Randall A. Allardyce

Short-term outcomes of the Australasian Randomized Clinical Study comparing laparoscopic and conventional open surgical treatments for colon cancer The ALCCaS Trial

Background:Laparoscopy has revolutionized many abdominal surgical procedures. Laparoscopic colectomy has become increasingly popular. The short- and long-term benefits and satisfactory surgical oncological treatment of colorectal cancer by laparoscopic-assisted resection remain topical. The long-term outcomes of all international randomized controlled trials are still awaited, and short-term outcomes are important in the interim. Methods:Between January 1998 and April 2005, a multicenter, prospective, randomized clinical trial in patients with colon cancer was conducted. Six hundred and one eligible patients were recruited by 33 surgeons from 31 Australian and New Zealand centers. Patients were allocated to colectomy by either laparoscopic-assisted surgery (n = 294) or open surgery (n = 298). Patient demographics and secondary end-points, such as operative and postoperative complications, length of hospital stay, and histopathological data, will be presented in this article. Analysis was by intention-to-treat. Survival will be reported only as the study matures. Results:Histopathological parameters were similar between the two groups, except in regard to distal resection margins. There was no statistically significant difference found in postoperative complications, reoperation rate, or perioperative mortality. Statistically significant differences in quicker return of gastrointestinal function and shorter hospital stay were identified in favor of laparoscopic-assisted resection. A statistically significant increased rate of infective complications was seen in cases converted from laparoscopic-assisted to open procedures but with no difference in reoperation or in-hospital mortality. Conclusions:Laparoscopic-assisted colonic resection gives significant improvements in return of gastrointestinal function and length of stay, with an increased operative time and no difference in the postoperative complication rate.

Tumor cell distribution following laparoscopic colectomy in a porcine model.

PURPOSE: A clinically relevant, laparoscopic colectomy model has been developed to quantify surgical practices that may affect the incidence of port wound tumor implantation. METHODS: Suspended51Cr-labeled, fixed HeLa cells were injected intraperitoneally into pigs before laparoscopic colectomies were performed with or without insufflation. Tumor cell contamination of instruments, ports, stability threads, and excised port wound margins was determined by gamma counting. RESULTS: Tumor cells were distributed throughout the peritoneal cavity, and the number detected at wound sites was directly related to number injected. Ports used by the operating surgeon had more cells than those used by the camera operator or assistant surgeon. Postoperative withdrawal of contaminated ports through abdominal wound was associated with an increase in port site contamination. Although the port site distribution of tumor cells was affected, mechanical elevation of abdominal wall did not eliminate contamination at any site. CONCLUSION: These results demonstrate application of the porcine model to test current surgical practices and measures that might be used perioperatively to reduce the numbers of intraperitoneal tumor cells or their distribution to specific sites during laparoscopic or open surgery.

Immune Response to an 18-Kilodalton Outer Membrane Antigen Identifies Lipoprotein 20 as a Helicobacter pylori Vaccine Candidate

ABSTRACT Experiments were performed using the standardized murine model ofHelicobacter pylori infection to determine the immunogenicity of H. pylori outer membrane vesicles in immune protection. These vesicles, which are naturally shed from the surface of the bacterium, induce a protective response when administered intragastrically to mice in the presence of cholera holotoxin, despite the absence of the urease enzyme and associated Hsp54 chaperonin. Immunoblotting identified a specific serum immunoglobulin G (IgG) response to an 18-kDa outer membrane protein in a significant number of immunized animals. This commonly expressed, immunodominant protein was subsequently identified as lipoprotein 20 (Lpp20). Hybridoma backpacks secreting an IgG1 subclass monoclonal antibody to Lpp20 were generated in H. pylori-infected mice and were found to significantly reduce bacterial numbers, providing evidence that this surface-exposed antigen is a true vaccine candidate and not merely an antigenic marker for successful, protective immunization.

Long-term outcomes of the Australasian randomized clinical trial comparing laparoscopic and conventional open surgical treatments for colon cancer: The Australasian Laparoscopic Colon Cancer Study Trial

Objective:We report a multicentered randomized controlled trial across Australia and New Zealand comparing laparoscopic-assisted colon resection (LCR) with open colon resection (OCR) for colon cancer. Background:Colon cancer is a significant worldwide health issue. This trial investigated whether the short-term benefits associated with LCR for colon cancer could be achieved safely, without survival disadvantages, in our region. Methods:A total of 601 patients with potentially curable colon cancer were randomized to receive LCR or OCR. Primary endpoints were 5-year overall survival, recurrence-free survival, and freedom from recurrence rates, compared using an intention-to-treat analysis. Results:On April 5, 2010, 587 eligible patients were followed for a median of 5.2 years (range, 1 week–11.4 years) with 5-year confirmed follow-up data for survival and recurrence on 567 (96.6%). Significant differences between the 2 trial groups were as follows: LCR patients were older at randomization, and their pathology specimens showed smaller distal resection margins; OCR patients had some worse pathology parameters, but there were no differences in disease stages. There were no significant differences between the LCR and OCR groups in 5-year follow-up of overall survival (77.7% vs 76.0%, P = 0.64), recurrence-free survival (72.7% vs 71.2%, P = 0.70), or freedom from recurrence (86.2% vs 85.6%, P = 0.85). Conclusions:In spite of some differences in short-term surrogate oncological markers, LCR was not inferior to OCR in direct measures of survival and disease recurrence. These findings emphasize the importance of long-term data in formulating evidence-based practice guidelines.

Operative factors affecting tumor cell distribution following laparoscopic colectomy in a porcine model

BACKGROUND: An increased risk of laparoscopic port wound tumor implantation in the presence of overt or covert abdominal malignancy has been identified. PURPOSE: A porcine laparoscopic colectomy model has been used to quantify the influence surgical practices may have on tumor cell implantation. METHODS:51Cr-labeled, fixed HeLa cells were injected intraperitoneally before surgery. Tumor cell contamination of instruments, ports, security threads, and excised wound margins was assessed by gamma counting. RESULTS: Greatest contamination occurred in ports used by the operating surgeon under pneumoperitoneum (64 percent of all port wound tumor cells) and mechanical elevation (76 percent). Gasless surgery in patients in the head-down position increased the rostral accumulation of tumor cells in the abdomen and right upper quadrant port wound by 330 and 176 percent, respectively. Under pneumoperitoneum, port movement was the major contributor to port leakage and wound contamination (21 percent of total recovered wound tumor cells per port). Tumor cells were not carried in aerosol form. Instrument passage and the withdrawal of security threads through the abdominal wall increased port wound contamination 430 and 263 percent, respectively, over pneumoperitoneum control ports. Preoperative lavage reduced by 61 percent, but did not eliminate, wound contamination. CONCLUSION: This porcine model may be used to evaluate surgical factors for the impact on port wound contamination.

COMPOSITION OF VOLATILE ORGANIC COMPOUNDS IN DIATHERMY PLUME AS DETECTED BY SELECTED ION FLOW TUBE MASS SPECTROMETRY

Background:  There is some evidence that surgical plume may pose a risk to health professionals, but the risks posed by volatile organic compounds have not been thoroughly investigated.

Iron influences the expression of Helicobacter pylori outer membrane vesicle-associated virulence factors.

Background Helicobacter pylori shed outer membrane vesicles (OMV) in vitro and in vivo. These OMV, which contain active VacA, provide a potential vehicle for the delivery of H. pylori virulence factors to the gastric mucosa. Objective To assess the influence of environmental iron levels on H. pylori OMV VacA and protease expression in vitro. Methods Three well‐characterized H. pylori type‐strains were grown for 72 h under normal (Brucella broth, 5% fetal calf serum) and iron‐limiting (Brucella broth, 5% fetal calf serum, 50 μmol/I deferoxamine) conditions. Following harvesting by differential centrifugation, the ratio of whole cells to OMV was determined. OMV VacA levels in response to iron availability were determined by ELISA and immunolabelling of washed bacteria. Protease activity was detected by zymography of OMV in the presence and absence of enzyme inhibitors and activators. HEp‐2 cells were used to assay for OMV‐associated cytopathogenic toxins. Results Decreased iron availability, which limited bacterial growth but not OMV release, also influenced the expression of OMV‐associated virulence factors. VacA levels were reduced, whereas two new proteolytic enzymes were expressed on these OMV. When an iron salt was added to counteract the effect of the deferoxamine, VacA levels were restored in the outer membrane and the proteolytic activity disappeared. Conclusions These results suggest that OMV release by H. pylori is influenced by environmental iron levels, and that the qualitative changes that occur in outer membrane composition may contribute to the clinical patterns of H. pylori ‐associated disease.

Dual silver staining to characterise Helicobacter spp. outer membrane components.

Helicobacter pylori is a bacterial pathogen, estimated to infect half the worlds population. The bacterium is the aetiological cause of gastritis, the common precursor for peptic ulcer disease and gastric cancer. Immunisation of at-risk individuals is the most cost-effective means of dealing with such a widespread pathogen. Potential vaccine candidates need to be identified and characterised. Conventional silver staining is commonly used for the sensitive detection of bacterial protein components separated by SDS-PAGE. Modified silver stains employing periodate oxidation have also been developed for the analysis of purified bacterial lipopolysaccharide. By using these methods in parallel, as a dual silver stain, bacterial fractions can be characterised in terms of protein and LPS content. Strain differences can also be readily identified by comparing protein and LPS profiles. When combined with differential immunoblotting, the dual silver stain is a useful analytical tool for characterising potential vaccine candidate antigens.

Australian and New Zealand study comparing laparoscopic and open surgeries for colon cancer in adults: organization and conduct

This article describes the initiation and implementation of the multicentre Australia and New Zealand prospective randomized controlled clinical study comparing laparoscopic and conventional open surgical treatments of right‐sided and left‐sided potentially curable colon cancer (Australasian Laparoscopic Colon Cancer Study). Six hundred and one adult patients were admitted with a clinical diagnosis of a single adenocarcinoma based on a physical examination and colonoscopy, barium enema or computed tomography scan and randomly allocated to either laparoscopic or open surgery. The primary aim of the study is to compare 5‐year mortality and tumour recurrence rates between the two groups. Secondary aims include comparisons of safety (intraoperative and early postoperative complications, wound site recurrence, postoperative recovery and 30‐day mortality), quality of life, in‐hospital costs and short‐term mortality and tumour recurrence. The data for 592 patients have been collected. There are currently 3141 person years of follow up. In all 370 patients have been assessed at 5 years. This study shows that large cooperative Australia–New Zealand surgical trials can and should be carried out to address significant clinical issues. When possible, coherence with similar, concurrent international trial protocols ensures broader analyses and applicability of results. It is important to recognize that special attention to sustained funding, surgeon credentialing, clinical protocol standardization, data management, publication policy and the protection of study credibility is required from the outset. The Australasian Laparoscopic Colon Cancer Study will achieve its aims with 5‐year assessments of all entered patients in March 2010.

Serum-derived IgG1-mediated immune exclusion as a mechanism of protection against H. pylori infection

The induction of protective immunity against Helicobacter challenge in a murine model was found to correlate with the magnitude of IgG (serum and gastric lavage) responsiveness to intra-nasal (i.n.) immunisation. IgG1-secreting hybridoma backpacks in Helicobacter pylori (H. pylori)-infected mice revealed serum transudation into the stomach. A Lpp20-specific monoclonal antibody was associated with significantly reduced H. pylori colonisation. Histology revealed aggregates of the remaining H. pylori in these mice, suggesting a role for IgG1-mediated immune exclusion of the bacteria. In vitro immunogold electron microscopy supported this hypothesis, but also suggested that a threshold of H. pylori-specific antibody needs to be maintained if immune exclusion by the host is to overcome immune evasion by the bacteria.