Detection of Mesenteric Tumor Using Dynamic Contrast Enhanced MRI.

PURPOSE: This study was designed to evaluate the use of a novel imaging technique, dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), for detecting mesenteric peritoneal metastases. METHODS: Thirty-four patients underwent preoperative conventional MRI, including T1, T2, diffusion-weighted (DWI), and delayed gadolinium MRI, as well as DCE MRI. DCE MRI involved imaging the peritoneal cavity every 9 s for 6 min. DCE images were processed to generate parametric maps of tumor vascularity. Two oncologic surgeons and a radiologist reviewed conventional MRI for all tumor and then later reviewed the conventional MRI plus the DCE parametric maps. Images were reviewed for tumor of the parietal peritoneum, porta hepatis, bowel serosa, upper small bowel mesentery, lower small bowel mesentery, and pelvis. Conventional MRI and DCE + MRI findings were compared to operative and histopathologic reports for tumor detection. PCI scores were calculated for surgery, MRI, and DCE. RESULTS: Upper mesenteric tumor was present in 21 patients. DCE images showed a sensitivity of 100%, specificity of 92%, and accuracy of 97% compared with conventional MRI sensitivity of 24%, specificity of 93%, and accuracy of 50% (p = 0.006). Lower mesenteric tumor was present in 22 patients. DCE images showed a sensitivity of 100%, specificity of 92%, and accuracy of 97% compared with conventional MRI sensitivity of 45%, specificity of 92%, and accuracy of 62% (p = 0.008). The mean surgical PCI for all 34 patients was 23.4 compared with MRI 20.0 (p = 0.003) and DCE MRI 24.1 (p = 0.26). The addition of the DCE images improved the accuracy of total PCI by > 10% in 16 (0.46) patients. For PCI regions 9-12, the mean surgical PCI was 6.0 compared with MRI 4.8 (p = 0.08) and DCE 6.6 (p = 0.02). The addition of DCE images improved the accuracy of the regional PCI > 10% in 15 (0.43) patients. CONCLUSIONS: DCE MRI provides a novel contrast tool that improves detection of mesenteric tumor. Depicting small-volume mesenteric tumor is better on DCE MRI compared with conventional MRI.

Cathepsin L-induced galectin-1 may act as a proangiogenic factor in the metastasis of high-grade serous carcinoma.

BACKGROUND: New treatment options for metastasised high-grade serous carcinoma (HGSC) are urgently needed. HGSC frequently metastasises to the omentum, inducing angiogenesis in the local omental microvasculature to facilitate tumour growth. We previously showed that HGSC-secreted cathepsin L (CathL) induces pro-angiogenic changes in disease relevant human omental microvascular endothelial cells (HOMECs), suggesting a role in tumour angiogenesis. Here we investigate whether CathL acts by inducing local production of the carbohydrate-binding protein galectin-1 (Gal1), which has been reported to be involved in tumourigenesis in other tumours. METHODS: HOMECs were used for all experiments. Gal1 mRNA and protein levels were measured by RT-PCR and ELISA respectively. Gal1-induced cell proliferation was assessed using WST-1 assay, migration using a transwell assay and in vivo Gal1 expression by immunohistochemistry. RESULTS: CathL transcriptionally regulated HOMEC production and secretion of Gal1 via activation of NFκB (significantly inhibited by sulfasalazine). Gal1 significantly enhanced HOMEC migration (p < 0.001) and proliferation (p < 0.001), suggesting an autocrine action. The latter was significantly reduced by the MEK/ERK1/2 inhibitors U0126 and PD98059 suggesting downstream activation of this pathway. Immunohistochemical analysis of omenta from HGSC patients with or without metastatic disease demonstrated a positive correlation between Gal1 expression and number of microvessels (r = 0.8702, p < 0.001), and area of vessels (r = 0.7283, p < 0.001), supporting a proangiogenic role for Gal1 in omental metastases. CONCLUSION: HOMEC Gal1 transcription and release in response to CathL secreted from metastasising HGSC acts in an autocrine manner on the local microvasculature to induce pro-angiogenic changes, highlighting a potential new therapeutic target.

The Peculiar Case of a Large Right Lower Quadrant Solitary Fibrous Tumor With Vasculature Arising from the Splenic Artery and Vein.

We present the interesting case of a patient with peritoneal solitary fibrous tumor (SFT). The patient initially presented with right lower quadrant pain. Computed tomography findings revealed the presence of a large mass near the cecum, with both arterial and venous blood supply arising directly from the splenic artery and vein. The patient ultimately underwent surgical excision of the mass, and pathological examination was consistent with benign SFT. Not only is the location of our patient's tumor exceedingly rare, but also, to our knowledge, it is the first reported case of SFT with such a unique vascular supply.

Tumor vascularization is critical for oncolytic vaccinia virus treatment of peritoneal carcinomatosis.

Peritoneal carcinomatosis (PC) represents a significant clinical challenge for which there are few treatment options. Oncolytic viruses are ideal candidates for PC treatment because of their high tumor specificity, excellent safety profile and suitability for peritoneal delivery. Here, we described the use of vvDD-SR-RFP, a recombinant vaccinia virus, in xenograft and syngeneic models of colorectal PC. Colorectal cancer cell lines were highly susceptible to vvDD-SR-RFP replication and cytotoxicity. Intraperitoneal delivery of vvDD-SR-RFP on Day 12 to mice with colorectal carcinomatosis significantly improved survival whereas survival was not improved following virus treatment on Day 8, when tumors were smaller. Immunohistochemistry revealed early tumors had a poorly distributed network of blood vessels and lower proliferation index compared to later tumors. Virus infection was also restricted to tumor rims following Day 8 treatment, whereas it was disseminated in tumors treated on Day 12. Additionally, direct infection of tumor endothelium was observed and virus infection correlated with a loss of endothelial staining and induction of cell death. Our results demonstrate that tumor vasculature has a critical role in virus delivery and tumor response. This will have significant implications in the clinical setting, both in understanding timing of therapies and in designing combination treatment strategies.

Carcinoma-associated fibroblasts derive from mesothelial cells via mesothelial-to-mesenchymal transition in peritoneal metastasis.

Peritoneal dissemination is a frequent metastatic route for cancers of the ovary and gastrointestinal tract. Tumour cells metastasize by attaching to and invading through the mesothelial cell (MC) monolayer that lines the peritoneal cavity. Metastases are influenced by carcinoma-associated fibroblasts (CAFs), a cell population that derives from different sources. Hence, we investigated whether MCs, through mesothelial-mesenchymal transition (MMT), were a source of CAFs during peritoneal carcinomatosis and whether MMT affected the adhesion and invasion of tumour cells. Biopsies from patients with peritoneal dissemination revealed the presence of myofibroblasts expressing mesothelial markers in the proximity of carcinoma implants. Prominent new vessel formation was observed in the peritoneal areas harbouring tumour cells when compared with tumour-free regions. The use of a mouse model of peritoneal dissemination confirmed the myofibroblast conversion of MCs and the increase in angiogenesis at places of tumour implants. Treatment of omentum MCs with conditioned media from carcinoma cell cultures resulted in phenotype changes reminiscent of MMT. Adhesion experiments demonstrated that MMT enhanced the binding of cancer cells to MCs in a ß1-integrin-dependent manner. Scanning electron microscopy imaging showed that the enhanced adhesion was mostly due to increased cell-cell interaction and not to a mere matrix exposure. Invasion assays suggested a reciprocal stimulation of the invasive capacity of tumour cells and MCs. Our results demonstrate that CAFs can derive from mesothelial cells during peritoneal metastasis. We suggest that MMT renders the peritoneum more receptive for tumour cell attachment/invasion and contributes to secondary tumour growth by promoting its vascularization.

Significance of vascular endothelial growth factor in growth and peritoneal dissemination of ovarian cancer.

Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis which drives endothelial cell survival, proliferation, and migration while increasing vascular permeability. Playing an important role in the physiology of normal ovaries, VEGF has also been implicated in the pathogenesis of ovarian cancer. Essentially by promoting tumor angiogenesis and enhancing vascular permeability, VEGF contributes to the development of peritoneal carcinomatosis associated with malignant ascites formation, the characteristic feature of advanced ovarian cancer at diagnosis. In both experimental and clinical studies, VEGF levels have been inversely correlated with survival. Moreover, VEGF inhibition has been shown to inhibit tumor growth and ascites production and to suppress tumor invasion and metastasis. These findings have laid the basis for the clinical evaluation of agents targeting VEGF signaling pathway in patients with ovarian cancer. In this review, we will focus on VEGF involvement in the pathophysiology of ovarian cancer and its contribution to the disease progression and dissemination.

The peritoneal tumour microenvironment of high-grade serous ovarian cancer.

High-grade serous ovarian cancer (HGSC) disseminates early and extensively throughout the peritoneal space, causing multiple lesions that are a major clinical problem. The aim of this study was to investigate the cellular composition of peritoneal tumour deposits in patient biopsies and their evolution in mouse models using immunohistochemistry, intravital microscopy, confocal microscopy, and 3D modelling. Tumour deposits from the omentum of HGSC patients contained a prominent leukocyte infiltrate of CD3(+) T cells and CD68(+) macrophages, with occasional neutrophils. Alpha-smooth muscle actin(+) (α-SMA(+) ) pericytes and/or fibroblasts surrounded these well-vascularized tumour deposits. Using the murine bowel mesentery as an accessible mouse peritoneal tissue that could be easily imaged, and two different transplantable models, we found multiple microscopic tumour deposits after i.p. injection of malignant cells. Attachment to the peritoneal surface was rapid (6-48 h) with an extensive CD45(+) leukocyte infiltrate visible by 48 h. This infiltrate persisted until end point and in the syngeneic murine ID8 model, it primarily consisted of CD3(+) T lymphocytes and CD68(+) macrophages with α-SMA(+) cells also involved from the earliest stages. A majority of tumour deposits developed above existing mesenteric blood vessels, but in avascular spaces new blood vessels tracked towards the tumour deposits by 2-3 weeks in the IGROV-1 xenografts and 6 weeks in the ID8 syngeneic model; a vigorous convoluted blood supply was established by end point. Inhibition of tumour cell cytokine production by stable expression of shRNA to CXCR4 in IGROV-1 cells did not influence the attachment of cells to the mesentery but delayed neovascularization and reduced tumour deposit size. We conclude that the multiple peritoneal tumour deposits found in HGSC patients can be modelled in the mouse. The techniques described here may be useful for assessing treatments that target the disseminated stage of this disease.

Changes in tumor blood flow as measured by Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) may predict activity of single agent bevacizumab in recurrent epithelial ovarian (EOC) and primary peritoneal cancer (PPC) patients: an exploratory analysis of a Gynecologic Oncology Group Phase II study.

OBJECTIVE: To explore feasibility of measuring tumor blood flow as marker for antiangiogenic activity using DCE-MRI (Dynamic Contrast-Enhanced Magnetic Resonance Imaging) in women with recurrent EOC/PPC treated with bevacizumab. METHODS: In a phase II study, 62 patients with recurrent/persistent EOC/PPC were treated with bevacizumab (15 mg/kg IV q21 days) until disease progression. DCE-MRI was performed pre-cycle 1 and 4 of bevacizumab. Images were analyzed retrospectively by a single experienced blinded radiologist. Tumor and muscle contrast enhancement was measured by region of interest signal intensity within the same DCE-MRI images. Flow rates were obtained with concentration of dye as a function of time. Relative blood flow (RBF) was calculated as a ratio of average blood flow into tumor to muscle tissue. Associations between RBF and characteristics/outcomes were explored. RESULTS: Sixty-two patients were eligible for study. Unfortunately, only 14 (23%) patients had imaging data available for analysis at baseline and 13 of those same patients (21%) had imaging data available for analysis pre-cycle 4. The RBF distribution was similar from pre-cycle 1 to 4. RBF remained stable for the majority of the cases (median change -0.21). Baseline RBF was not significantly associated with being progression-free at 6 months, microvessel density, 17 month overall survival, tumor response, or platinum sensitivity. However, increases in blood flow rates were associated with likelihood to be progression-free at 6 months. CONCLUSION: Functional imaging of tumor blood flow is a potential research endpoint that may be explored further. Consideration should be given to timing of endpoint and standardizing the technique.

Emerging therapeutics for primary peritoneal cancer.

INTRODUCTION: Primary peritoneal cancer describes a malignancy that originates from the peritoneal lining of the abdomen. The diagnosis is clearest when the ovaries are uninvolved; however, this is rarely the case and, as such, the declaration is often made pathologically by extrinsic or secondary involvement of the ovaries. The disease shares nearly all of the clinicopathologic features of primary ovarian cancer, most importantly, a molecular homology, which has made it unfruitful for considering it a different entity. Because of this, both standard of care treatment algorithms and contemporary drug development protocols nearly uniformly consider these cancers as primary ovarian cancers. AREAS COVERED: A Medline search was performed as well as a review of trials presented in the National Cancer Institute clinical trials website (http://www.Clinicaltrials.gov). We also reviewed abstracts presented at recent oncology congresses, such as the 2010 Annual meetings of the Society of Gynecologic Oncologists and the American Society of Clinical Oncology. The purpose of this review is to highlight areas of current drug development for patients with primary peritoneal carcinoma. While there are numerous investigational agents being evaluated which follow patients with this disease, our review focuses on the most promising agents that are in mature clinical development. In addition, given the recent positive Phase III data of bevacizumab in the first-line setting for patients with this disease, we consider changes that we can anticipate in this field. EXPERT OPINION: Numerous novel agents are being explored in this disease with the majority focusing on direct and indirect perturbations of tumor angiogenesis. Based on ongoing and recently completed investigations, targeted therapies are likely to become part of the armamentarium of first-line and recurrent treatment for patients with peritoneal cancers. Future studies of pathway-specific targeting will probably include pretreatment biomarker selection or eligibility criteria as well as combinatorial strategies.

Peritoneal metastases: evaluation with contrast-enhanced ultrasound.

OBJECTIVES: The aim of this study is to evaluate the contrast-enhanced ultrasound (CEUS) features of peritoneal metastases. MATERIALS AND METHODS: Unenhanced ultrasound and CEUS were conducted in 25 patients who had confident diagnoses of peritoneal metastases after ultrasound-guided biopsies of peritoneum. B-mode sonograms, color Doppler, CEUS pattern and quantitative analysis of blood perfusion in peritoneal metastases were successively evaluated. RESULTS: Peritoneum became markedly thickened and was well seen as a heterogeneous omental cake at B-mode ultrasound. Color Doppler only detected dotted or strip-like blood flow scattered in the thickened peritoneum and no blood signal was found in any metastatic nodule. At CEUS, the thickened peritoneum enhanced diffusely and parameters of time-intensity curves did not show any significant difference among variant metastases groups. All the metastatic nodules in the peritoneum showed fast radial enhancement and became homogeneous with adjacent parenchyma. These nodules soon became hypoechoic and the contour of the nodule was clearly shown during the wash-out phase. In all the nodules, the time to peak was shorter and peak intensity was higher compared with the peripheral tissue. CONCLUSION: CEUS played a good role in the evaluation of microcirculation and angiogenesis of peritoneal metastases and metastatic nodules in thickened peritoneum.

A pilot trial of intravital microscopy in the study of the tumor vasculature of patients with peritoneal carcinomatosis.

Aberrancies in the tumor microvasculature limit the systemic delivery of anticancer agents, which impedes tumor response. Using human intravital microscopy (HIVM), we hypothesized that HIVM would be feasible in patients with peritoneal carcinomatosis (PC). During cytoreductive surgery with hyperthermic intraperitoneal chemotherapy for PC, HIVM was performed in both tumor and non-tumor areas. The primary outcome was HIVM feasibility to measure vessel characteristics. We secondarily evaluated associations between HIVM vessel characteristics and oncologic outcomes (RECIST response to neoadjuvant therapy and disease-specific survival). Thirty patients with PC were enrolled. Nineteen patients (63.3%) received neoadjuvant therapy. HIVM was feasible in all patients. Compared to non-tumor (control) areas, PC areas had a lower density of functional vessels, higher proportion of non-functional vessels, smaller lumenal diameters, and lower blood flow velocity. Qualitative differences in these vessel characteristics were observed among patients who had partial response, stable disease, or progressive disease after receiving neoadjuvant therapy. However, no statistically significant relationships were found between HIVM vessel characteristics and oncologic outcomes. These novel findings comprise the first-in-human, real-time evidence of the microscopic differences between normal and tumor-associated vessels and form the basis for our larger, ongoing clinical trial appropriately powered to determine the clinical utility of HIVM (NCT03823144).

Anoikis resistant gastric cancer cells promote angiogenesis and peritoneal metastasis through C/EBPß-mediated PDGFB autocrine and paracrine signaling.

Anoikis is a type of programmed cell death induced by loss of anchorage to the extracellular matrix (ECM). Anoikis resistance (AR) is crucial for the survival of metastatic cancer cells in blood, lymphatic circulation and distant organs. Compared to ordinary cancer cells, anoikis resistant cancer cells undergo various cellular and molecular alterations, probably characterizing the cells with unique features not limited to anoikis resistance. However, the molecular mechanisms connecting anoikis resistance to other metastatic properties are still poorly understood. Here, the biological interaction between anoikis resistance and angiogenesis as well as their involvement into peritoneal metastasis of gastric cancer (GC) were investigated in vitro and in vivo. The prognostic value of key components involved in this interaction was evaluated in the GC cohort. Compared to ordinary GC cells, GCAR cells exhibited stronger metastatic and pro-angiogenic traits corresponding to elevated PDGFB secretion. Mechanistically, transcription factor C/EBPß facilitated PDGFB transcription by directly binding to and interacting with PDGFB promoter elements, subsequently increasing PDGFB secretion. Secreted PDGFB promoted the survival of detached GC cells through a C/EBPß-dependent self-feedback loop. Moreover, secreted PDGFB promoted angiogenesis in metastases via activation of the MAPK/ERK signaling pathway in vascular endothelial cells. Both C/EBPß activation level and PDGFB expression were significantly elevated in GC and correlated with metastatic progression and poor prognosis of patients with GC. Overall, interaction between GCAR cells and vascular endothelial cells promotes angiogenesis and peritoneal metastasis of GC based on C/EBPß-mediated PDGFB autocrine and paracrine signaling. C/EBPß-PDGFB-PDGFRß-MAPK axis promises to be potential prognostic biomarkers and therapeutic targets for peritoneal metastasis of GC.

Assessment of Tumor Response in Mice with Ovarian Peritoneal Carcinomatosis using Doppler Ultrasound of the Superior Mesenteric Artery and Celiac Trunk.

The goal of the work described here was to assess the performance of Doppler ultrasound (US) of the superior mesenteric artery (SMA) and celiac trunk (CT) in the evaluation of tumor response in female mice with ovarian peritoneal carcinomatosis treated either with bevacizumab or with carboplatin. Compared with untreated mice, carboplatin-treated mice had a lower weight (23.3 ± 2.0 vs. 27.9 ± 2.9 g, p < 0.001), peritoneal carcinomatosis index (PCI, 11 ± 3 vs. 28 ± 6, p < 0.001), Ki67-positive staining surfaces (p < 0.001), vascular density (p < 0.001), mean blood flow velocity (mBFVel) in the SMA (7.0 ± 1.4 vs. 10.9 ± 1.8 cm/s, p < 0.001) and CT (8.0 ± 1.8 vs. 14.3 ± 4.6 cm/s, p < 0.001) and no ascites. Weight and mBFVel were similar in bevacizumab-treated and untreated mice. The mBFVels in the SMA and CT correlated with the PCI used as an estimation of the tumor burden, R = 0.70 (p < 0.0001) and R = 0.65 (p < 0.0001), respectively. Doppler US allows non-invasive assessment of the effects of anticancer therapy in ovarian peritoneal carcinomatosis-induced mice.

Predictive and prognostic angiogenic markers in a gynecologic oncology group phase II trial of bevacizumab in recurrent and persistent ovarian or peritoneal cancer.

OBJECTIVE: Potential predictive/prognostic angiogenic markers were prospectively examined in a phase II trial of bevacizumab in epithelial ovarian cancer (EOC)/primary peritoneal cancer (PPC). METHODS: Recurrent/persistent EOC/PPC patients were treated with bevacizumab (15 mg/kg IV q21days) until disease progression. Validated-immunohistochemistry (IHC) assays were performed on pre-cycle 1/4 tumor biopsies for CD31-microvessel density (MVD), VEGF-histoscore (HS), p53-HS, and TSP1 image analysis score (IA). Pre-cycle 1/4 serum and plasma VEGF were quantified using a validated-ELISA. RESULTS: CD31-MVD and serum VEGF, evaluated pre-cycle 1 in 41/61 and 51/61 eligible patients, respectively, did not appear to be correlated. High CD31-MVD, categorized at the median, appeared to be associated with tumor response, a 13-month shorter median survival, and an increased risk of death (unadjusted hazard ratio [HR] = 2.2, 95% confidence interval [CI] = 1.067-4.467). In addition, each standard deviation (SD) increase in CD31-MVD appeared to be associated with worse survival in unadjusted and adjusted analyses. IHC and plasma biomarkers did not change with bevacizumab treatment except for serum VEGF, which appeared to decrease during bevacizumab treatment. This decrease was not associated with response. High pre-cycle 1 serum VEGF, categorized at the median, was associated with 22-month shorter median survival and an increased risk of death (unadjusted HR = 2.7, 95% CI = 1.369-5.191). Categorized p53 appeared to be associated with unadjusted survival and each SD increase in TSP1-IA appeared to be associated with a decreased risk of progression in unadjusted and adjusted analyses. CONCLUSIONS: Despite the limitations in sample size and exploratory nature of the study, angiogenic markers in tumor and serum may provide prognostic value in recurrent/persistent EOC/PPC, and are being prospectively evaluated in the GOG phase III trial of carboplatin, paclitaxel and bevacizumab/placebo in previously untreated EOC/PPC.

Poor perfusion of the microvasculature in peritoneal metastases of ovarian cancer.

Most women with epithelial ovarian cancer (EOC) suffer from peritoneal carcinomatosis upon first clinical presentation. Extensive peritoneal carcinomatosis has a poor prognosis and its pathophysiology is not well understood. Although treatment with systemic intravenous chemotherapy is often initially successful, peritoneal recurrences occur regularly. We hypothesized that insufficient or poorly-perfused microvasculature may impair the therapeutic efficacy of systemic intravenous chemotherapy but may also limit expansive and invasive growth characteristic of peritoneal EOC metastases. In 23 patients with advanced EOC or suspicion thereof, we determined the angioarchitecture and perfusion of the microvasculature in peritoneum and in peritoneal metastases using incident dark field (IDF) imaging. Additionally, we performed immunohistochemical analysis and 3-dimensional (3D) whole tumor imaging using light sheet fluorescence microscopy of IDF-imaged tissue sites. In all metastases, microvasculature was present but the angioarchitecture was chaotic and the vessel density and perfusion of vessels was significantly lower than in unaffected peritoneum. Immunohistochemical analysis showed expression of vascular endothelial growth factor and hypoxia inducible factor 1α, and 3D imaging demonstrated vascular continuity between metastases and the vascular network of the peritoneum beneath the elastic lamina of the peritoneum. We conclude that perfusion of the microvasculature within metastases is limited, which may cause hypoxia, affect the behavior of EOC metastases on the peritoneum and limit the response of EOC metastases to systemic treatment.

Use of an anti-vascular endothelial growth factor antibody in a pharmacokinetic strategy to increase the efficacy of intraperitoneal chemotherapy.

The efficacy of intraperitoneal chemotherapy for ovarian cancers is limited by poor penetration of drug into peritoneal tumors. Based on pharmacokinetic theory that suggests that penetration depth is primarily determined by the rate of drug removal via tumor capillaries, we have hypothesized that co-administration of antiangiogenic therapy will allow for decreased drug removal, increased drug concentrations in tumor, and increased efficacy of intraperitoneal chemotherapy. Pharmacokinetic modeling was conducted to simulate the effect of tumor blood flow on tumor concentrations of topotecan. Simulations predicted that tumor blood flow reductions, as potentially achieved by antiangiogenic therapy, would lead to substantial increases in tumor concentrations after intraperitoneal chemotherapy but would lead to a slight decrease after systemic chemotherapy. Pharmacokinetic studies performed using the A2780 xenograft tumor model showed that animals receiving combined intraperitoneal topotecan and an anti-vascular endothelial growth factor (VEGF) monoclonal antibody had approximately 6.5-fold higher (p = 0.0015) tumor topotecan concentrations compared with animals receiving intraperitoneal topotecan alone, whereas there was no significant (p = 0.16) difference for systemic topotecan. Therapeutic studies conducted with two different drugs, topotecan and cisplatin, showed that animals receiving combined intraperitoneal chemotherapy and anti-VEGF therapy displayed superior survival relative to animals treated with chemotherapy alone (i.e., cisplatin or topotecan), anti-VEGF alone, or intravenous chemotherapy with concomitant anti-VEGF therapy. Combined intraperitoneal topotecan and anti-VEGF resulted in the complete cure of four of 11 mice. The proposed combination of antiangiogenic therapy and intraperitoneal chemotherapy, which was predicted to be beneficial by pharmacokinetic simulations, may provide substantial benefit to patients with peritoneal malignancies.

Interobserver variation in the reporting of local peritoneal involvement and extramural venous invasion in colonic cancer.

AIMS: Local peritoneal involvement (LPI) and extramural venous invasion (EMVI) are of prognostic value in Dukes' B colonic cancers and may be used to select patients for adjuvant chemotherapy. There is marked variation in the frequency with which they are reported however, ranging from 7% to 39% and 10% to 90%, respectively. A grading system for diagnosing LPI has been proposed by Shepherd et al. and partially incorporated into the Royal College of Pathologists guidelines for reporting colorectal cancer. This study aimed to determine the degree of interobserver variation in the reporting of LPI and EMVI amongst a group of experienced pathologists with a special interest in gastrointestinal pathology. METHODS AND RESULTS: Four pathologists specialising in gastrointestinal pathology independently assessed LPI according to the grading system described by Shepherd et al. and the presence or absence of EMVI on 138 and 131 slides of pT3 and pT4 colonic cancers, respectively. Kappa statistics were performed to assess interobserver agreement. Kappa values for LPI ranged from kappa = 0.74 (substantial agreement) to kappa = 0.89 (almost perfect agreement). Kappa values for EMVI ranged from kappa = 0.29 (poor agreement) to kappa = 0.59 (moderate agreement). CONCLUSIONS: Using Shepherd's grading system there was good agreement between pathologists in reporting LPI in colonic carcinomas. The reporting of EMVI in colonic carcinomas on haematoxylin and eosin-stained slides had only poor to moderate agreement however, even amongst gastrointestinal pathologists working together in a single unit. Introduction of standardized criteria and/or the use of an elastin stain in the diagnosis of EMVI may assist in improving interobserver agreement.

Effect of bevacizumab, a humanized monoclonal antibody to vascular endothelial growth factor, on peritoneal metastasis of MNK-45P human gastric cancer in mice.

BACKGROUND: The aim of this study was to clarify the effect of bevacizumab on gastric cancer with peritoneal metastasis in nude mice. MATERIALS AND METHODS: The expression of vascular endothelial growth factor mRNA (VEGF mRNA) in four gastric cancer cell lines, NCI-N87, MKN-45, MKN-45P, and Kato-III, was examined by polymerase chain reaction. We created a model of peritoneal metastasis by injecting mice with the human gastric cancer cell line MKN-45P. Mice were injected intraperitoneally with bevacizumab (0.1 mg/100 microL) on days 5-14, after inoculation (n = 10) or with phosphate-buffered saline (PBS) over the same time period (n = 10). The maximum abdominal circumference, ascites volume, and the total number and weight of peritoneal tumors were measured. To assess the effect of bevacizumab on angiogenesis, immunohistochemical analysis was performed. RESULTS: VEGF mRNA was expressed at a high level in MKN-45P cells as well as MKN-45 and Kato-III. The mean maximum abdominal circumference and ascites volume in the bevacizumab group were significantly less than those in the control group (P < 0.001, respectively). The total weight of disseminated tumors in the bevacizumab group was also significantly less than that in the control group (P < 0.01). In addition, immunohistochemical analysis of CD31-stained peritoneally disseminated nodules showed that the vessel area in the bevacizumab group was significantly less than that in the control group (P < 0.001). CONCLUSIONS: These results show that intraperitoneal administration of bevacizumab inhibits peritoneal metastasis and reduces malignant ascites in tumor-bearing mice.

Digital subtraction angiography of the superior mesenteric artery: identifying arterial branches.

This "problem in diagnostic imaging" provides an overview of the technique of digital subtraction angiography. The possibility of artefacts arising from movement subsequent to the taking of the masking image is discussed. It is also important that contrast medium is allowed to backflow into the parent vessel (in this case the aorta) to ensure that there has been filling of the proximal branches of the vessel of interest (in this case the superior mesenteric artery). An accessory middle colic artery is demonstrated. Detection of such variant vessels is important not only to surgeons but also to specialist radiologists carrying out therapeutic embolization.