Immunocytology improves prognostic impact of peritoneal tumour cell detection compared to conventional cytology in gastric cancer

Clinical Significance of Peritoneal Fluid Examination for Free Cancer Cells in Patients Qualified for Surgery for Gastric Cancer

Background: Peritoneal lavage cytology in patients with gastric cancer may correlate with an unfavorable prognosis. This study evaluated the presence of free cancer cells in the peritoneal lavage of a population of patients with gastric cancer and its correlation with the outcome of surgical treatment.

Methods: One hundred patients diagnosed with gastric or gastrointestinal junction adenocarcinoma underwent surgery. In all patients, a cytological and immunohistochemical analysis of peritoneal lavage was performed. Based on the presence of free cancer cells (fcc) at the cytological and immunohistochemical examination of peritoneal lavage, patients undergoing surgery for gastric cancer were divided into two groups: fcc (+) and fcc (–).

Results: A total of 100 patients, 37 women, and 63 men with a median age of 65 years were included in the study. In the entire study group, 16 (16%) patients were positive for the presence of free cancer cells (fcc +) at peritoneal lavage examination. However, in the group of patients who underwent gastrectomy, fcc (+) was found in 10 out of 77 (13%) patients. The presence of cancer cells in peritoneal lavage was a strong predictive factor in an unfavorable outcome after surgery, and 1-year and 2-year patient survival was 34 and 0% in fcc (+) patients and 79 and 59% in fcc (–), respectively. Moreover, the presence of free cancer cells was associated with a five-fold increased risk of death within 2 years after surgery. When analyzing the group of patients undergoing R0/R1 surgery, this difference was even more significant (p < 0.0001).

Conclusions: The presence of free cancer cells in peritoneal lavage may significantly affect the outcome of patients with gastric cancer. Radical surgery in patients with free cancer cells in the peritoneal lavage did not result in a survival advantage. Identification of free cancer cells could help for a better stratification of gastric cancer patients, identifying those patients who could better benefit from a radical surgical treatment, finally improving long-term survival.

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.

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

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

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

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

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.

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.

Conventional cytology is not beneficial for predicting peritoneal recurrence after curative surgery for gastric cancer: results of a prospective clinical study

PURPOSE

The role of peritoneal washing cytology in determining further treatment strategies after surgery for gastric cancer remains unclear. One reason for this is the fact that optimal procedures to increase the accuracy of predicting peritoneal metastasis have not been established. The aim of this study was to evaluate the efficacy of cytology using samples harvested from two different abdominal cavity sites during gastric cancer surgery.

MATERIALS AND METHODS

We prospectively recruited 108 patients who were clinically diagnosed with locally advanced gastric cancer (higher than cT1 stage disease). Peritoneal washing fluids were collected from the pouch of Douglas and the subphrenic area. Patients were prospectively followed up for 2 years to determine the recurrence and survival rates.

RESULTS

Thirty-three patients dropped out of the study for various reasons, so 75 patients were included in the final analysis. Seven patients (9.3%) showed positive cytology findings, of whom, three showed peritoneal recurrence. Tumor size was the only factor associated with positive cytology findings (P=0.037). The accuracy and specificity of cytology for predicting peritoneal recurrence were 90.1% and 94.2%, respectively, whereas the sensitivity was 50.0%. The survival rate did not differ between patients with positive cytology findings and those with negative cytology findings (P=0.081).

CONCLUSIONS

Peritoneal washing cytology using samples harvested from two different sites in the abdominal cavity was not able to predict peritoneal recurrence or survival in gastric cancer patients. Further studies will be required to determine whether peritoneal washing cytology during gastric cancer surgery is a meaningful procedure.

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.

Prognostic significance of detection of microscopic peritoneal disease in colorectal cancer: a systematic review

BACKGROUND

Free intraperitoneal tumour cells are an independent indicator of poor prognosis, and are encorporated in current staging systems in upper gastrointestinal cancers, but not colorectal cancer. This systematic review aimed to evaluate the role and prognostic significance of positive peritoneal lavage in colorectal cancer.

METHODS

A search was undertaken of PUBMED/Medline and Cochrane databases for English language articles from 1990 to 2012 using a predefined search strategy. Both detection of free tumour cells and/or detection of tumour-associated antigens in peritoneal lavage fluid were considered a positive lavage. Primary endpoints were rates of positive lavage, recurrence and survival.

RESULTS

Of 3805 articles identified by title, 18 met inclusion criteria (n = 3197 patients, 59.5% colon, 40.5% rectal cancer). There was heterogeneity across studies in method of detection of peritoneal disease with 7 studies using more than one method (conventional cytology (14 studies), immunological techniques (6 studies), molecular techniques (4 studies)). The rate of positive lavage varied from 2.1% to 52% across studies, with a weighted mean rate of positive lavage of 13.17% overall (95% CI 12.74-13.59). In 10 studies (n = 2017) positive peritoneal lavage was associated with worse survival, and with increased recurrence in 12 (n = 2371). Clinicopathological factors frequently associated with positive lavage included macroscopic peritoneal disease, increasing tumour stage and nodal disease.

CONCLUSION

Positive peritoneal lavage is a negative prognostic factor in colorectal cancer. However, its utility in staging colorectal cancer is currently limited by wide variation in rates of positive lavage between studies due to differences in methods of peritoneal lavage fluid analysis.

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.

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

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

Can intra-operative intraperitoneal free cancer cell detection techniques identify patients at higher recurrence risk following curative colorectal cancer resection: a meta-analysis

BACKGROUND

Accurate staging of colorectal cancer is important for predicting prognosis and guiding treatment. This study uses meta-analysis to investigate if the pre- or post-resection detection of intraperitoneal free cancer cells can predict recurrence in patients undergoing curative colorectal cancer surgery.

METHODS

A literature search was performed on all studies between January 1990 and July 2007 comparing the detection of intraperitoneal free cancer cells either pre- or post-resection with prognosis in colorectal cancer. The following prognostic outcomes were meta-analyzed: overall recurrence rate and local recurrence rate. A random-effect model was used and heterogeneity was assessed.

RESULTS

Nine studies reporting on a total of 1182 subjects matched the selection criteria. Free cancer cells were detected prior to tumor resection in 125/822 (15.2%) of patients and following resection in 64/533 (12%) of patients. Preresection, the absence of tumor cells was associated with a lower overall recurrence (25.2%) compared to the presence of tumor cells [46.4%, odds ratio (OR) = 0.41, confidence interval (CI) 0.19-0.88]; as well as a significantly lower local recurrence (12.2% versus 21.1%, OR = 0.42, CI 0.21-0.82). Postresection, the absence of tumor cells also resulted in significantly lower overall recurrence (17.3%) when compared to the presence of tumor cells (52.6%, OR = 0.07, CI 0.03-0.18).

CONCLUSIONS

The detection of intraperitoneal free cancer cells is associated with higher recurrence and poorer prognosis. Use of these techniques can identify patients at higher recurrence risk. This could be particularly valuable in stage II disease to identify patients who may benefit from adjuvant chemotherapy.

Free peritoneal tumour cells are an independent prognostic factor in curatively resected stage IB gastric carcinoma

Background

Several studies have shown that the cytological detection of free peritoneal tumour cells (FPTCs) in patients with gastric cancer indicates the presence of metastatic disease. The immunocytochemical detection of FPTCs, especially in early-stage tumours, has not been examined comprehensively.

Method

Peritoneal lavage was performed in 351 patients before curative resection of a gastric carcinoma between 1987 and 2001, and an adequate sample was obtained from 346 patients. FPTCs were detected immunocytochemically using Ber-EP4 antibody. Median follow-up time was 70 months.

Results

FPTCs were detected in the lavage fluid of 74 patients (21·4 per cent) and correlated with increasing pathological tumour depth (pT) and lymph node (pN) status (P &lt; 0·001). The 5-year overall survival of patients with FPTCs was significantly worse than that of patients without FPTCs (35 versus 71·9 per cent; P &lt; 0·001). FPTCs were present in 14 (8·5 per cent) of 164 patients with stage IA or IB tumours. Although the detection of FPTCs had no prognostic significance for stage IA tumours, the presence of FPTCs in those with stage IB tumours was associated with a worse prognosis (P &lt; 0·001). Multivariate analysis identified the presence of FPTCs as an independent prognostic factor in the whole cohort and in the stage IB subgroup.

Conclusion

Detection of FPTCs is associated with poor prognosis even in patients with early-stage gastric cancer and should be used for risk-group stratification.

Minimal residual disease in gastric cancer

In curatively resected gastric cancer, the incidence of distant relapse is as high as 30%. Although the most important factor contributing to the local control of the tumor is the microscopic tumor-free margin of the surgical resection, the occurrence of distant metastases is in many cases due to preoperative or perioperative tumor cell dissemination. In addition to the established TNM staging system, disseminated tumor cells may serve as independent prognostic factors influencing patient outcome after curative surgery. Basically, in gastric cancer three compartments have been identified in which single tumor cells may be shed: lymph nodes, peritoneal cavity, and bone marrow. Assessment of resected regional lymph nodes with monoclonal antibodies directed against cytokeratin antigens leads to an upstaging in comparison with conventional histology. Nodal micrometastases detected by immunohistochemistry result in an upstaging of up to 36% of patients. However, their prognostic significance remains controversial. Local dissemination of tumor cells in the peritoneal cavity determines the outcome in advanced gastric cancer and diffuse-type carcinoma. Patients with negative peritoneal washings seem to have a more favorable prognosis. Moreover, with the use of these diagnostic tools, patient subpopulations may be identified which profit from intraperitoneal therapy regimens. Diffuse hematogenous tumor cell dissemination into the bone marrow has been shown to be a prognostic factor in several studies. In our own population of 180 gastric cancer patients, bone marrow cells were screened immunohistochemically with a monoclonal antibody directed against cytokeratin 18 (CK18). In 95 patients (53%), CK2-posititve cells were detected. In a multivariate analysis, the independence of the presence of three or more disseminated tumor cells per 10(6) mononuclear cells was proven to be a prognostic factor in patients with intestinal-type tumors, pT1/2 status, and pN0 status. In conclusion, the TNM status only partially reflects the actual extent of systemic disease in patients with resected gastric cancer. The assessment of minimal residual disease is valuable in estimating the prognosis in many patients. In the future, staging systems will have to not only include TNM data but also provide specific information on biological properties of residual cancer cells in order to establish more exact prognostic estimates and provide patients with an individually tailored multimodal treatment.