Prognostic significance of intraperitoneal cancer cells in gastric carcinoma: analysis of real time reverse transcriptase-polymerase chain reaction after 5 years of followup

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.

Prognostic Significance of Intraoperative Peritoneal Lavage Cytology in Patients with Pancreatic Ductal Adenocarcinoma: A Single-Center Experience and Systematic Review of the Literature

BACKGROUND

The prognostic significance of peritoneal lavage cytology (PLC) in patients with pancreatic ductal adenocarcinoma (PDAC) remains controversial. The purpose of this study was to evaluate the prognostic impact of PLC status in PDAC patients.

METHODS

Patients intending to undergo resection for PDAC between 2007 and 2020 were included. Survival was compared among patients who underwent resection with negative or positive PLC status and those who did not undergo resection. Univariable and multivariable analyses were conducted to evaluate the prognostic impact of positive PLC status. A systematic literature review was performed to evaluate the correlation between prognosis and the positive PLC rate.

RESULTS

A total of 480 patients formed the study cohort and were divided as follows: 438 in the negative PLC group, 18 in the positive PLC group, and 24 in the no resection group. Although the median survival time significantly differed between the negative and positive PLC groups (35.7 vs. 13.6 months, P < 0.001), it did not significantly differ between the positive PLC and no resection groups (13.6 vs. 12.2 months, P = 0.605). Multivariable analyses demonstrated that positive PLC status (hazard ratio = 3.54, 95% confidence interval = 1.97-6.38, P < 0.001) was the strongest poor prognostic factor. Based on statistical analyses for the systematic review, the prognostic impact of positive PLC status weakened significantly as the institutional positive PLC rate increased (P = 0.044).

CONCLUSIONS

Resection did not improve the prognosis of patients with positive PLC status in our cohort. The institutional positive PLC rate may be a good reference for surgical indication in these patients.

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.

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.

Surgery with curative intent for stage IV gastric cancer: Is it a reality of illusion?

Gastric cancer with metastases outside of the regional lymph nodes is deemed oncologically unresectable. Nevertheless, some metastatic lesions are technically resectable by applying established surgical techniques such as para-aortic lymphadenectomy and hepatectomy. At the time of compilation of the Japanese gastric cancer treatment guidelines version 4, systematic reviews were conducted to see whether it is feasible to make any recommendation to dissect both the primary and metastatic lesions with intent to cure, possibly as part of multimodality treatment. Long-term survivors were found among carefully selected groups of patients both in prospective and retrospective studies. In addition, there is a growing list of publications reporting encouraging outcomes of gastrectomy conducted after exceptionally good response to chemotherapy, usually among patients who underwent R0 resection. This type of surgery is often referred to as conversion surgery. It is sometimes difficult to define a clear borderline between curative surgery scheduled after neoadjuvant chemotherapy and the conversion surgery. This review summarizes what we knew after the literature reviews conducted at the time of compiling the Japanese guidelines and in addition reflects some new findings obtained thereafter through clinical trials and retrospective studies. Metastases were divided into three categories based on the major metastatic pathways: lymphatic, hematogenous, and peritoneal. In each of these categories, there were findings that could provide hope for patients with metastatic disease. These findings implied that the surgical technique that we already use could become more useful upon further developments in antineoplastic agents and drug delivery.

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.

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.

Molecular mechanisms of peritoneal dissemination in gastric cancer

Peritoneal dissemination represents a devastating form of gastric cancer (GC) progression with a dismal prognosis. There is no effective therapy for this condition. The 5-year survival rate of patients with peritoneal dissemination is 2%, even including patients with only microscopic free cancer cells without macroscopic peritoneal nodules. The mechanism of peritoneal dissemination of GC involves several steps: detachment of cancer cells from the primary tumor, survival in the free abdominal cavity, attachment to the distant peritoneum, invasion into the subperitoneal space and proliferation with angiogenesis. These steps are not mutually exclusive, and combinations of different molecular mechanisms can occur in each process of peritoneal dissemination. A comprehensive understanding of the molecular events involved in peritoneal dissemination is important and should be systematically pursued. It is crucial to identify novel strategies for the prevention of this condition and for identification of markers of prognosis and the development of molecular-targeted therapies. In this review, we provide an overview of recently published articles addressing the molecular mechanisms of peritoneal dissemination of GC to provide an update on what is currently known in this field and to propose novel promising candidates for use in diagnosis and as therapeutic targets.

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.

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.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A systematic review and meta-analysis of gastric cancer treatment in patients with positive peritoneal cytology

Gastric cancer patients with positive peritoneal cytology as the only marker of metastatic disease have poor prognoses. There is no universal consensus on the most appropriate treatment regimen for this particular patient group. We reviewed and analyzed published data to determine the optimal treatment regimen for patients with peritoneal cytology-positive gastric adenocarcinomas. Six electronic databases were explored [PubMed, Cochrane (Systematic Reviews and Controlled Trials), PROSPERO, DARE, and EMBASE]. The primary outcome was overall survival with secondary outcomes including patterns of recurrence and treatment-related morbidity. Six studies were included for data extraction. There was no significant heterogeneity between studies. The use of S1 monotherapy was associated with a significant survival benefit (HR 0.48; 95% CI 0.32-0.70; p = 0.0002). Intraoperative intraperitoneal chemotherapy (IIPC) with adjuvant chemotherapy showed a trend toward improvement in overall survival (HR 0.70; 9 % CI 0.47-1.04; p = 0.08). A recent randomized controlled trial examining extensive intraperitoneal lavage (EIPL) with IIPC showed a significant improvement in overall survival (5-year overall survival, 43.8% for EIPL-IPC group compared with 4.6% for IPC group). However, these promising results need to be validated in larger prospective randomized trials.

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

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

Diagnostic 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.

The trifunctional antibody catumaxomab amplifies and shapes tumor-specific immunity when applied to gastric cancer patients in the adjuvant setting

BACKGROUND

Patients with gastric cancer benefit from perioperative chemotherapy, however, treatment is toxic and many patients will relapse. The trifunctional antibody catumaxomab targets EpCAM on tumor cells, CD3 on T cells, and the Fcγ-receptor of antigen-presenting cells. While in Europe catumaxomab is approved for treating malignant ascites, it has not been investigated in the perioperative setting and its exact immunological mode of action is unclear.

METHODS

In our study, gastric cancer patients received neoadjuvant platinum-based chemotherapy, one intraoperative application of catumaxomab, and 4 postoperative doses of intraperitoneal catumaxomab. Immunomonitoring was performed in 6 patients before surgery, after completion of catumaxomab treatment, and one month later.

RESULTS

Intraperitoneal application of catumaxomab caused an increased expression of activation markers on the patients' T cells. This was accompanied by a transient decrease in numbers of CXCR3(+) effector T cells with a T-helper (Th)-1 phenotype in the peripheral blood. All patients evidenced pre-existing EpCAM-specific CD4(+) and/or CD8(+) T cells. While these cells transiently disappeared from the blood stream after intraperitoneal application of catumaxomab, we detected increased numbers of peripheral EpCAM-specific cells and a modified EpCAM-specific T-cell repertoire 4 weeks after completion of treatment. Finally, catumaxomab also amplified humoral immunity to tumor antigens other than EpCAM.

CONCLUSIONS

Our findings suggest that catumaxomab exerts its clinical effects by (1) activating peripheral T cells, (2) redistributing effector T cells from the blood into peripheral tissues, (3) expanding and shaping of the pre-existing EpCAM-specific T-cell repertoire, and (4) spreading of anti-tumor immunity to different tumor antigens.

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.

The detection of gastric cancer cells in intraoperative peritoneal lavage using the reverse transcription--loop-mediated isothermal amplification method

INTRODUCTION

To detect a small number of malignant cells, we used a highly sensitive detection system that measures the expression levels of cytokeratin (CK) 19 messenger RNA by reverse transcription-loop-mediated isothermal amplification (RT-LAMP).

MATERIALS AND METHODS

We evaluated the clinical relevance of our novel diagnostic method with an RT-LAMP assay using CK19 as a target gene for the detection of free cancer cells in peritoneal lavage and assessed the clinical significance of the molecular diagnosis by survival analysis and frequency of recurrence, with a median follow-up period of 39 mo. We observed 52 patients with gastric cancer who underwent gastrectomy, bypass operation, and exploratory laparotomy.

RESULTS

Those 52 patients, who were subjected to both RT-LAMP and cytologic examination, were divided into the following three groups: (1) patients positive by cytology and RT-LAMP (CY+/LAMP+) (n = 9), (2) patients positive by LAMP and negative by cytology (CY-/LAMP+) (n = 12), and (3) patients negative by both cytology and LAMP (CY-/LAMP-) (n = 31). All patients with simultaneous peritoneal dissemination and positive cytology were positive on RT-LAMP. The results of RT-LAMP were statistically significant for recurrence by univariate analysis (P < 0.005). Cytology-positive cases had a very poor prognosis, and RT-LAMP-positive cases had a worse prognosis than RT-LAMP-negative cases.

CONCLUSIONS

Our findings suggest that CK19 RT-LAMP would be useful as an intraoperative diagnostic modality to detect patients with a high risk of recurrence even after clinically curative surgery, who thus require proper adjuvant therapy.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Comparison of laparoscopic and open gastrectomy on cancer cells exfoliating from the cancer-invaded serosa

BACKGROUND

Whether laparoscopic gastrectomy may reduce the frequency of gastric cancer cells exfoliating from the cancer-invaded serosa remains unclear. This study aimed to compare the detection of free gastric cancer cells in the peritoneal cavity during laparoscopic and open gastrectomy.

METHODS

Intraoperative peritoneal washings were collected from 63 gastric cancer patients undergoing laparoscopic gastrectomy and 61 patients undergoing open surgery. Hematoxylin and eosin staining and real time reverse transcription-polymerase chain reaction were used to examine the free cancer cells.

RESULTS

The postoperative positive rates of free cancer cells detected by cytologic and real time reverse transcription-polymerase chain reaction were 39.68% and 44.26% in the laparoscopic and open groups, respectively. The depth of tumor invasion, area of invaded serosa, regional lymph node involvement, and higher tumor node metastasis staging were significantly associated with the presence of free cancer cells.

CONCLUSIONS

The laparoscopic techniques used in gastric cancer surgery were not associated with a greater risk for the intraperitoneal dissemination of cancer cells than conventional techniques.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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