and 1 (5.9%) patients, respectively, and no nodal recurrence was observed. Five-year overall survival and disease-free survival were 88.2 and 82.3%, respectively.

CONCLUSION

Since these patients are considered to be a high-risk group for peritoneal recurrence, this result strongly suggests that adjuvant chemotherapy including intraperitoneal PTX is a promising protocol to improve the outcome of patients with advanced gastric cancer with serosal exposure.

Test execution variation in peritoneal lavage cytology could be related to poor diagnostic accuracy and stage migration in patients with gastric cancer

PURPOSE

Peritoneal lavage cytology is part of the routine staging workup for patients with advanced gastric cancer. However, no quality assurance study has been conducted to show variations or biases in peritoneal lavage cytology results. The aim of this study was to demonstrate a test execution variation in peritoneal lavage cytology between investigating surgeons.

MATERIALS AND METHODS

A prospective cohort study was designed for determination of the positive rate of peritoneal lavage cytology using a liquid-based preparation method in patients with potentially curable advanced gastric cancer (cT2~4/N0~2/M0). One hundred thirty patients were enrolled and underwent laparotomy, peritoneal lavage cytology, and standard gastrectomy, which were performed by 3 investigating surgeons. Data were analyzed using the chi-square test and a logistic regression model.

RESULTS

The overall positive peritoneal cytology rate was 10.0%. Subgroup positive rates were 5.3% in pT1 cancer, 2.0% in pT2/3 cancer, 11.1% in pT4a cancer, and 71.4% in pT4b cancer. In univariate analysis, positive peritoneal cytology showed significant correlation with pT stage, lymphatic invasion, vascular invasion, ascites, and the investigating surgeon. We found the positive rate to be 2.1% for surgeon A, 10.2% for surgeon B, and 20.6% for surgeon C (P=0.024). Multivariate analysis identified pT stage, ascites, and the investigating surgeon to be significant risk factors for positive peritoneal cytology.

CONCLUSIONS

The peritoneal lavage cytology results were significantly affected by the investigating surgeon, providing strong evidence of test execution variation that could be related to poor diagnostic accuracy and stage migration in patients with advanced gastric cancer.

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.

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.

Flow cytometric quantification of intraperitoneal free tumor cells in patients with peritoneal metastasis

BACKGROUND

Peritoneal metastasis (PM) is the most life-threatening type of metastasis in abdominal malignancy. To improve the diagnostic accuracy of cytologic detection (CY) of free tumor cells (FTC) in the peritoneal cavity, we tried to quantify the FTC to leukocyte ratio using flow cytometry in patients with peritoneal metastasis.

METHODS

Cells were recovered from ascites or peritoneal lavages from 106 patients who underwent abdominal surgery and additional 89 samples which were obtained from peritoneal catheter or access port in patients with PM (+) gastric cancer. The cells were immunostained with monoclonal antibodies to CD45 and to CD326 (EpCAM). Using flow cytometry, CD326 (+) and CD45 (+) cells were classified as either tumor cells (T) or leukocytes (L) and the T/L ratio (TLR) was calculated.

RESULTS

In 106 samples obtained by laparotomy, Median (M) of the TLR of PM (+) patients was 1.39% (0-807.87%) which was significantly higher than PM (-) patients (M=0%, 0-2.14%, P < 0.001). In PM (+) patients, 86 CY (+) samples showed higher TLR than 61 CY (-) samples (M=2.81%, 0.02-1868.44% vs. M=0%, 0-3.45%, p<0.0001). In all of the 24 patients who were monitored for TLR before and after intraperitoneal (IP) chemotherapy, the TLR was reduced which was more dramatic than the results of the change in cytology.

CONCLUSIONS

TLR measured with FACS is an excellent reflection of the tumor spread in the peritoneal cavity and could be a reliable diagnostic biomarker to determine the severity of PM as well as effectiveness of IP chemotherapy.

An isolation technique to prevent the spread of tumor cells during radical gastrectomy for gastric carcinoma located on the anterior wall of the gastric antrum

OBJECTIVE

To report an isolation technique for reducing the spread of tumor cells during radical gastrectomy for lesions located on the anterior wall of the gastric antrum.

METHODS

The isolation technique involves using linear cutting staplers and a waterproof membrane to completely "block" and isolate the area to be resected. Blood samples from the portal vein and peritoneal wash samples were obtained immediately after laparotomy and during surgical resection. RT-PCR was used to determine levels of carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20). Carbon nanoparticles were injected into the subserosa of the blocked region before resection to determine lymph flow out of the region.

RESULTS

A total of 76 patients (median age, 59 years; range, 22-73 years), with tumors on the anterior wall of the gastric antrum were included (blocking group, n = 40; non-blocking group, n = 36). In the blocking group, the carbon nanoparticles did not flow beyond the blocking line. There were no significant differences between the groups in CEA or CK20 mRNA levels in portal vein blood or peritoneal wash fluid immediately after laparotomy. CEA and CK20 levels were significantly lower in portal vein blood in the blocking group during tumor resection. During a median follow-up of 30 months, the incidence of metastasis or recurrence in the blocking group was lower than the non-blocking group, although it did not reach statistical significance (17.9% vs. 25.0%, respectively).

CONCLUSION

The blocking technique can reduce hematogenous and lymphatic spread of tumor cells into the systemic circulation, and may prevent metastasis or recurrence after radical gastrectomy for gastric carcinoma.

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.

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.

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.

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.