Current Nonoperative Therapeutic Interventions for Lower Gastrointestinal Hemorrhage.

Lower gastrointestinal hemorrhage remains a common cause of hospitalization, with significant health care costs. Initial management should include aggressive resuscitation followed by localization of bleeding with nuclear scintigraphy, colonoscopy, or computed tomography (CT) angiography. If bleeding does not resolve spontaneously, expeditious intervention with minimally invasive endoscopic or angiographic methods is necessary with surgical intervention as a last resort.

Percutaneous endoscopic sigmoidopexy using T-fasteners for management of sigmoid volvulus.

BACKGROUND: Sigmoid volvulus (SV) is the third leading cause of large bowel obstruction after colonic neoplasms and diverticular disease. SV has traditionally been managed via endoscopic detorsion and decompression followed by non-emergent surgical resection owing to the high risk of recurrence. Most cases of SV occur in elderly debilitated patients with multiple comorbidities and may not be candidates for surgical resection. Endoscopic sigmoidopexy has been described as an alternative to surgical resection. Here, we describe our experience with endoscopic sigmoidopexy using T-fasteners. METHODS: Three patients with recurrent SV that were identified as poor surgical candidates by our colorectal surgery team underwent endoscopic sigmoidopexy. The patients received preoperative bowel preparation. A colonoscope was inserted and the site of the volvulus was visualized and assessed for adequate decompression. Subsequently, four points of fixation were identified and T-fasteners were deployed. RESULTS: Two patients underwent successful sigmoidopexy without any complications or recurrence on follow-up. One patient developed post procedure pneumoperitoneum that was successfully treated conservatively; however, he passed away from their underlying comorbidities. CONCLUSION: Overall, preliminary results for sigmoidopexy using T-fasteners have been promising, offering a potential option to prevent recurrence in high risk patients unsuitable for surgical intervention.

Surgical residents and the adequacy of dictated operative reports.

INTRODUCTION: The surgeon's clinical note has been previously shown to poorly reflect both physician-centered and patient-centered outcomes. We hypothesized that dictated operative reports do not adequately demonstrate surgeons' workload, preoperative involvement, clinical decision-making, or core competencies. MATERIALS AND METHODS: We retrospectively reviewed operative reports in the month of January for the years 2007-2011. Operative reports were dictated by interns, residents (R1-R5), and surgical staff. All resident reports were approved by staff surgeons. We qualitatively assessed each for 15 items that encompassed physician-centered outcomes, patient-centered outcomes, and Joint Commission/Medicare-required fields. Groups were compared to each other with 1-way analysis of variance with Bonferroni correction. RESULTS: We reviewed 999 operative reports. Nearly every chart included an indication and preoperative and postoperative diagnoses. Only 57.3% listed whether or not there were any complications. Half recorded operative findings. The mean number of fields missed based on level of surgical training was R1: 4.83, R2: 4.46, R3: 3.68, R4: 3.35, R5: 3.29, and staff: 3.09. Interns and second-year residents missed significantly more data fields than upper-level residents and staff (P < 0.0001). Staff surgeons missed fewer data fields than third-year residents (P = 0.004). There was no statistical difference between R4, R5, and surgical staff (P > 0.999). CONCLUSIONS: The dictated operative report does not accurately document preoperative surgeon involvement, clinical decision-making, maintenance of core competencies, or full compliance with Joint Commission regulations. Focused education and enhanced staff oversight of junior-level dictated operative reports might be required to improve quality.

Malignant triton tumor below the peritoneal reflection: a case report.

Malignant triton tumor (MTT) is a rare subtype of malignant peripheral nerve sheath tumors (MPNSTs) histologically defined by rhabdomyoblastic differentiation. MTTs are primarily found in the head, neck, extremities and trunk, but rare cases of MTT within the buttock, the mediastinum and the retroperitoneum have also been documented. We present the case of a 47-year-old male patient who initially presented with right flank pain and hematuria in July 2019, who was found to have a large pelvic mass below peritoneal reflection. Complete resection of the mass was performed, and pathology identified the mass as a MTT.

Inhibition of cyclooxygenase-2 disrupts tumor vascular mural cell recruitment and survival signaling.

Much evidence supports an important role for the inducible enzyme cyclooxygenase-2 (COX-2) in tumor angiogenesis. Previous studies have focused on the role of COX-2 in stimulating endothelial proliferation, with blockade of this enzyme impairing endothelial homeostasis. However, recent data suggest that COX-2 also regulates molecules implicated in endothelial trafficking with pericytes/vascular mural cells (VMC), an interaction crucial to vessel stability. We investigated the role of COX-2 in vascular assembly by testing the effect of the specific COX-2 inhibitor SC-236 in an orthotopic xenograft model of human Wilms' tumor. Tumor growth was significantly suppressed by SC-236 (78% at day 28, 55% at day 35). Perfusion studies and immunostaining showed a marked decrease in vasculature, particularly in small vessels. Specifically, SC-236 inhibited participation of VMC in xenograft vessels. SC-236-treated tumors developed segmentally dilated, architecturally erratic tumor vessels with decreased nascent pericytes and scant mature VMC. Although vascular endothelial growth factor expression was unchanged, expression of the chemokine receptor CXCR4 was decreased in tumor vessels, consistent with defective homing of vascular progenitor cells. Vascular expression of phosphorylated platelet-derived growth factor receptor-beta was also diminished, indicating impaired VMC-endothelial trafficking. Consistent with the key role of this interaction in vessel homeostasis, vascular cells in SC-236-treated tumors displayed markedly diminished phosphorylated Akt, indicating disrupted survival signaling. These results show that SC-236 causes defective vascular assembly by attenuating incorporation of VMC into tumor vessels, impairing endothelial survival, and raise the possibility that blockade of COX-2 may provide therapeutic synergies with antiangiogenic molecules that more selectively target endothelial cells.

TNP-470 promotes initial vascular sprouting in xenograft tumors.

TNP-470 (AGM-1470), an analogue of fumagillin, was one of the first molecules proposed to have antiangiogenic properties. This concept was based on its ability to inhibit both endothelial proliferation in vitro and tumor growth in vivo in a number of xenograft models. Yet, subsequent investigations indicated that the biochemical activities associated with TNP-470 are not selective for endothelial cells. Moreover, recent evidence suggests that this agent inhibits tumor growth in vivo, but without a corresponding decrease in angiogenesis. Therefore, we performed a detailed comparison of TNP-470 to a validated antiangiogenic agent, a VEGF inhibitor termed VEGF-Trap, using a xenograft model of Wilms tumor. Treatment with TNP-470 for 5 weeks significantly suppressed xenograft growth (83%). Surprisingly, this inhibition was not associated with a decrease in angiogenesis, but instead with an increase in tiny neovessels. To determine whether this was a direct effect of TNP-470 on tumor vessels, we examined its effect in a short-term assay using large tumors with established vasculature. In contrast to treatment with VEGF-Trap, which led to rapid vessel regression and tumor hypoxia, tumors exposed to TNP-470 for 1 day displayed increased capillary sprouting, with significantly increased microvessel density, vessel length, and branch points. TNP-470 did not induce tumor hypoxia as demonstrated by minimal pimonidazole staining and VEGF expression. TNP-470 did, however, cause a marked increase in apoptosis of tumor cells. Our results indicate that the antitumor effects of TNP-470 cannot be attributed to prevention of neoangiogenesis, but instead to its direct action on tumor cells.

Early Diagnosis of a Small Adenocarcinoma in a Rectovaginal Fistula Related to Crohn's Disease.

While adenocarcinomas have occasionally been reported in perianal fistulae, malignant changes occurring in rectovaginal fistulae are rare, with only a handful of reported cases. We report a 73-year-old woman with Crohn's disease who was diagnosed at an early stage with adenocarcinoma in a rectovaginal fistula. This rare disease poses many diagnostic challenges.

Effects of potent VEGF blockade on experimental Wilms tumor and its persisting vasculature.

We characterized the effect of potent vascular endothelial growth factor (VEGF) blockade on early-stage Wilms tumor xenograft growth, vasculature and metastasis. VEGF is a key mediator of both physiologic and tumor angiogenesis. We recently described that potent VEGF blockade induces regression of established Wilms tumor xenografts and vessels, also reducing the size but not the incidence of pre-existing metastases. In these studies, we examined the effects of potent VEGF blockade on earlier stages of experimental Wilms tumors, focusing on tumor growth, vasculature and metastasis. Athymic mice received intrarenal human Wilms tumor cell implants. Biweekly treatment with vehicle or the VEGF-Trap, a high-affinity soluble decoy receptor incorporating regions of VEGFR1 and VEGFR2, was begun 1 week later (100 or 500 micrograms/dose, n=20 in each group). Mice were euthanized at week 6 to examine tumor weight, incidence of lung metastases, vascularity and expression of angiogenic factors. A cohort of mice was examined 2 weeks after cessation of treatment. Compared to controls, VEGF-Trap treated tumors were significantly smaller (100 micrograms/dose: 92.7% smaller, p=0.0017; 500 micro g/dose: 99.0% smaller, p=0.0009). The incidence of lung metastasis also decreased significantly (p<0.0055). VEGF-Trap nearly eradicated tumor vasculature. Rare persisting vessels were characterized by large caliber, quiescence (lacking proliferation/apoptosis) and arterialization (both phenotypic and molecular). Potent VEGF blockade caused near-arrest of experimental Wilms tumor growth, resulted in nearly avascular tumors, and also decreased the incidence and size of metastases. Persistent vessels in tumors treated with VEGF-Trap displayed specific morphologic and molecular features, suggestive of arterialization. Future strategies that target these persisting vessels may enhance the efficacy of VEGF blockade therapy.

Thalidomide is anti-angiogenic in a xenograft model of neuroblastoma.

Thalidomide has previously been shown to have anti-angiogenic properties. More recently, clinical efficacy of this agent has been demonstrated in multiple myeloma and prostate cancer. Neuroblastoma is the most frequent solid tumor of the abdomen of childhood, yet children with this disease frequently have metastases at presentation. Such patients have a very poor prognosis with current therapies. Thus, new approaches are needed. We have previously shown that VEGF antagonists can inhibit neoangiogenesis and tumor growth in experimental neuroblastoma. In this study, we investigated the anti-angiogenic and anti-tumor properties of thalidomide in a xenograft model of human neuroblastoma. Tumors were induced in athymic mice using the human neuroblastoma cell line NGP. Intraperitoneal thalidomide (100 mg/kg/dose) or vehicle was administered beginning one week after implantation, and animals euthanized at six weeks. Thalidomide treatment did not significantly alter tumor growth as compared with controls. However, thalidomide suppressed angiogenesis, as demonstrated both by fluorescein angiography and immunohistochemical staining, and induced apoptosis of endothelial cells in neuroblastoma xenografts. Quantification of microvessel density demonstrated a significant reduction of vasculature in treated tumors (p<0.004). Thalidomide induced co-option of host vasculature, an effect noted previously after VEGF blockade. This study demonstrates that thalidomide has anti-angiogenic properties in experimental neuroblastoma.

Blockade of her2/neu decreases VEGF expression but does not alter HIF-1 distribution in experimental Wilms tumor.

Her2/neu regulates angiogenesis in human breast cancer, in part by stabilizing hypoxia-inducible factor 1alpha (HIF-1alpha), causing accumulation of the HIF-1 heterodimer and thus increasing expression of the proangiogenic cytokine VEGF. Her2/neu has recently been shown to be overexpressed in a subset of Wilms tumors. Using her2/neu (+) and her2/neu (-) Wilms tumor cell lines, we tested the effect of blocking anti-her2/neu antibody in vitro and in vivo. Blocking antibody did not alter VEGF expression in vitro, but decreased expression of VEGF in her2/neu (+) Wilms tumor xenografts. Tumor suppression was less marked than in parallel experiments using agents directly blocking VEGF. HIF-1alpha immunostaining was not altered in her2/neu (+) xenografts exposed to blocking antibody. These results suggest that her2/neu contributes to Wilms tumor angiogenesis in vivo by regulating VEGF, but other processes may act to rescue HIF-1alpha and thus to support tumor growth in this system.

Biomolecular markers and involution of hemangiomas.

BACKGROUND/PURPOSE: Vascular anomalies are a diverse set of lesions with distinct clinical behaviors, whose biomolecular characteristics are largely undefined. Common hemangiomas proliferate during the first year of life, then involute at a variable pace over several years. Other vascular tumors may involute much more quickly (rapidly involuting congenital hemangiomas [RICH]), not at all (lymphatic malformation), or display malignant behavior (angiosarcoma). Key cytokines driving angiogenesis include vascular endothelial growth factor (VEGF) family members/receptors (placental growth factor [PIGF], VEGF-A, and VEGF-C) and angiopoietins. The authors hypothesized that involuting hemangiomas would display biologic markers distinctly different from noninvoluting vascular lesions. METHODS: Six patient samples were analyzed: (1) RICH, (2) proliferating hemangioma, (3) involuting hemangioma, (4) tufted angioma, (5) hepatic angiosarcoma, and (6) lymphatic malformation. Detailed examination of endothelial/vascular mural cell status was performed by fluorescent double-label immunostaining using specific markers (PECAM-1, alphaSMA) in combination with markers of proliferation (anti-phospho-histone H3) or apoptosis (TUNEL). Expression of PIGF, VEGF-A, VEGF-C, and Ang-1 was localized by in situ hybridization. RESULTS: Involuting/proliferating common hemangiomas demonstrated vasculature with abundant vascular mural cells (alphaSMA+); in contrast, alphaSMA(+) cells were rare in RICH vessels. Endothelial apoptosis was increased dramatically, but proliferation was unchanged during involution. VEGF-A was expressed in all lesions except lymphatic malformation, which displayed VEGF-C and Ang-1 upregulation. Strikingly, PIGF expression was increased markedly in the lesions predicted to involute/actively involuting but was virtually absent from noninvoluting tumors. CONCLUSIONS: Vessel architecture and endothelial/vascular mural cell status differed between lesions, differentiating even common versus rapidly involuting hemangioma and corresponded to clinical involution. VEGF-A expression characterized endothelial-derived lesions, whereas VEGF-C marked lymphatic-derived cells. PIGF expression occurred only in vascular anomalies predicted to involute or actively involuting, a pattern potentially linked to PIGF function as a conditional antagonist of VEGF-A. Thus, distinct patterns of morphology and angiogenic factor expression characterize vascular anomalies with different clinical behaviors.

Regression of established tumors and metastases by potent vascular endothelial growth factor blockade.

Vascular endothelial growth factor (VEGF) is a critical promoter of blood vessel growth during embryonic development and tumorigenesis. To date, studies of VEGF antagonists have primarily focused on halting progression in models of minimal residual cancer. Consistent with this focus, recent clinical trials suggest that blockade of VEGF may impede cancer progression, presumably by preventing neoangiogenesis. However, VEGF is also a key mediator of endothelial-vascular mural cell interactions, a role that may contribute to the integrity of mature vessels in advanced tumors. Here, we report that high-affinity blockade of VEGF, using the recently described VEGF-Trap, abolishes mature, preexisting vasculature in established xenografts. Eradication of vasculature is followed by marked tumor regression, including regression of lung micrometastases. Thus, the contribution of relatively low levels of VEGF to vessel integrity may be critical to maintenance of even very small tumor masses. Potent blockade of VEGF may provide a new therapeutic option for patients with bulky, metastatic cancers.

Human epidermal growth factor receptor signaling contributes to tumor growth via angiogenesis in her2/neu-expressing experimental Wilms' tumor.

BACKGROUND: The human epidermal growth factor family (HER) members play a significant role in the mesenchymal-to-epithelial transition during renal tubulogenesis. HER misexpression has been linked also to loss of growth control, invasiveness, and promotion of angiogenesis in breast cancers and other human malignant tumors METHODS: The authors screened Wilms' tumor samples and derived cell lines for expression of her2/neu, which was detected in both unfavorable and favorable histology tissues. Xenografts were implanted in mice using her2/neu(+) and her2/neu(-) cell lines and the effect of specific blockade tested using monoclonal anti-her2/neu antibody. RESULTS: Blocking antibody suppressed tumor growth in her2/neu(+) but not her2/neu(-) experimental Wilms' tumor. In addition, antibody exposure resulted in suppression of tumor angiogenesis but no decrease in tumor cell proliferation in her2/neu(+) xenografts. CONCLUSIONS: Her2/neu contributes to the growth of some Wilms' tumors, and an important mechanism of its action is promotion of angiogenesis.

Potent VEGF blockade causes regression of coopted vessels in a model of neuroblastoma.

Vascular endothelial growth factor (VEGF) plays a key role in human tumor angiogenesis. We compared the effects of inhibitors of VEGF with different specificities in a xenograft model of neuroblastoma. Cultured human neuroblastoma NGP-GFP cells were implanted intrarenally in nude mice. Three anti-VEGF agents were tested: an anti-human VEGF(165) RNA-based fluoropyrimidine aptamer; a monoclonal anti-human VEGF antibody; and VEGF-Trap, a composite decoy receptor based on VEGFR-1 and VEGFR-2 fused to an Fc segment of IgG1. A wide range of efficacy was observed, with high-dose VEGF-Trap causing the greatest inhibition of tumor growth (81% compared with controls). We examined tumor angiogenesis and found that early in tumor formation, cooption of host vasculature occurs. We postulate that this coopted vasculature serves as a source of blood supply during the initial phase of tumor growth. Subsequently, control tumors undergo vigorous growth and remodeling of vascular networks, which results in disappearance of the coopted vessels. However, if VEGF function is blocked, cooption of host vessels may persist. Persistent cooption, therefore, may represent a novel mechanism by which neuroblastoma can partly evade antiangiogenic therapy and may explain why experimental neuroblastoma is less susceptible to VEGF blockade than a parallel model of Wilms tumor. However, more effective VEGF blockade, as achieved by high doses of VEGF-Trap, can lead to regression of coopted vascular structures. These results demonstrate that cooption of host vasculature is an early event in tumor formation, and that persistence of this effect is related to the degree of blockade of VEGF activity.