Free Cancer Cells Research Articles

Effect of hyperthermic CO2-treated dendritic cell-derived exosomes on the human gastric cancer AGS cell line.

The aim of the present study was to determine the antitumor effects of hyperthermic CO2 (HT-CO2)-treated dendritic cell (DC)-derived exosomes (Dex) on human gastric cancer AGS cells. Mouse-derived DCs were incubated in HT-CO2 at 43°C for 4 h. The exosomes in the cell culture supernatant were then isolated. Cell proliferation was analyzed using the cell counting kit-8 (CCK-8) assay. Cell apoptosis was observed using flow cytometry, Hoechst 33258 staining and the analysis of caspase-3 activity. In addition, the proliferation of tumor cells was evaluated in xenotransplant nude mice. HT-CO2 markedly inhibited cell proliferation, as assessed by the CCK-8 assay, and also induced apoptosis in a time-dependent manner, as demonstrated by Annexin V/propidium iodide flow cytometry, caspase-3 activity and morphological analysis using Hoechst fluorescent dye. It was also revealed that HT-CO2-treated Dex decreased the expression of heat shock protein 70 and inhibited tumor growth in nude mice. In conclusion, HT-CO2 exerted an efficacious immune-enhancing effect on DCs. These findings may provide a novel strategy for the elimination of free cancer cells during laparoscopic resection. However, the potential cellular mechanisms underlying this process require further investigation.

Analysis Of Risk Factors Of Positive Peritoneal Cytology In Patients Treated For Gastric Cancer--Preliminary Report.

Presence of free gastric cancer cells in the peritoneal cavity of patients who underwent surgical treatment for gastric cancer is a negative prognostic factor and caused rapid disease recurrence, manifested as peritoneal metastases. Positive peritoneal cytology despite lack of visible peritoneal metastases was regarded as M1 class in the TNM classification (7th edition) in 2010. The aim of the study was to analyze factors associated with positive peritoneal cytology and identify groups of patients in whom diagnostic laparoscopy plus peritoneal lavage in the diagnostic process could affect therapeutic decisions. The study enrolled patients with gastric cancer who underwent surgical treatment at the Department of Surgery, Wielkopolskie Oncology Center in Poznań. During the laparotomy, after opening of the peritoneal cavity, 200 ml of physiological saline at 37 °C was administered in the tumor region. After this fluid was mixed, 100 ml of lavage fluid was collected. This fluid was subsequently spun many times to obtain sediment for cytology and immunohistochemistry investigation using anti-BerEp-4, CK 7/20, and B72.3. Results of peritoneal cytology were analyzed jointly with clinical factors--patient's age, sex and pathology factors--tumor invasion, involvement of lymph nodes, histological grade, histological type according to Lauren and localization of the cancer in the stomach. Analysis of the peritoneal fluid for presence of free cancer cells was done in 51 patients. Positive peritoneal cytology was found in 12 (23.5%) patients. In the group of patients with positive cytology, all patients had T3/T4 tumors and all were found to have lymph node metastases, while G3 cancer was found in 83.3% of patients. In patients with positive cytology, diffuse gastric cancer according to Lauren predominated (9 of 12 patients, 75%), while in patients with negative cytology--intestinal type (20 of 39 patients, 51.2%). In the group of patients with positive histology, the whole stomach was involved by the cancer process in 7 of 12 patients (58.3%), while in the group with negative histology, in 29 of 39 patients the tumor was located in the gastric body and prepyloric part (74.4%). Based on this study we can conclude that determinants of positive peritoneal cytology include: tumor stage T3/T4, N+, G3, cancer located in the whole stomach, diffuse histological type according to Lauren.

Detection methods and clinical significance of free peritoneal tumor cells found during colorectal cancer surgery.

Peritoneal washing is now part of the standard clinical practice in several abdominal and pelvic neoplasias. However, in colorectal cancer surgery, intra-peritoneal free cancer cells (IFCC) presence is not routinely investigated and their prognostic meaning is still unclear. When peritoneal washing results are positive for the presence of IFCC a worse outcome is usually expected in these colorectal cancer operated patients, but it what is not clear is whether it is associated with an increased risk of local recurrence. It is authors' belief that one of the main reasons why IFCC are not researched as integral part of the routine staging system for colon cancer is that there still isn't a diagnostic or detection method with enough sensibility and specificity. However, the potential clinical implications of a routine research for the presence IFCC in colon neoplasias are enormous: not only to obtain a more accurate clinical staging but also to offer different therapy protocols, based on the presence of IFCC. Based on this, adjuvant chemotherapy could be offered to those patients found to be positive for IFCC; also, protocols of proactive intraperitoneal chemotherapy could be applied. Although presence of IFCC appears to have a valid prognostic significance, further studies are needed to standardize detection and examination procedures, to determine if there are and which are the stages more likely to benefit from routine search for IFCC.

Bursectomy at radical gastrectomy.

Radical gastrectomy with extended lymph node dissection and prophylactic resection of the omentum, peritoneum over the posterior lesser sac, pancreas and/or spleen was advocated at the beginning of the 1960s in Japan. In time, prophylactic routine resections of the pancreas and/or spleen were abandoned because of the high incidence of postoperative complications. However, omentectomy and bursectomy continued to be standard parts of traditional radical gastrectomy. The bursa omentalis was thought to be a natural barrier against invasion of cancer cells into the posterior part of the stomach. The theoretical rationale for bursectomy was to reduce the risk of peritoneal recurrences by eliminating the peritoneum over the lesser sac, which might include free cancer cells or micrometastases. Over time, the indication for bursectomy was gradually reduced to only patients with posterior gastric wall tumors penetrating the serosa. Despite its theoretical advantages, its benefit for recurrence or survival has not been proven yet. The possible reasons for this inconsistency are discussed in this review. In conclusion, the value of bursectomy in the treatment of gastric cancer is still under debate and large-scale randomized studies are necessary. Until clear evidence of patient benefit is obtained, its routine use cannot be recommended.

Mechanisms of the Formation of Peritoneal Surface Malignancy on Omental Milky Spots from Low Grade Appendiceal Mucinous Carcinoma

Mechanisms of the Formation of Peritoneal Surface Malignancy on Omental Milky Spots from Low Grade Appendiceal Mucinous Carcinoma Purpose: Omental milky spot (OMS) is considered to have an important role in the formation of peritoneal surface malignancy (PSM). However, human OMS and cancer metastasis has not been fully clarified. The present study demonstrates the mechanisms of the formation of metastasis on the omental milky spots (OMS) from the low grade AMC. Methods and materials: To clarify the mechanism of the formation of peritoneal metastasis in low grade appendiceal mucinous carcinoma (AMC), 195 low grade AMC showing peritoneal cancer index (PCI) of ≤28 were studied for the distribution of peritoneal metastasis. Peritoneum was resected from 10 patients, and was prepared as whole-mount extending specimen. The specimens were studied by 5’-nucleotidase and alkaline phosphatase double stain and immunohistologic staining by D2-40, anti-CD31 and anti- Ki-67 monoclonal antibody. Furthermore, peritoneal parts were observed by scanning electron microscopy. Results: Pelvic and subdiaphragmatic peritoneum were involved in 164 (84%) and 143 (73%) patients. Greater omentum was involved in 135 (69%) patients. Under the SEM observation, no typical milky spots were observed on the peritoneum except for the greater omentum. Surface of OMS was covered with cuboidal mesothelial cells. Between the cuboidal mesothelial cells, many stomata were found. After digestion of OMS by 6N KOH, disk-like peritoneal pouch was detected at OMS. Small holes were found on the collagen plate covered on the bottom of the pouch. Below the pouch, initial lymphatic vessels closed to the pouch with stomata. Agglomerated blood capillaries distributed around the initial lymphatics. Metastasis foci were found around the stomata on OMS, but were not detected on the flat mesothelial cells on the greater omentum.. Conclusion: Peritoneal free cancer cells from low grade AMC may be adsorbed at stomata and adhere on the OMS. Then, they proliferate on OMS.

Clinical significance of zinc-finger E-box binding homeobox 1 mRNA levels in peritoneal washing for gastric cancer.

Zinc-finger E-box binding homeobox 1 (ZEB1) is an important regulator of epithelial-to-mesenchymal transition and is associated with various types of metastasis. Gastric cancer patients often develop peritoneal carcinomatosis, of which the detection of free cancer cells in the peritoneal washes is an important predictor. We analyzed the correlation of ZEB1 mRNA levels in the peritoneal washing (pZEB1) with clinicopathological variables and survival in 107 gastric cancer patients who underwent surgery and peritoneal washing cytology. Reverse transcription-polymerase chain reaction was performed to quantify pZEB1. The patients were classified into the pZEB1High (n=27) and the pZEB1Low (n=80) groups based on their pZEB1 expression. pZEB1 was statistically correlated with pathological T stage (P=0.03) and vascular involvement (P=0.03). At 5 years, the disease-specific survival was 36.4% for the pZEB1High group and 64.7% for the pZEB1Low group (P=0.02), whereas the disease-free survival rate was 46.9% for the pZEB1High group and 83.0% for the pZEB1Low group (P=0.03). When subclassified into 4 categories based on washing cytology and pZEB1, survival was significantly lower in the pZEB1High compared to the pZEB1Low group (cytology -negative group, P=0.01; cytology -positive group, P=0.13). Therefore, pZEB1 may add valuable information to conventional peritoneal washing cytology as a prognostic determinant in gastric cancer.

Incidence and prognostic significance of positive peritoneal lavage in colorectal cancer.

The significance of peritoneal lavage cytology as a prognostic marker has been examined in various types of cancer. However, the meaning of positive peritoneal lavage cytology in colorectal cancer is still controversial. The aim of this review is to evaluate the prognostic significance of positive peritoneal lavage cytology in colorectal cancer. An English literature search was performed on all studies published between 1998 and 2014 that compared the detection of peritoneal free cancer cells with survival or recurrence. Eighteen articles met the inclusion criteria. All studies employed one (or more) of the three techniques used to detect free cancer cells in the peritoneal cavity: (1) conventional cytology, (2) immunocytochemistry or (3) polymerase chain reaction. The incidence of positive peritoneal lavage cytology ranged from 2.2 to 47.2% across the studies. The factors correlated with positive peritoneal lavage cytology were tumor penetration and metastases (lymph node, liver and peritoneum). In nine studies, positive lavage findings were associated with a worse survival, and it was associated with increased recurrence in 13 studies. Positive peritoneal lavage cytology seems to be an indicator of a poor prognosis in colorectal cancer patients. Further studies are needed to clarify the prognostic impact of peritoneal lavage cytology, by comparing the different methods used for the collection of the peritoneal lavage.

426. Incidence of free colorectal cancer cells in peritoneal cavity and correlation with clinicopathologic variables: An analysis of 275 patients undergoing curative intent resection for colorectal cancer

Background: This study was conducted to investigate the incidence of free cancer cells in the peritoneal lavage cytology of patients who had undergone curative resection for colorectal cancer.

Abstract 4726: Virus-guided fluorescence imaging of intraperitoneal free gastric cancer cells as a potential clinical biomarker

Abstract Peritoneal dissemination is a common pattern of metastasis in patients with gastric cancer, and associated with worse prognosis. Peritoneal lavage cytology during the operation is an important factor in predicting future development of peritoneal metastasis and determining the treatment strategy, but its sensitivity and specificity are unsatisfactory. TelomeScan is an adenovirus engineered to replicate and express GFP only in telomerase-activating tumor cells, so that we can easily detect viable cancer cells even among numerous normal cells. We hypothesized that TelomeScan might be applicable to detecting free cancer cells in peritoneal wash. Methods: Peritoneal washes were obtained from 42 gastric cancer patients during operation. The number of GFP-positive cells was determined for each sample and compared with cytology results and clinicopathological data Results: Clinical stage was ranged from IA to IV, and thirteen cases were diagnosed as class IV or class V by peritoneal lavage cytology. More than 10 GFP-positive cells were detected in 12 out of 42 cases, and these cases showed a worse prognosis when compared to the other 30 cases. Conclusion: We were able to detect gastric cancer cells as GFP-positive cells in peritoneal wash using TelomeScan. Furthermore, the presence of GFP-positive cells in peritoneal wash was associated with worse prognosis. These results suggest that number of cancer cells detected by TelomeScan in the peritoneal wash may have important clinical implication as prognostic and therapeutic biomarkers in gastric cancer. Citation Format: Megumi Watanabe, Shunsuke Kagawa, Michihiro Ishida, Naoto Hori, Satoru Kikuchi, Shinji Kuroda, Hiroyuki Kishimoto, Masahiko Nishizaki, Hiroshi Tazawa, Toshiyoshi Fujiwara. Virus-guided fluorescence imaging of intraperitoneal free gastric cancer cells as a potential clinical biomarker. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4726. doi:10.1158/1538-7445.AM2014-4726

The role of the CCL22-CCR4 axis in the metastasis of gastric cancer cells into omental milky spots.

BackgroundThe omentum is one of the initial sites for peritoneal metastasis because it possesses milky spots that provide a microenvironment for cancer cells to readily migrate and grow into micrometastases. This study investigated the role of the CCL22-CCR4 axis in gastric cancer cells selectively infiltrating into milky spots.MethodsGastric cancer MFC cells labelled with DiI were injected intraperitoneally into strain 615 mice. The mice were euthanised at specified intervals and the omentum was excised for immunohistochemistry. The effects of CCL22 on the proliferation and migration of MFCs were assessed by MTT and trans-well assays. RT-PCR and Western blot analysis detected CCR4 mRNA and protein expression levels in MFCs. Immunohistochemistry was used to analyse CCL22 and CCR4 expression in the milky spot micrometastases.ResultsTwo weeks after intraperitoneal injection, the milky spot areas were completely occupied by proliferating gastric cancer cells and cell cluster-type micrometastases were observed. In contrast, cancer cells formed single cell-type micrometastases in the non-milky spot areas. MFCs expressed CCR4, which was localised on the cell surface and or in the cytoplasm. Different concentrations of CCL22 significantly increased the proliferation ability of MFCs. Additionally, concentrations of CCL22 between 10–100 ng/ml significantly increased the migration of MFCs. Within omental milky spots, CCL22 was localised mainly on the cell surface and or in the cytoplasm. Within sections of omental milky spot micrometastases, CCR4 was recognised on or in gastric cancer cells, constituent cells milky spots, blood cells and blood endothelial cells.ConclusionsOmental milky spots are a congenial microenvironment for peritoneal free gastric cancer cells to migrate, survive, and establish cell cluster-type metastases. The CCL22-CCR4 axis contributes to this selective infiltration process.

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.

Intraoperative dissemination during gastrectomy for gastric cancer associated with serosal invasion.

Free cancer cells shed from the serosal surface of gastric cancer result in peritoneal dissemination. The aim of this study was to clarify the extent of tumor cell implantation due to surgical manipulation during gastrectomy. The participants comprised 34 patients who underwent curative gastrectomy for gastric cancer with macroscopic serosal invasion. Two types of cytology were obtained from each patient: (1) cytology from the wound dressing material that covered the serosal invasion area during the operation (Covering Cy), and (2) cytology of the intraperitoneal wash samples (Lavage Cy). Thirteen patients showed no serosal invasion histopathologically, and all of these patients had negative results for both Lavage Cy and Covering Cy. Among the 21 patients with histopathologically confirmed serosal invasion, six had positive results for both Lavage Cy and Covering Cy, three showed positive findings for Covering Cy alone, one had positive Lavage Cy alone and 11 patients had negative results for both Lavage Cy and Covering Cy. Disseminated recurrence developed in 10 patients. Seven of the nine patients with positive Covering Cy developed disseminated recurrence, compared to three of 12 patients with negative Covering Cy. Positive Covering Cy findings were significantly associated with disseminated recurrence (p<0.05). We demonstrated that the intraoperative dissemination of gastric cancer can occur during gastrectomy.

The clinical significance of potentially curative resection for gastric cancer following the clearance of free cancer cells in the peritoneal cavity by induction chemotherapy.

The aim of this study was to evaluate the significance of the conversion of the peritoneal cytology from positive to negative following induction chemotherapy in relation to the prognosis after subsequent resection for gastric cancer. This retrospective study was conducted using a prospectively maintained database. A total of 47 patients with free cancer cells in the peritoneal cavity, as evaluated by staging laparoscopy, but no other evidence of distant metastasis, who underwent induction chemotherapy followed by surgery were enrolled in the study. Then, the clinicopathological factors and survival in the study subjects were assessed. The median survival time and 5-year overall survival rate of the 47 study participants were 20.4 months and 25.0 %, respectively. In 23 of the patients, the peritoneal cytology converted from positive to negative after the induction chemotherapy, and a microscopically margin-negative gastrectomy was performed. The median survival time of 30.4 months and the 5-year survival rate of 34.6 % of these patients was significantly more favorable than the corresponding values of 15.0 months and 17.6 % in the patients who had persistently positive cytology (P = 0.03). Based on our findings, the clearance of free cancer cells in the peritoneal cavity by induction chemotherapy improves the prognosis of patients following subsequent gastrectomy.

Cellular source of peritoneal free cancer cells during a reconstructive surgery after gastrectomy for gastric cancer.

e15063 Background: We have recently shown that viable cancer cells spilled into peritoneal cavity during curative gastric cancer (GC) surgery more frequently in cases with advanced tumor invasion a...

GASTRICHIP: D2 resection and hyperthermic intraperitoneal chemotherapy in locally advanced gastric carcinoma: a randomized and multicenter phase III study

BackgroundIn Europe, gastric cancer remains diagnosed at advanced stage (serosal and/or lymph node involvement). Despite curative management combining perioperative systemic chemotherapy and gastrectomy with D1-D2 lymph node dissection, 5-year survival rates of T3 and/or N + patients remain under 30%. More than 50% of recurrences are peritoneal and/or locoregional. The use of adjuvant hyperthermic intraperitoneal chemotherapy that eliminates free cancer cells that can be released into peritoneal cavity during the gastrectomy and prevents peritoneal carcinomatosis recurrences, was extensively evaluated by several randomized trials conducted in Asia. Two meta-analysis reported that adjuvant hyperthermic intraperitoneal chemotherapy significantly reduces the peritoneal recurrences and significantly improves the overall survival. As it was previously done for the evaluation of the extension of lymph node dissection, it seems very important to validate on European or caucasian patients the results observed in trials performed in Asia.Methods/designGASTRICHIP is a prospective, open, randomized multicenter phase III clinical study with two arms that aims to evaluate the effects of hyperthermic intraperitoneal chemotherapy with oxaliplatin on patients with gastric cancer involving the serosa and/or lymph node involvement and/or with positive cytology at peritoneal washing, treated with perioperative systemic chemotherapy and D1-D2 curative gastrectomy. Peroperatively, at the end of curative surgery, patients will be randomized after preoperatively written consent has been given for participation. Primary endpoint will be overall survival from the date of surgery to the date of death or to the end of follow-up (5 years). Secondary endpoint will be 3- and 5-year recurrence-free survival, site of recurrence, morbidity, and quality of life. An ancillary study will compare the incidence of positive peritoneal cytology pre- and post-gastrectomy in two arms of the study, and assess its impact on 5-year survival. The number of patients to be randomized was calculated to be 306.Trial registrationEudraCT number: 2012-005748-12, ClinicalTrials.gov identifier: NCT01882933.

Intraoperative peritoneal lavage: limitations of current evidence for clinical implementation.

Peritoneal recurrence after a curative resection of colorectal cancer is less common than lymphatic spread or hematogenous metastasis [1]. Moreover, peritoneal carcinomatosis often develops at a later stage of recurrent disease and is regarded as noncurable. Therefore, being able to predict the possibility of peritoneal recurrence at an early time after the original diagnosis and to prevent its occurrence would be a great advance in treating colorectal cancer [2]. Positive peritoneal lavage is a well-known risk factor for local/peritoneal recurrence in patients with colorectal cancer and various other types of cancers. Among gastrointestinal malignancies, the significance of peritoneal cytology has been extensively studied in gastric cancer. The existence of free cancer cells at intraoperative peritoneal lavage has been reported to be one of the most accurate prognostic factors for gastric cancer and is now classified as Stage IV [3, 4]. Besides gastric cancer, the examination of peritoneal free cancer cell is an important staging step in pancreatic, ovarian and endometrial cancer [5] Although positive peritoneal lavage is an established poor prognostic factor in colorectal cancer that has been proven in many studies, including several systemic reviews and meta-analyses [3, 6, 7], examining the peritoneal cytology is still not a standard procedure for staging colorectal cancer. To be a reliable clinical indicator, future studies have to overcome several issues involving peritoneal lavage. The first is the differences in the methods of lavage and free cell detection. Proper timing of lavage is controversial. Some studies performed lavage immediately after the opening of the abdominal wall and some so did after the tumor resection [7]. Most of these studies used a 0.9% NaCl solution as the lavage fluid, but the volume and the temperature of the solution were different from study to study. Most importantly, the methods for detecting free cancer cells varied and included conventional cytology, quantitative methylation specific polymerase chain reaction (PCR), immunological, immunobead quantitative PCR, radioimmunoassay or immunoperoxidase assay [8, 9, 10, 11, 12] methods. The staining technique was also different among the previous studies. These differences among the studies might result in a very wide range of positive peritoneal lavage ranging from 2.1% to 52%, and this wide range makes selecting a high-risk group for local/peritoneal recurrence based on peritoneal lavage difficult. Secondly, a well-designed comparative study is insufficient for recommending positive peritoneal cytology as a clinical indicator on which practical decisions can be based. A recent prospective study showed an improvement in peritoneal recurrence and overall survival in patients with positive lavage who underwent intraperitoneal chemotherapy with mitomycin C compared to those who did not [1, 13]. Because positive peritoneal lavage is associated with a worse prognosis, a potential benefit of peritoneal lavage may exist for the identification of patients to receive adjuvant treatment. Further studies are needed to examine whether adjuvant treatment can improve the oncologic results of patients with positive peritoneal lavage.

Intra-operative peritoneal lavage for colorectal cancer.

Free cancer cells can be detected in peritoneal fluid at the time of colorectal surgery. Peritoneal lavage in colorectal surgery for cancer is not used in routine, and the prognostic significance of intraperitoneal free cancer cells (IPCC) remains unclear. Data concerning the technique of peritoneal lavage to detect IPCC and its timing regarding colorectal resection are scarce. However, positive IPCC might be the first step of peritoneal spread in colorectal cancers, which could lead to early specific treatments. Because of the important heterogeneity of IPCC determination in reported studies, no treatment have been proposed to patients with positive IPCC. Herein, we provide an overview of IPCC detection and its impact on recurrence and survival, and we suggest further multi-institutional studies to evaluate new treatment strategies.

Free Cancer Cells Detection in Surgical Field Washings of Breast Cancer

Free cancer cells in the surgical field might be one of the causation of local recurrence in breast cancer patients who underwent mastectomy. The goal of the study was to provide a theoretical basis for killing or removing of the free cancer cells in the surgical field. Cytological examination of surgical field washings was performed in 148 patients with breast cancer. The results and pathological stages were compared and analyzed. Free cancer cells were found in the surgical field washings in 54 cases. The total positive rate of cytology was 37.8% (54/143). There was a significant relationship between the pathological stage, tumor size, axillary lymph node metastases and the positive rate of cytology, but no association with operation type was observed. Stage I, II and III showed a positive rate of 8.6%, 33.8% and 85.7%. The positive rate of T1, T2 and T3 plus T4 were 16.0%, 33.8% and 77.4%, respectively. When the number of axillary metastatic lymph nodes was over three, the positive rate of free cancer cells was 87.0% and only 20.1% if no axillary lymph node metastasis. Our study results suggested that killing or removing of the free cancer cells in the surgical field of breast cancer might be necessary during the operation.

Intraluminal exfoliated cancer cells and effectiveness of bowel ligatures during sigmoidectomy for sigmoid colon cancer

To establish the efficiency of bowel ligatures in colon cancer surgery, focusing on the extent to which exfoliated cancer cells are shed in the colonic lumen during sigmoidectomy. Twenty consecutive patients who underwent sigmoidectomy for sigmoid colon cancer were prospectively randomized into two groups: the "ligatures group", in which bowel ligatures were placed, 3, 5, 10 cm from the tumor proximally and distally before dissection; and the "no ligatures group", in which the corresponding sites were ligated only immediately before taking the specimen out. Each colonic segment ligated was irrigated with saline and samples were sent for blind cytological examination. Cancer cells were found in the colonic segment where the tumor was located, in 18 of 20 samples. The frequency of free cancer cells decreased from 50 to 0 % (p < 0.04) in the distal 3-5 cm colonic segment and from 80 to 20 % (p < 0.03) in the proximal colonic segment after performing bowel ligatures. Free cancer cells were confirmed in 1 of 10 samples at both colonic segments 5-10 cm from the tumor, even after bowel ligatures. Intraluminal exfoliated cancer cells could be eliminated by placing bowel ligatures during sigmoidectomy. Measures should be considered to eliminate exfoliated cancer cells during colectomy, even after placing bowel ligatures.

Prediction of peritoneal recurrence by the mRNA level of CEA and MMP-7 in peritoneal lavage of gastric cancer patients

A number of tumor markers had been reported to be useful in detecting free cancer cells in the peritoneal cavity and predict peritoneal recurrence in gastric cancer patients. The objective of this study was to compare the clinical impact of different tumor markers in peritoneal lavage fluid using the real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) technique and to screen the most effective ones from them. The peritoneal lavage fluid of 116 patients with gastric cancer was sampled at laparotomy. After RNA extraction and reverse transcription, real-time quantitative polymerase chain reaction (PCR) was performed using the primers and probes for carcinoembryonic antigen (CEA), cytokeratin-20, matrix metalloproteinase-7 (MMP-7), carbohydrate antigen 125, and transforming growth factor-beta-1. Among the 116 patients, 45 (38.8%) were confirmed to have peritoneal recurrence. Any of the PCR-positive results of the five tumor markers could predict peritoneal recurrence in the univariate analysis (P < 0.001). In the multivariate analysis, the PCR results of CEA (P = 0.003) and MMP-7 (P = 0.028) were found to be independent prognostic factors. A real-time quantitative RT-PCR analysis of the CEA and MMP-7 transcripts in peritoneal lavage fluid could effectively predict peritoneal recurrence in advanced gastric cancer patients who underwent a potentially curative resection.