C. Collins

A prospective study of common bile duct calculi in patients undergoing laparoscopic cholecystectomy: Natural history of choledocholithiasis revisited

Objective:To define the incidence of problematic common bile duct calculi in patients undergoing laparoscopic cholecystectomy. Summary Background Data:In patients selected for laparoscopic cholecystectomy, the true incidence of potentially problematic common bile duct calculi and their natural history has not been determined. We evaluated the incidence and early natural history of common bile duct calculi in all patients undergoing laparoscopic cholecystectomy with intraoperative and delayed postoperative cholangiography. Methods:Operative cholangiography was attempted in all patients. In those patients in whom a filling defect was noted in the bile duct, the fine bore cholangiogram catheter was left securely clipped in the cystic duct for repeated cholangiography at 48 hours and at approximately 6 weeks postoperatively. Results:Operative cholangiography was attempted in 997 consecutive patients and was accomplished in 962 patients (96%). Forty-six patients (4.6%) had at least one filling defect. Twelve of these had a normal cholangiogram at 48 hours (26% possible false-positive operative cholangiogram) and a further 12 at 6 weeks (26% spontaneous passage of calculi). Spontaneous passage was not determined by either the number or size of calculi or by the diameter of the bile duct. Only 22 patients (2.2% of total population) had persistent common bile duct calculi at 6 weeks after laparoscopic cholecystectomy and retrieved by endoscopic retrograde cholangiopancreatography. Conclusions:Choledocholithiasis occurs in 3.4% of patients undergoing laparoscopic cholecystectomy but more than one third of these pass the calculi spontaneously within 6 weeks of operation and may be spared endoscopic retrograde cholangiopancreatography. Treatment decisions based on assessment by operative cholangiography alone would result in unnecessary interventions in 50% of patients who had either false positive studies or subsequently passed the calculi. These data support a short-term expectant approach in the management of clinically silent choledocholithiasis in patients selected for LC.

Electrochemotherapy: Aspects of Preclinical Development and Early Clinical Experience

Objective:To develop an optimized, reproducible system of electrochemotherapy, and to investigate its clinical application in patients with cutaneous or subcutaneous recurrences of inoperable or progressive disease recalcitrant to current anticancer treatments. Background:Electrochemotherapy is the application of electric pulses to tumor tissue, rendering the cell membranes permeable to otherwise impermeant or poorly permeant anticancer drugs. This facilitates a potent local cytotoxic effect. Study Design:The optimal parameters for electrical pulses and bleomycin concentration were obtained in vitro and then applied to tumors derived from 4 histologically distinct human cancer cell lines (7860, PC3, OE19, MCF-7) established in athymic nude mice. Comparison was made with tumors that received bleomycin alone, electric pulses alone, and untreated controls. The optimized electrochemotherapy was then applied to patients with cutaneous or subcutaneous tumors, of any histologic type, recurrent or metastatic and unresponsive to standard chemotherapy and/or radiotherapy regimens. Tumors were assessed at monthly intervals to determine response to the treatment. Results:In vivo: Using the optimal parameters ascertained in vitro, all tumors treated by electrochemotherapy with bleomycin (n = 24) had significantly regressed (P < 0.001, all 4 lines) compared with control tumors (n = 72). Twelve tumors completely regressed (50%) following a single application, with 12 partial regressions (50%). Clinical: In 30 patients (111 tumors), none of the treated tumors progressed. Sixty percent of tumors (66 of 111) showed complete regression, 22% (24 of 111) partial response, and 18% (21 of 111) no change. Electrochemotherapy was more effective in smaller tumors (<3 cm), 71% (64 of 90) showing complete regression, 20% (18 of 90) partial response, and 9% (8 of 90) no change. Conclusions:Electrochemotherapy parameters optimized in vitro are applicable in vivo. This treatment is effective in athymic nude mice for all histologic types indicating a nonimmunologic mode of action. In clinical application, electrochemotherapy is an effective, safe, and reproducible therapy. Patients with cutaneous or subcutaneous tumors previously refractory to surgical intervention, systemic chemotherapy, and/or radiotherapy responded successfully irrespective of histologic type.

Local gene therapy of solid tumors with GM-CSF and B7-1 eradicates both treated and distal tumors.

Gene therapy-induced expression of immunostimulatory molecules at tumor cell level may evoke antitumor immune mechanisms by recruiting and enhancing viability of antigen-processing cells and specific tumoricidal lymphocytes. The antitumor efficacy of a plasmid, coding for granulocyte–macrophage colony-stimulating factor (GM-CSF) and the B7-1 costimulatory immune molecule, delivered into growing solid tumors by electroporation was investigated. Murine fibrosarcomas (JBS) growing in Balb/C mice (⩽100 mm3) were transfected with GM-CSF/B7-1-expressing plasmid. Complete tumor regression occurred in greater than 60% of treated animals. This response was systemic, durable and tumor specific, with all responding animals resistant to repeat tumor challenge. Using a liver metastatic model, effective cure of distal metastases was achieved following treatment of the primary subcutaneous tumor. This treatment strategy could be applicable in the clinical setting for effective elimination of both primary tumors and associated metastatic disease.

Probiotics: An Emerging Therapy

There is considerable clinical interest in the utility of probiotic therapy--the feeding of (live) non-pathogenic bacteria, originally derived from the alimentary tract, for disease treatment or health promotion. The microflora of the gastrointestinal tract is essential for mucosal protection, for immune education and for metabolism of fecal residue. Physiological disturbances of these processes, when they occur, result from: i) alteration of a microbial ecosystem, originally conserved by evolution; ii) reduced consumption of microorganisms; iii) invasion of pathogens; or iv) modern interventions. Recent data support the use of proven probiotic organisms in prevention and treatment of flora-related gastrointestinal disorders including inflammatory bowel disease, infectious and antibiotic related diarrheas, and post-resection disorders including pouchitis. Therapeutic activity of probiotic bacteria can be due to competition with pathogens for nutrients and mucosal adherence, production of antimicrobial substances, and modulation of mucosal immune functions. Although a promising treatment, controlled clinical trials are necessary to validate the benefit of probiotics.

Non-viral in vivo immune gene therapy of cancer: combined strategies for treatment of systemic disease

Many patients with various types of cancers have already by the time of presentation, micrometastases in their tissues and are left after treatment in a minimal residual disease state [Am J Gastroenterol 95(12), 2000]. To prevent tumour recurrence these patients require a systemic based therapy, but current modalities are limited by toxicity or lack of efficacy. We have previously reported that immune reactivity to the primary tumour is an important regulator of micrometastases and determinant of prognosis. This suggests that recruitment of specific anti-tumour mechanisms within the primary tumour could be used advantageously for tumour control as either primary or neo-adjuvant treatments. Recently, we have focused on methods of stimulating immune eradication of solid tumours and minimal residual disease using gene therapy approaches. Gene therapy is now a realistic prospect and a number of delivery approaches have been explored, including the use of viral and non-viral vectors. Non-viral vectors have received significant attention since, in spite of their relative delivery inefficiency, they may be safer and have greater potential for delivery of larger genetic units. By in vivo electroporation of the primary tumour with plasmid expressing GM-CSF and B7-1, we aim to stimulate immune eradication of the treated tumour and associated metastases. In this symposium report, we describe an effective gene based approach for cancer immunotherapy by inducing cytokine and immune co-stimulatory molecule expression by the growing cells of the primary tumour using a plasmid electroporation gene delivery strategy. We discuss the potential for enhancement of this therapy by its application as a neoadjuvant to surgical excision and by its use in combination with suppressor T cell depletion.

Immune gene therapy as a neoadjuvant to surgical excision to control metastatic cancers

We investigated if the range of efficacy of a gene-based immunotherapy of solid tumours against systemic disease could be extended when used as a neoadjuvant to surgery. Hundred percent mice whose subcutaneous tumours were surgically removed 4 days post-electroporation with GM-CSF and B7-1 plasmid were systemically resistance to tumour rechallenge. In mice bearing both subcutaneous and hepatic tumours, neoadjuvant treatment of the primary tumour resulted in significant reduction in, or elimination of, hepatic tumour growth, with a significant increase in survival, indicating that control of the primary tumour by immunotherapy was not a prerequisite for containment of systemic disease.

VHL genetic alteration in CCRCC does not determine de-regulation of HIF, CAIX, hnRNP A2/B1 and osteopontin

Background: von Hippel–Lindau (VHL) tumour suppressor gene inactivation is associated with clear cell renal cell carcinoma (CCRCC) development. The VHL protein (pVHL) has been proposed to regulate the expression of several proteins including Hypoxia Inducible Factor-α (HIF-α), carbonic anhydrase (CA)IX, heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 and osteopontin. pVHL has been characterized in vitro, however, clinical studies are limited. We evaluated the impact of VHL genetic alterations on the expression of several pVHL protein targets in paired normal and tumor tissue. Methods: The VHL gene was sequenced in 23 CCRCC patients and VHL transcript levels were evaluated by real-time RT-PCR. Expression of pVHL’s protein targets were determined by Western blotting in 17 paired patient samples. Results: VHL genetic alterations were identified in 43.5% (10/23) of CCRCCs. HIF-1α, HIF-2α and CAIX were up-regulated in 88.2% (15/17), 100% (17/17) and 88.2% (15/17) of tumors respectively and their expression is independent of VHL status. hnRNP A2/B1 and osteopontin expression was variable in CCRCCs and had no association with VHL genetic status. Conclusion: As expression of these proposed pVHL targets can be achieved independently of VHL mutation (and possibly by hypoxia alone), these data suggests that other pVHL targets may be more crucial in renal carcinogenesis.

Thoracoscopic repair of instrumental perforation of the oesophagus: first report

BackgroundPerforation of the oesophagus is a life-threatening condition requiring early recognition and repair to prevent mediastinitis and death. Primary closure with mediastinal drainage is recognised as the treatment of choice for patients presenting within 24 hours. Many are frail, however, and unsuitable for major surgery. Aim To report the first case of thoracoscopic repair of the oesophagus for oesophageal perforation following instrumentation.MethodsFlexible endoscopy revealed a 10cm perforation in the right lower oesophagus. With the gastroscope in the oesophagus, four thoracoports were introduced. Using suction and irrigation, the pleural cavity was suctioned free of debris and a 10cm longitudinal tear of the right lateral aspect of the oesophagus was repaired using interrupted polyglactin sutures through all layers.ResultsThe patient tolerated the procedure well and made an uncomplicated recovery. Conclusion The uncomplicated recovery of this frail patient without need for blood transfusions or assisted ventilation supports the notion that the thoracoscopic approach may have significant advantages. With increased experience and technical refinements there should be less reluctance to refer these patients for earlier definitive surgical repair.

Immunogenetherapy of solid tumours using electroporation to deliver GMCSF/B7-1 combination piasmid

ConclusionImmunogene-therapy of solid tumours, by electroporation with GMCSF/B7-1 plasmid induces effective local and systemic durable anti-tumoral immune responses; applicable to primary tumours and associated minimal residual disease.

Abstract 2847: PECAM-1 targeting extends overall survival in various advanced metastatic mouse tumor models

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Objectives: Patients who die from cancer succumb to advanced metastatic progression (AMP). While targeted therapies are available that address tumor cell derived regulators of metastasis, few therapeutics are being developed to address the molecular mechanisms of AMP. Our group has previously shown that vascular endothelial cell (VEC) PECAM-1 is a critical molecular master switch which regulates AMP by controlling the release of VEC-derived, paracrine growth factors that drive its progression. Anti-PECAM-1 monoclonal antibody (mAb) effectively and safely treats even pre-terminal cancers in AMP-bearing mice. The current experiments were performed to assess whether, to what extent and how widely targeting PECAM-1 can improve overall survival in mice bearing advanced metastases. Methods: Groups of wildtype (WT) C57Bl/6 mice, together with age and gender matched PECAM-1 knockout (KO) mice were intravenously injected with 25,000 murine B16-F10 melanoma cells, 30,000 murine EL4 lymphoma cells or 1,000,000 murine MC38 colon cancer cells. We then injected matched groups of PECAM-1 KO vs WT mice with 1,000,000 B16-F10 cells, to model maximally aggressive AMP. All groups were assessed for overall survival, using IACUC approved guidelines. Results: In all cases, overall survival (OS) was significantly prolonged in PECAM-1 KO vs WT controls (Kaplan-Meier ranged from p = 0.018 to p = 0.0002). Targeting microenvironmental PECAM-1 was as effective in increasing OS in mice receiving the very high tumor burden of 1,000,000 B16-F10 cells as in mice receiving 25,000 cells, further confirming the efficacy of targeting PECAM-1 against the most advanced models of metastasis that can be achieved preclinically. Furthermore, anti-PECAM-1 mAb-based therapy of B16-F10 metastase was as effective as the PECAM-1 KO genotype in increasing OS. Conclusion: To date, many approved mAb- and small molecule-inhibitor based targeted-therapies have shown limited abilities to either prolong OS as single agents, or to effectively treat multiple different solid tumor types. These results suggest that anti-PECAM-1 mAb therapy, which specifically targets VEC and paracrine factors they produce, has the potential to significantly increase OS in the setting of lethal advanced metastatic progression, independent of tumor type. Anti-PECAM-1 mAb therapy is as effective as a PECAM-1 knockout in improving OS. Phase 1 clinical trials are planned within 2 years. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2847. doi:1538-7445.AM2012-2847