Inhibition of peritoneal tumor cell growth and implantation in laparoscopic surgery in a rat model

Comparing the cytotoxicity of taurolidine, mitomycin C, and oxaliplatin on the proliferation of in vitro colon carcinoma cells following pressurized intra-peritoneal aerosol chemotherapy (PIPAC)

BACKGROUND

Besides its known antibacterial effect commonly used in intraperitoneal lavage, taurolidine has been observed to possess antineoplastic properties. In order to analyse this antineoplastic potential in a palliative therapeutic setting, taurolidine (TN) was compared to mitomycin C (MMC) and oxaliplatin (OX), known antineoplastic agents which are routinely used in intraperitoneal applications, following pressurized intra-peritoneal aerosol chemotherapy (PIPAC).

METHODS

An in vitro model was established using a colon adenocarcinoma cell line (HT-29 human cells). Different experimental dosages of TN and combinations of TN, MMC, and OX were applied via PIPAC. To measure cell proliferation, a colorimetric tetrazolium reduction assay was utilized 24 h after PIPAC.

RESULTS

We demonstrated a cytotoxic effect of TN and OX (184 mg/150 mL, p < 0.01) on tumor cell growth. An increasing dosage of TN (from 0.5 g/100 mL to 0.75 g/150 mL) correlated with higher cell toxicity when compared to untreated cells (p < 0.05 and p < 0.01, respectively). PIPAC with OX and both OX and TN (0.5 g/100 mL) showed the same cytotoxic effect (p < 0.01). No significant impact was observed for MMC (14 mg/50 mL, p > 0.05) or MMC with OX (p > 0.05) applied via PIPAC.

CONCLUSIONS

The intraperitoneal application of TN is mostly limited to lavage procedures in cases of peritonitis. Our results indicate a substantial antineoplastic in vitro effect on colon carcinoma cells following PIPAC application. While this effect could be used in the palliative treatment of peritoneal metastases, further clinical studies are required to investigate the feasibility of TN application in such cases.

Innovative substance 2250 as a highly promising anti-neoplastic agent in malignant pancreatic carcinoma - in vitro and in vivo

BACKGROUND

Former studies already revealed the anti-neoplastic properties of the anti-infective agent Taurolidine (TRD) against many tumor species in vitro and in vivo. Its anti-proliferative and cell death inducing capacity is largely due to its main derivative Taurultam (TRLT). In this study it could be demonstrated, that substance 2250 - a newly defined innovative structural analogue of TRLT - exhibits an anti-neoplastic effect on malignant pancreatic carcinoma in vitro and in vivo.

METHODS

The anti-neoplastic potential of substance 2250 as well as its mode of action was demonstrated in extensive in vitro analysis, followed by successful and effective in vivo testings, using xenograft models derived from established pancreatic cancer cell lines as well as patient derived tissue.

RESULTS

Our functional analysis regarding the role of oxidative stress (ROS) and caspase activated apoptosis showed, that ROS driven programmed cell death (PCD) is the major mechanisms induced by substance 2250 in pancreatic carcinoma. What is strongly relevant towards clinical practice is especially the observed inhibition of patient derived pancreatic cancer tumor growth in mice treated with this new substance in combination with its sharply higher metabolic stability.

CONCLUSION

These encouraging results provide new therapeutical opportunities in pancreatic cancer treatment and build the basis for further functional analysis as well as first clinical studies for this promising agent.

Adhesion molecules in peritoneal dissemination: function, prognostic relevance and therapeutic options

Peritoneal dissemination is diagnosed in 10–25 % of colorectal cancer patients. Selected patients are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. For these patients, earlier diagnosis, optimised selection criteria and a personalised approach are warranted. Biomarkers could play a crucial role here. However, little is known about possible candidates. Considering tumour cell adhesion as a key step in peritoneal dissemination, we aim to provide an overview of the functional importance of adhesion molecules in peritoneal dissemination and discuss the prognostic, diagnostic and therapeutic options of these candidate biomarkers. A systematic literature search was conducted according to the PRISMA guidelines. In 132 in vitro, ex vivo and in vivo studies published between 1995 and 2013, we identified twelve possibly relevant adhesion molecules in various cancers that disseminate peritoneally. The most studied molecules in tumour cell adhesion are integrin α2β1, CD44 s and MUC16. Furthermore, L1CAM, EpCAM, MUC1, sLe^x and Le^x, chemokine receptors, Betaig-H3 and uPAR might be of clinical importance. ICAM1 was found to be less relevant in tumour cell adhesion in the context of peritoneal metastases. Based on currently available data, sLe^a and MUC16 are the most promising prognostic biomarkers for colorectal peritoneal metastases that may help improve patient selection. Different adhesion molecules appear expressed in haematogenous and transcoelomic spread, indicating two different attachment processes. However, our extensive assessment of available literature reveals that knowledge on metastasis-specific genes and their possible candidates is far from complete.

Animal models of colorectal peritoneal metastasis

Colorectal cancer remains an important cause of mortality worldwide. The presence of peritoneal carcinomatosis (PC) causes significant symptoms and is notoriously difficult to treat. Therefore, informative preclinical research into the mechanisms and possible novel treatment options of colorectal PC is essential in order to improve the prognostic outlook in these patients. Several syngeneic and xenograft animal models of colorectal PC were established, studying a wide range of experimental procedures and substances. Regrettably, more sophisticated models such as those giving rise to spontaneous PC or involving genetically engineered mice are lacking. Here, we provide an overview of all reported colorectal PC animal models and briefly discuss their use, strengths, and limitations.

Redox-directed cancer therapeutics: Taurolidine and Piperlongumine as broadly effective antineoplastic agents (review)

Targeting the oxygen stress response pathway is considered a promising strategy to exert antineoplastic activity in a broad spectrum of tumor types. Supporting this view, we summarize the mechanism of action of Taurolidine and Piperlongumine, two antineoplastic agents with strikingly broad tumor selectivity. Taurolidine enhances the oxidative stress (ROS) selectively in tumor cells. Its cytotoxicity for various tumor cells in vitro and in vivo, which includes tumor stem cells, is based on the induction of programmed cell death, largely via apoptosis but also necroptosis and autophagy. The redox-directed mechanism of action of Taurolidine is apparent from the finding that reducing agents e.g., N-acetylcysteine or glutathione impair its cytotoxicity, while its effectiveness is enhanced by agents which inhibit the cellular anti‑oxidant capacity. A similar redox-directed antineoplastic action is shown by Piperlongumine, a recently described experimental drug of plant origin. Taurolidine is particularly advantageous in surgical oncology as this taurine-derivative can be applied perioperatively or systemically with good tolerability as shown in initial clinical applications.

The antineoplastic antibiotic taurolidine promotes lung and liver metastasis in two syngeneic osteosarcoma mouse models and exhibits severe liver toxicity

Osteosarcoma (OS) is the most frequent primary bone tumor. Despite multiagent neoadjuvant chemotherapy, patients with metastatic disease have a poor prognosis. Moreover, currently used chemotherapeutics have severe toxic side effects. Thus, novel agents with improved antimetastatic activity and reduced toxicity are needed. Taurolidine, a broad-spectrum antimicrobial, has recently been shown to have antineoplastic properties against a variety of tumors and low systemic toxicity. Consequently, we investigated in our study the antineoplastic potential of taurolidine against OS in two different mouse models. Although both OS cell lines, K7M2 and LM8, were sensitive for the compound in vitro, intraperitoneal application of taurolidine failed to inhibit primary tumor growth. Moreover, it enhanced the metastatic load in both models 1.7- to 20-fold and caused severe liver deformations and up to 40% mortality. Thus, systemic toxicity was further investigated in tumor-free mice histologically, by electron microscopy and by measurements of representative liver enzymes. Taurolidine dose-dependent fibrous thickening of the liver capsule and adhesions and atrophies of the liver lobes were comparable in healthy and tumor-bearing mice. Liver toxicity was further indicated by up to eightfold elevated levels of the liver enzymes alanine transaminase, aspartate transaminase and GLDH in the circulation. Ultrastructural analysis of affected liver tissue showed swollen mitochondria with cristolysis and numerous lipid vacuoles in the cytoplasm of hepatocytes. The findings of our study question the applicability of taurolidine for OS treatment and may suggest the need for caution regarding the widespread clinical use of taurolidine as an antineoplastic agent.

Low incidence of port-site metastases after laparoscopic staging of uterine cancer

OBJECTIVE

To estimate the incidence of clinically detected port-site metastases (PSM) in patients with endometrial and cervical cancer treated at two gynecologic oncology services with extensive experience.

METHODS

All eligible uterine cancer patients laparoscopically staged at Centre Oscar Lambret in Lille and Institut Claudius Regaud in Toulouse, France, were reviewed. MEDLINE database was searched to identify articles on PSM after laparoscopic procedures for cervical and endometrial cancer.

RESULTS

During the study period, 1216 laparoscopic procedures for uterine cancer were performed. 921 patients underwent laparoscopic staging for cervical cancer and 295 for endometrial cancer. The overall incidence of PSM in our institutions was 0.4% per procedure (5 patients), and the incidence of PSM after laparoscopy for cervical and endometrial cancer was 0.43% and 0.33%, respectively. Excluding patients with peritoneal carcinomatosis, the rate of port-site recurrence in our series lowered to 0.16%, and the rate of isolated PSM to 0%. The median time to the development of PSM was 8 months (range 6-48), the median overall survival from diagnosis for all patients was 26 months (range 7-30), and median survival from recurrence was 5 months (range 1-20).

CONCLUSION

Although PSM is recognized as a complication of laparoscopy for ovarian cancer. PSM is a rare complication of laparoscopic staging for endometrial and cervical cancer. The majority of patients with PSM presented with associated synchronous disease. The incidence of isolated PSM can be maintained virtually to 0% by an adequate operative technique. We believe that PSM in patients with uterine cancer cannot be used as an argument against laparoscopic staging in uterine cancer.

Oral administration of the anti-proliferative substance taurolidine has no impact on dextran sulfate sodium induced colitis-associated carcinogenesis in mice

Background:

New chemopreventive strategies for ulcerative colitis (UC)-associated dysplasia and cancer have to be evaluated. Taurolidine (TRD) has anti-inflammatory, anti-proliferative and anti-neoplastic properties with almost absent toxicity. The aim of the study was to determine whether TRD decreases dysplasia in the well-characterized Dextran Sulfate Sodium – Azoxymethane (DSS-AOM) animal model for UC-associated carcinogenesis.

Material and Methods:

The DSS-AOM model of carcinogenesis was induced in female inbred C57BL/6 mice. Half of the mice were treated with TRD, the other served as control. After 100 days macroscopic, histological and immunhistochemical (β-Catenin, E-Cadherin, SOX9, Ki-67, Cyclin-D1) examination of the colon was performed.

Results:

Incidence, multiplicity, grading and growth pattern of adenomas did not differ significantly between TRD and control group. In all animals, inflammatory changes were absent. Immunhistochemistry revealed increased expression of Ki-67, β-catenin, SOX9 and Cyclin-D1 in adenomas compared to normal mucosa – without significant difference between TRD and control treatment.

Conclusion:

Oral administration of TRD has no impact on DSS-induced colitis-associated carcinogenesis. However, SOX9 and Cyclin-D1 representing key members of the Wnt pathway have not yet been described in the DSS-AOM model of carcinogenesis – underlining the importance of this oncogenic pathway in this setting.

Taurolidine antiadhesive properties on interaction with E. coli; its transformation in biological environment and interaction with bacteria cell wall

The taurine amino-acid derivative, taurolidine, bis-(1,1-dioxoperhydro-1,2,4-thiabiazinyl-4)methane, shows broad antibacterial action against gram-positive and gram-negative bacteria, mycobacteria and some clinically relevant fungi. It inhibits, in vitro, the adherence of Escherichia coli and Staphylococcus aureus to human epithelial and fibroblast cells. Taurolidine is unstable in aqueous solution and breaks down into derivatives which are thought to be responsible for the biological activity. To understand the taurolidine antibacterial mechanism of action, we provide the experimental single crystal X-ray diffraction results together with theoretical methods to characterize the hydrolysis/decomposition reactions of taurolidine. The crystal structure features two independent molecules linked through intermolecular H-bonds with one of them somewhat positively charged. Taurolidine in a biological environment exists in equilibrium with taurultam derivatives and this is described theoretically as a 2-step process without an energy barrier: formation of cationic taurolidine followed by a nucleophilic attack of O(hydroxyl) on the exocyclic C(methylene). A concerted mechanism describes the further hydrolysis of the taurolidine derivative methylol-taurultam. The interaction of methylol-taurultam with the diaminopimelic NH(2) group in the E. coli bacteria cell wall (peptidoglycan) has a negative DeltaG value (-38.2 kcal/mol) but a high energy barrier (45.8 kcal/mol) suggesting no reactivity. On the contrary, taurolidine docking into E. coli fimbriae protein, responsible for bacteria adhesion to the bladder epithelium, shows it has higher affinity than mannose (the natural substrate), whereas methylol-taurultam and taurultam are less tightly bound. Since taurolidine is readily available because it is administered in high doses after peritonitis surgery, it may successfully compete with mannose explaining its effectiveness against bacterial infections at laparoscopic lesions.

Influence of intraperitoneal application of taurolidine/heparin on expression of adhesion molecules and colon cancer in rats undergoing laparoscopy

BACKGROUND

Recent experimental studies have shown that intraperitoneal administration of taurolidine/heparin causes a reduction of local tumor growth after laparoscopy in rat models. It might be that the anti-adherent activities of these agents are responsible for this effect. In this study we investigated the adhesion molecules E-cadherin, beta1-integrin, and CD44.

MATERIALS AND METHODS

Following a 10,000 colon adenocarcinoma cells' (DHD/K12/TRb) intraperitoneal application a cecum resection and a partial parietal peritoneum resection (1 x 1 cm) were performed using a three trocar technique in 30 BD IX rats. After randomization in two groups, the cecum suture line and the parietal peritoneal defect were either lavaged with 1 mL of 0.5% taurolidine/10 IU heparin or with equal amounts of 0.9% normal saline solution. Rats were sacrificed four weeks after operation and total tumor growth was determined. E-cadherin, beta1-integrin, and CD44 were assessed immunohistochemically on the tumor tissue.

RESULTS

The expression of E-cadherin was significantly reduced to 46.7% (complete loss of staining) in the taurolidine/heparin group. Although no significant difference was detected concerning the beta1-integrin and CD44 expression, a slightly reduced expression level with 26.7% of negative staining in metastases of the taurolidine/heparin group was observed. The total tumor weight (171.1 +/- 181.2 mg) as well as the total number of tumor lesions was also reduced by the substances compared to the control group (283.2 +/- 91.4 mg).

CONCLUSIONS

Taurolidine/heparin led to a significant reduction of local tumor growth. Additionally a reduction of the expression of E-cadherin was observed. However, the biological behavior of this molecule is multivariant, controversial and still unclear. Further studies should elucidate its role in the epithelial tumor genesis.

Inhibition of ovarian cancer growth and implantation by paclitaxel after laparoscopic surgery in a mouse model

OBJECTIVE

We used an established experimental model to evaluate the influence of intraperitoneal chemotherapy on the generation of laparoscopy-associated metastases and the effectiveness of chemotherapy.

STUDY DESIGN

Twenty-four nude mice underwent laparoscopy with carbon dioxide insufflation and the instillation of a tumor cell suspension with or without paclitaxel into the peritoneal cavity. Mice were allocated to 1 of the following groups (8 mice to each group): (1) controls; (2) paclitaxel given during the operation; (3) paclitaxel given after the operation. Mice were killed 30 days after the procedure, and the peritoneal cavity and port sites were examined for the presence of tumors.

RESULTS

Tumor implantation and port-site metastases were reduced more by the intraoperative intraperitoneal administration of paclitaxel during the operation than by administration after the operation.

CONCLUSION

Intraoperative intraperitoneal administration of paclitaxel may decrease significantly the occurrence of port-site metastasis and intraperitoneal dissemination in an animal study.

Mechanisms of heparin induced anti-cancer activity in experimental cancer models

BACKGROUND

Retrospective analyses of clinical trials and prospective clinical studies have suggested that heparins may have an effect on cancer survival. This putative anti-cancer activity of heparins is supported by data from studies in animal tumour models.

OBJECTIVE

To clarify the various potential mechanisms of heparin anti-cancer activity we evaluated the data from pre-clinical studies in which heparins have been tested as anti-cancer therapy.

METHODS

Pre-clinical studies, published between 1960 and 2005 were assessed. Data were collected on the type and dose of heparin used, duration of exposure to heparin, interval between heparin administration and cancer cell inoculation, and the animal tumour model used. In addition, a distinction was made in the analysis between heparin effects on the primary tumour or on established metastases and effects on the metastatic potential of infused cells.

RESULTS

Heparins seemed to affect the formation of metastasis rather than the growth of primary tumours. Chemically modified heparins with no or limited anticoagulant activity also showed anti-metastatic properties. Possible mechanisms to explain the effects on the process of metastases include inhibition of blood coagulation, inhibition of cancer cell-platelet and -endothelial interactions by selectin inhibition and inhibition of cell invasion and angiogenesis.

CONCLUSION

The anti-cancer activity of heparins depends more on inhibition of metastasis formation than on the effects on primary tumour growth. These effects are probably related to both coagulation and non-coagulation dependent factors. For a definitive proof of the anti-cancer activity of heparins in the clinic, prospective randomized trials especially in patients with early metastatic disease or in the adjuvant setting are urgently needed.

Minimally invasive management of colon cancer

One of the most controversial issues in minimally invasive surgery has been the implementation of laparoscopic techniques for the curative resection of colorectal malignancies. Initial concerns included the potential violation of oncologic principles, the effects of carbon dioxide, and the phenomenon of port site tumor recurrence. Basic science research and large randomized controlled trials are now demonstrating that these fears were unjustified. Long-term outcomes of laparoscopic colon resection compared with open colon resection for malignancy are comparable, and there may even be a survival benefit for a subset of patients who undergo laparoscopic resection.

Taurolidine–a new drug with anti-tumor and anti-angiogenic effects

Taurolidine [bis(1,1-dioxoperhydro-1,2,4-thiadiazinyl-4)-methane (TRD)], a product derived from the aminosulfoacid taurin, was first described as an anti-bacterial substance. It was mainly used in the treatment of patients with peritonis as well as antiendoxic agent in patients with systematic inflammatory response syndrome. Meanwhile, quite interesting new experimental findings elucidated several new mechanisms concerning not only antibiotic but also anti-tumor effects. TRD significantly reduces the pathogenicity of prokaryotes, leading to a degeneration of the bacterial wall, and binds free lipoplysaccharides (LPSs) and exotoxins. Furthermore syntheses of tumor necrosis factor-a and interleukin-1b are reduced in LPS-stimulated human macrophages in a dose dependent manner. Tumor angiogenesis is promoted by enhanced expression of all these endogenous angiogenic factors, indicating an anti-angiogenetic effect of TRD. Tumor angiogenesis has a key role in tumor growth. TRD additionally inhibits tumor cell growth by a mitochondrial cytochrome c-dependent apoptotic mechanism, has a direct and elective effect on glial and neuronal brain tumor cells via Fas-ligand-mediated cell death, and inhibits protein synthesis at an early phase of translation, which might explain its various apoptotic effects. Subsequent to these experimental observations, TRD has shown encouraging clinical results after intravenous administration in patients with gastrointestinal malignancies and tumors of the central nerve system. A remarkable experimental observation that comes to complete the above-mentioned findings is the low toxicity on leukopoiesis and erythropoiesis as well as on kidney and liver function in animal models. Several other data confirm low toxicity of the agent after its clinical administration in humans. Prospective clinical studies are currently investigating the efficacy of TRD on local and metastatic tumor growth in different malignancies.

Peritoneal nebulizer: a novel technique for delivering intraperitoneal therapeutics in laparoscopic surgery to prevent locoregional recurrence

BACKGROUND

Peritoneal involvement is a significant issue in the treatment of gastrointestinal malignancies. Current statistics indicate that after surgical intervention, up to 20% of patients will present with locoregional metastasis. The ability to inhibit initial tumor adhesion to the mesothelial lining of the peritoneum may be considered critical in the inhibition of tumor development. This article describes, the use of a novel nebulizer system capable of delivering high-concentration, low-dose therapeutics to the peritoneal cavity.

METHODS

For this study, 30 male WAG rats were inoculated with CC531 colorectal tumor cells. The rats were randomized into three groups: control group (n = 10), heparin-treated group (n = 10), and high-molecular-weight hyaluronan-treated group (n = 10). A peritoneal cancer index was used to determine tumor burden at 15 days. Analysis of variance (ANOVA) was used to compare multiple group means.

RESULTS

Nebulization therapy was performed without any complication in the cohort. Heparin inhibited macroscopic intraperitoneal tumor growth completely (p = 0.0001) without affecting tumor cell viability. The introduction of hyaluronan attenuated both tumor size and distribution, was compared with the control group (p = 0.002).

CONCLUSION

Nebulized heparin and hyaluronic acid using a novel nebulization technique attenuates peritoneal tumor growth after laparoscopic surgery. The technique itself is easy to use and safe.

The effects of taurolidine, a novel antineoplastic agent, on human malignant mesothelioma

PURPOSE

Malignant mesothelioma (MM) is a cancer with uniformly poor responses to current therapeutic regimens. This study evaluates whether taurolidine, a novel antineoplastic agent, is effective against human MM cell lines and a murine model of human MM.

EXPERIMENTAL DESIGN

Cell growth inhibition and viability assays were performed on REN, LRK, and H28 cell lines after 24-72-h exposure to 0-200 microm taurolidine. Cell cycle analysis with annexin-V binding, terminal deoxynucleotidyl transferase-mediated nick end labeling assay, electron microscopy, and response to the general caspase inhibitor z-VAD-fmk were performed on MM cell lines after 24-72-h exposure to 50-150 microm taurolidine. Athymic mice were given i.p. injections of 20 x 10(6) REN cells, followed by i.p. taurolidine (17.5 or 20 mg), 3 days/week for up to 3 weeks. Tumors were assessed at day 30. All statistical tests were two-sided.

RESULTS

A 72-h exposure of MM cells to taurolidine showed IC50 of 28-42.7 microm and 50% viability at 49.8-135 microm. Annexin V assay for apoptosis revealed significant increases in annexin binding after 24-72-h exposure to 50-150 microm taurolidine (P <0.05), which was significantly inhibited by z-VAD (P <0.05). MM cells exposed to 50-150 microm taurolidine for 24-72 h showed terminal deoxynucleotidyl transferase-mediated nick end labeling staining consistent with apoptosis, as well as structural evidence of apoptosis via electron microscopy. In vivo, there were significant tumor reductions (62 to >99% reduction) for all dosage regimens compared with untreated controls (P <0.001). In addition, all control animals exhibited ascites and diaphragmatic tumors while treated animals did not.

CONCLUSIONS

Taurolidine has significant antineoplastic activity against MM in vitro and in vivo, in part, due to tumor cell apoptosis. These findings warrant further study for potential clinical usefulness.

Effect of carbon dioxide pneumoperitoneum and wound closure technique on port site tumor implantation in a rat model

BACKGROUND

The purpose of this study was to evaluate the effects of carbon dioxide (CO2) pneumoperitoneum and wound closure technique on port site tumor implantation.

METHODS

A standard quantity of rat mammary adenocarcinoma (SMT2A)was allowed to grow in a flank incision in Wistar-Furth rats (n = 90) for 14 days. Thereafter, 1-cm incisions were made in each animal in three quadrants. There were six control animals. The experimental animals were divided into a 60-min CO2 pneumoperitoneum group (n = 42) and a no pneumoperitoneum (n = 42) group. The flank tumor was lacerated transabdominally in the experimental groups. The three wound sites were randomized to closure of (a) skin; (b) skin and fascia; and (c) skin, fascia, and peritoneum. The abdominal wounds were harvested en bloc on postoperative day 7.

RESULTS

Histologic comparison of the port sites in the pneumoperitoneum and no-pneumoperitoneum groups did not demonstrate a statistically significant difference in tumor implantation for any of the closure methods. Evaluation of the closure techniques showed no statistical difference between the pneumoperitoneum group and the no-pneumoperitoneum group in the incidence of port site tumor implantation. Within the no-pneumoperitoneum group, there was a significant increase (p = 0.03) in tumor implantation with skin closure alone vs all three layers. Additionally, when we compared all groups by closure technique, the rate of tumor implantation was found to be significantly higher (p = 0.01) for skin closure alone vs closure of all three layers.

CONCLUSIONS

This study suggests that closure technique may influence the rate of port site tumor implantation. The use of a CO2 pneumoperitoneum did not alter the incidence of port site tumor implantation at 7 days postoperatively.

Irrigation of port sites: prevention of port site metastases?

INTRODUCTION

Port site metastases can occur when free viable tumor cells implant at trocar wounds. Irrigation of port sites with cytotoxic agents has been suggested to prevent port site metastases. The objective of this study is to assess whether tumor growth at port sites can be reduced by irrigation of these port sites.

METHODS

WAG rats were insufflated with CO(2) for 20 minutes and 5 x 10(5) CC531 tumor cells were injected intraperitoneally. Port sites were irrigated after completion of the pneumoperitoneum with povidone-iodine, a mixture of taurolidine and heparin, or sodium chloride. Controls did not undergo any irrigation of port sites. In experiment 1, all 16 rats had all 4 irrigation modalities. In experiment 2, four groups of 20 rats had one type of irrigation on two trocar wounds. Tumor growth was evaluated 4 weeks after the procedure.

RESULTS

No difference in tumor growth at trocar wounds was found between any type of irrigation and controls in both experiments.

CONCLUSION

In this experimental model, no beneficial or adverse effects of irrigation of port sites could be shown.

Port site metastases

BACKGROUND

Concerns about port site metastases have limited the application of minimally invasive surgery for intra-abdominal malignancies. The purpose of this review article was to summarize the current literature regarding port site metastases.

METHODS

A Medline search identified >100 articles in English published during the last 15 years regarding the history, incidence, etiology, and prevention of port site metastases. These articles were reviewed and are summarized.

RESULTS

The incidence of port site metastases, initially thought to be as high as 21%, is now thought to be closer to the incidence of wound metastases after open surgery. Multiple etiologic factors have been studied including direct wound contamination, surgical technique, effects of carbon dioxide pneumoperitoneum, and changes in host immune response. Various preventive measures have been proposed.

CONCLUSIONS

Port site metastases are a well-documented and devastating complication after laparoscopic resection of intra-abdominal malignancies. Although the etiology is not yet understood, a number of factors are contributory. All efforts should be made to prevent port site metastases.

Laparoscopic colon resection for colon cancer

INTRODUCTION

Laparoscopic colon resection for cancer is as yet an unproven operation. This review article summarizes current data on the topic.

METHODS

A Medline review identified articles published since 1990 summarizing patients with potentially curable colon cancer who underwent a laparoscopic-assisted colon resection. Only articles that were randomized or had a control group with historical or matched open cases were used.

RESULTS

Very few prospective randomized controls exist. Several clinical trials are under way with one completed. Data thus far support some patient benefits with a laparoscopic approach. No differences in morbidity, oncologic data, or survival appear to exist.

CONCLUSIONS

The results of ongoing clinical trials are still needed to further evaluate the role of laparoscopic assisted colon resection in patients with potentially curable colon cancer.

Laparoscopic port-site metastases: etiology and prevention

OBJECTIVE

The purpose of this article is to summarize current hypotheses for the possible sources of laparoscopic port-site metastasis, to review the results of experimental models that support such hypotheses, and to discuss the potential options for preventing these metastases.

METHODS

We performed a Medline search to identify in vitro and in vivo studies and clinical trials that analyzed port-site metastases associated with laparoscopic surgery. We report the incidence of port-site metastases and causative factors associated with this condition.

RESULTS

The estimated incidence of port-site metastases in all patients undergoing laparoscopic surgery for malignant disease is approximately 1-2%. Multiple factors are associated with this complication. Among the most common proposed etiologies are the wound implantations caused by the surgical technique and instrumentation; the leakage of insufflation gas through the ports, known as the "chimney effect"; and the impact of pneumoperitoneum on local immune reactions. Several preventive measures, have been suggested, including careful patient selection, lavage of the peritoneal cavity as well as of the port wounds with cytotoxic agents, and modifications of surgical technique.

CONCLUSIONS

Only through the results of well-conducted large multi-institutional prospective randomized trials will we learn not only the true incidence of port-site metastases, but also the potential factors that lead to the occurrence of this complication.

Low-molecular-weight heparin (reviparin) diminishes tumor cell adhesion and invasion in vitro, and decreases intraperitoneal growth of colonadeno-carcinoma cells in rats after laparoscopy

BACKGROUND

Metastases, adhesion and invasion of tumor cells involve a cascade of complex phenomena, which potentially can be affected by glycosaminoglycans. We studied the influence of a low-molecular-weight heparin, reviparin, on the intraabdominal tumor growth in rats undergoing laparoscopy. We also studied cytotoxicity, anti-adhesive, and anti-invasive effects of reviparin in vitro using adenocarcinoma cells CC531.

METHODS

In vitro assays: Adhesion of 1 x 10(5) CC531 adenocarcinoma cells onto microtiter plates coated with 10 microg/ml collagen type I or 10 microg/ml Matrigel was studied in the presence of 0.55; 1.10 and 2.76 mg/ml reviparin, and compared to saline. The cytotoxicity of 1 x 10(4) adenocarcinoma cells was studied in a similar assay. Transwell dual chambers with polycarbonate filters coated with 100 microg/cm2 Matrigel were used to investigate the effect of 0.55; 1.10 and 2.76 mg/ml reviparin on the invasion of 1 x 10(5) adenocarcinoma cells/ml. In vivo experiments: CC531 adenocarcinoma cells (5 x 10(6) cells/ml) were intraperitoneally applied to Wistar Albino Glaxo rats (n=150, Harlan, Germany) with a median weight of 278 g. The rats were divided into 15 groups with 10 animals in each group, underwent laparoscopy, and 1 ml saline containing 0, 0.5, 2.0, 4.0, and 10 mg reviparin per kg b.w. was introduced for intraperitoneal lavage or s.c. After 21 days the animals underwent an autopsy, and the tumor weight was determined.

RESULTS

In vitro experiments: We found a highly significant inhibition of tumor cell adhesion and invasion (p<0.001) by all reviparin concentrations used in the assays. There was no effect of reviparin on the viability of cells in the cytoxicity assay. In vivo experiments: We found that application of 4.0 and 10.0 mg/kg b.w., but not 0.5 or 2.0 mg/kg b.w. significantly (p<0.01) decreased the tumor mass compared to controls, receiving only saline. This effect was most pronounced after the combined i.p. and s.c. application, whereas after a sole i.p. application, only the highest dose of 10 mg/kg b.w. caused a significant inhibition of tumor growth.

CONCLUSION

Low-molecular-weight heparin, reviparin, given in combination of i.p. lavage and s.c. injections, significantly diminishes intraabdominal tumor growth of CC531 adenocarcinoma cells in rats undergoing laparoscopy. This may offer additional therapeutic options for patients undergoing laparoscopic cancer surgery.

Port site metastases in urological laparoscopic surgery

PURPOSE

Laparoscopic surgery is rapidly gaining widespread acceptance among urologists, including extensive application in malignant conditions. However, untoward occurrences of port site metastases have not eluded to urological applications. This up-to-date review on port site metastases in urology delineates possible contributing factors and describes techniques to prevent it.

MATERIALS AND METHODS

We comprehensively reviewed published experimental and clinical studies with special emphasis on the incidence, pathophysiology and prevention of port site metastases.

RESULTS

Nine cases of port site metastases after urological laparoscopy have been described in clinical and experimental studies. Etiological factors include natural malignant disease behavior, host immune status, local wound factors, laparoscopy related factors such as aerosolization of tumor cells (the use of gas, type of gas, insufflation and desufflation, and pneumoperitoneum) and sufficient technical experience of the surgeons and operating team (adequate laparoscopic equipment, skill, minimal handling of the tumor, surgical manipulation and wound contamination during instruments change, organ morcellation and specimen removal).

CONCLUSIONS

Port site metastases is a multifactorial phenomenon with an as yet undetermined incidence. The problem is influenced to some extent by surgeon and operating team experience and, therefore, it could be partially prevented. The suggested preventive steps are avoiding laparoscopic surgery when there are ascites, trocar fixation to prevent dislodgment, avoiding gas leakage along and around the trocar, sufficient technical readiness of the operating team (adequate laparoscopic equipment and technique, minimal handling and avoiding tumor boundary violation of the tumor), using a bag for specimen removal, placing drainage when needed before desufflation, povidone-iodine irrigation of instruments, trocars and port site wounds, and suturing 10 mm. and larger trocar wounds.

The effect of Taurolidine on adherent and floating subpopulations of melanoma cells

The annual incidence of malignant melanoma is estimated at 10-12 per 100000 inhabitants in countries of Central Europe and the US, with more recent estimates showing a dramatic upward trend. Taurolidine (Carter/Wallace, Cranberry, NJ) is a novel, potentially effective, antitumor chemotherapeutic agent. We hypothesized that Taurolidine could inhibit the growth, induce apoptosis, affect the cell cycle and change morphology of melanoma cells. We expected this process to be different in adherent and floating subpopulations that may be reflective of solid tumors and their metastases. Analysis of MNT-1 human and B16F10 murine melanoma cells showed that at 72 h the IC(50) of Taurolidine was 25.4+/-3.3 microM for MNT-1 human melanoma cells and 30.9+/-3.6 microM for B16F10 murine melanoma cells. Taurolidine induced DNA fragmentation of melanoma cells in a dose-dependent manner. Taurolidine (75 and 100 microM) induced 52-97% Annexin-V binding (apoptosis), respectively. Evaluation of cell cycle after 72 h exposure to Taurolidine (0-100 microM) revealed that the percentage of melanoma cells in S phase increased from 27 to 40% in the adherent subpopulation and from 33 to 49% in the floating subpopulation. Phase contrast microscopy revealed a marked swelling of melanoma cells and decreasing cell numbers in adherent subpopulation starting at 24 h with 25 microM Taurolidine. Shrinkage of cells dominated at 75-100 microM Taurolidine. Using Cytospin assay in the floating population, we observed swelling of melanoma cells induced by 25-100 micro Taurolidine and appearance of giant (multinuclear) forms resulting from exposure to 75-100 micro Taurolidine. Some floating cells with normal morphology were observed with low concentrations of Taurolidine (0-25 microM). These data show that effects of Taurolidine may be different in adherent and floating subpopulations of melanoma cells. More importantly, floating subpopulations that may contain some viable melanoma cells, may be reflective of potential metastasis after treatment of solid tumors in vivo.

[In vitro effect of taurolidine on squamous cell carcinoma in the oral cavity]

Taurolidine (Taurolin) is a derivative of the amino acid taurine, successfully used in the treatment of peritonitis. In vitro and in vivo studies have shown that taurolidine inhibits cell proliferation and induces apoptosis in a variety of tumor cell lines. At present there are no published studies on the use of taurolidine in the treatment of squamous cell carcinoma. Our aim was to examine the inhibition of cell proliferation and induction of apoptosis in cell lines SCC 4 and SCC 15 treated with taurolidine in concentrations of 0.01%, 0.1%, and 0.5%. Analogue to the present investigations on adenocarcinoma cell lines, we used toxic antiseptic povidone iodine in the same concentration as for the reference group. Untreated cells were used as a control group. The cells were incubated with taurolidine or povidone iodine once for 2 h at 37 degrees C in 5% CO(2). Cell proliferation was assessed using WST-1 labeling kit after 3, 24, 48, 72, and 96 h. The additional measurement of cell apoptosis was examined using ELISA(PLUS) cell death detection kit and performed after 0, 24, and 48 h. The findings showed a significant inhibition of cell proliferation and induction of apoptosis in taurolidine-treated cells SCC 4 and SCC 15 in contrast to the reference group treated with povidone iodine or the untreated control group.

Intraperitoneal hypothermia during surgery enhances postoperative tumor growth

BACKGROUND

Recent work has shown that intraoperative hypothermia is a significant source of surgical trauma, with wide-ranging physiological and immunological sequelae. The aim of this study was to examine the effects of intraperitoneal hypothermia during laparoscopy on tumor growth in an animal model.

METHODS

Thirty WAG rats were randomized to undergo anesthesia alone (n = 10), insufflation with cold carbon dioxide (CO2) (n = 10), or insufflation with warm CO2 (n = 10). During insufflation, 1 x 105/ml CC531s colon cancer cells in suspension were injected into the peritoneal cavity. The control group was anesthetized and tumor cells were injected without insufflation. After 3 weeks, total tumor weight and the extent of tumor spread, as assessed by the modified Peritoneal Cancer Index (PCI), were compared at autopsy.

RESULTS

Laparoscopy with cold CO2 resulted in a significant reduction in local and core body temperatures (p <0.05). Tumor growth in both groups that underwent CO2 pneumoperitoneum was significantly increased compared with the group that did not (p <0.0001, control vs warm CO2 and cold CO2). There was significantly more tumor growth in the rats insufflated with unwarmed CO2 than in the normothermic group (mean total tumor 0.01 g +/- 0.03 vs. 0.043 g +/- 0.07; p = 0.025 Mann-Whitney U test). Tumor spread as shown by the PCI scores was less in the warm gas group than it was in the animals insufflated with cold gas (151 vs 266).

CONCLUSIONS

These data demonstrate that the peritoneal insufflation of CO2 enhances tumor growth and that the prevention of perioperative hypothermia during laparoscopy attenuates tumor growth. This effect may be partially mediated by the increased peritoneal trauma that results from insufflation with cold gas.

Influence of intraperitoneal and systemic application of taurolidine and taurolidine/heparin during laparoscopy on intraperitoneal and subcutaneous tumour growth in rats

BACKGROUND

Recent clinical and experimental studies investigated the problem and possible pathomechanisms of portsite metastases after laparoscopic resection of malignant tumours. A generally accepted approach to prevent these tumour implantations does not exist so far.

METHODS

After subcutaneous and intraperitoneal injection of 10(4) cells of colon adenocarcinoma (DHD/K12/TRb) the influences of either taurolidine or taurolidine/heparin on intraperitoneal and subcutaneous tumour growth were investigated in 105 rats undergoing laparoscopy with carbon dioxide. The animals were then randomised into seven groups. A pneumoperitoneum was established using carbon dioxide for 30 min (8 mmHg). Three incisions were used: median for the insufflation needle, and a right and left approach in the lower abdomen for trocars. To investigate the intraperitoneal (local) influence of either taurolidine and heparin on tumour growth the substances were instilled intraperitoneally. Systemic effects were expected when the substances were applied intravenously (iv). Synergistic influences were tested when both application forms were combined. The number and the weight of tumours as well as the incidence of abdominal wall and port-site metastases were determined four weeks after intervention. Blood was taken to evaluate the influences of taurolidine and heparin on systemic immunologic reactions: seven days before laparoscopy. two hours, two days. seven days, and four weeks after operation, and the peripheral lymphocytes were determined.

RESULTS

Intraperitoneal (ip) tumour weight in rats receiving taurolidine (median 7 mg) and taurolidine/heparin (0 mg) intraperitoneally was significantly reduced when compared to the control group (52 mg) (P = 0.001). There was no difference of subcutaneus tumour growth among the groups (P = 0.4). Trocar recurrences were decreased when taurolidine was applied ip (3115). ipiv (4/15), and ip in combination with heparin (4/15) in comparison to the control group (10/15). Immediately after intervention treated and untreated groups showed a peripheral lymphopenia.

CONCLUSIONS

The intraperitoneal therapy with taurolidine and the combination with heparin inhibits the intraperitoneal tumour growth and trocar recurrences. Neither the intraperitoneal nor the systemic application or the combination of taurolidine and heparin did reduce the subcutaneous tumour growth. The intervention caused a lymphopenia which was compensated on day two.

Taurolidine improves survival by abrogating the accelerated development and proliferation of solid tumors and development of organ metastases from circulating tumor cells released following surgery

BACKGROUND

Surgical trauma is partly responsible for enhancing tumor growth through a variety of mechanisms that are still not fully elucidated. The use of perioperative immunostimulants may modulate these effects. This study examined the effect of administration of taurolidine after laparotomy or laparoscopy on the growth of solid tumor, the establishment of hepatic and lung metastases, and effects on natural killer (NK) and lymphokine-activated killer (LAK) cell function.

METHODS

B16 melanoma right flank tumors were established in mice (n = 180). These animals underwent anesthesia only (control) or laparotomy or laparoscopy (n = 60 per group) and were randomized to receive either saline or taurolidine (n = 30 per group) at specific time points. Survival was determined in each group, and in a further 90 mice tumor growth was followed over 10 days postoperatively. The experiment was repeated in 540 mice, which underwent one of the three procedures and were treated with either saline or taurolidine. NK and LAK cell cytotoxicity (NKCC, LAKCC) was determined at several time points postoperatively. In a further experiment, B16 melanoma tumor cells were delivered via tail vein injection (n = 180) and intrasplenic injection (n = 180). The effect of saline or taurolidine administration on survival after the establishment of metastases was determined, and again in a further 180 mice the establishment of metastatic deposits in the liver or lungs was determined after 8 days.

RESULTS

Survival appeared to be significantly decreased in both the solid-tumor model and the metastatic models undergoing laparotomy compared to laparoscopy and controls (P < 0.0001) and to a lesser extent in the laparoscopy group compared to controls (P < 0.001). Flank tumor growth and metastatic tumor formation were more significant in laparotomy groups compared to laparoscopy groups and controls, but also to a lesser extent in laparoscopy groups compared to controls (P </= 0.05). NKCC and LAKCC were significantly decreased in the same patterns (P < or = 0.03). However, treatment with taurolidine abolished these effects, restoring NKCC and LAKCC (P < or = 0.04) and laparoscopy groups (P < or = 0.001).

CONCLUSION

It appears that changes that occur after the trauma of laparotomy, and to a lesser extent, after laparoscopy, significantly enhance the growth of primary tumors as well as the development of metastases from circulating tumor cells and are associated with a suppression of host antitumor surveillance mechanisms. This not only affected tumor progression in the immediate postoperative period, but also ultimately affected survival. Taurolidine, a known immunostimulant, appears to abrogate the effects of surgical trauma on primary and metastatic tumor growth and also enhances survival. This may have significant value in the management of tumor-bearing patients undergoing resection.

A proteinase inhibitor decreases tumor growth in a laparoscopic rat model

BACKGROUND

The balance between proteolysis and protease inhibition in the formation and breakdown processes of the extracellular matrix plays a major role in tumor cell invasion. An understanding of this relationship gave rise to the therapeutic concept of lowering tumor cell invasion by inhibiting protease activity. Phosphoramidon is an unspecific proteinase inhibitor. This experimental study investigated the effect of intraperitoneal phosphoramidon administration on tumor growth in a laparoscopic rat model.

METHODS

In the first phase of the study, we investigated the influence of phosphoramidon on tumor cell invasion in a collagen matrix gel chamber in vitro. In a second experiment, a suspension of colon carcinoma cells (CC531) was introduced into the peritoneal cavity of male WAG rats. Prior to laparoscopy (at 6 mmHg for 20 min), the animals were randomized to two groups. At the start of laparoscopy, the test substance was applied intraperitoneally (group 1: controls, 1 ml 0.9% NaCl; group 2: 250 mg phosphoramidon in 1 ml 0.9% NaCl). Three weeks after the injection of tumor cells, the animals were autopsied and the tumor mass determined.

RESULTS

In comparison with the control group (tumor weight 7.42 +/- 1.01 g), intraperitoneal tumor growth in the experimental group was significantly (p < 0.001) reduced by the application of phosphoramidon (tumor weight, 3.22 +/- 1.06 g). Phosphoramidon also significantly (p < 0.05) reduced tumor cell invasion through the matrix gel.

CONCLUSION

The proteinase inhibitor phosphoramidon reduced tumor cell invasion in vitro and tumor cell growth in vivo in this laparoscopic rat model.

Guidelines 2000 for colon and rectal cancer surgery

BACKGROUND

Oncologic resection techniques affect outcome for colon cancer and rectal cancer, but standardized guidelines have not been adopted. The National Cancer Institute sponsored a panel of experts to systematically review current literature and to draft guidelines that provide uniform definitions, principles, and practices.

METHODS

Methods were similar to those described by the American Society of Clinical Oncology in developing practice guidelines. Experts representing oncology and surgery met to review current literature on oncologic resection techniques for level of evidence (I-V, where I is the best evidence and V is the least compelling) and grade of recommendation (A-D, where A is based on the best evidence and D is based on the weakest evidence). Initial guidelines were drafted, reviewed, and accepted by consensus.

RESULTS

For the following seven factors, the level of evidence was II, III, or IV, and the findings were generally consistent (grade B): anatomic definition of colon versus rectum, tumor-node-metastasis staging, radial margins, adjuvant R0 stage, inadvertent rectal perforation, distal and proximal rectal margins, and en bloc resection of adherent tumors. For another seven factors, the level of evidence was II, III, or IV, but findings were inconsistent (grade C): laparoscopic colectomy; colon lymphadenectomy; level of proximal vessel ligation, mesorectal excision, and extended lateral pelvic lymph node dissection (all three for rectal cancer); no-touch technique; and bowel washout. For the other four factors, there was little or no systematic empirical evidence (grade D): abdominal exploration, oophorectomy, extent of colon resection, and total length of rectum resected.

CONCLUSIONS

The panel reports surgical guidelines and definitions based on the best available evidence. The availability of more standardized information in the future should allow for more grade A recommendations.

Efficacy of surgical measures in preventing port-site recurrences in a porcine model

BACKGROUND

Port-site recurrences are serious complications of laparoscopy performed for cancer. Incidences reported in the literature vary between 0% and 21%, suggesting an influence of the surgeon.

METHODS

The aim of this experimental, prospective, randomized, single-blind study was to investigate the influence that the quality surgery has on the incidence of port-site recurrences. After a 12-mmHg carbon dioxide (CO2) pneumoperitoneum was created, 10(7) human HeLa cell were injected into the peritoneal cavity of 18 pigs, creating a xenogeneic tumor. Laparoscopic sigmoid resections then were performed using four trocars and a transanal double-stapling technique. The following protective measures were applied in nine animals: trocar fixation, prevention of gas leaks, rinsing of instruments with povidone-iodine, minilaparotomy protection, rinsing of trocars before removal, peritoneal closure, and rinsing of all wounds with povidoneiodine. Surgeons and type of procedures were randomized. After 4 weeks, the animals were killed and all portsites excised. Blinded immunohistologic analysis with antihuman pancytokeratin antibody was performed.

RESULTS

Tumor recurrence was present in 23 of 36 port sites (63.8%) in the control group, but only in 5 of 36 port sites (13.8%) in the group that received protective measures (p = 0.002; Fisher's exact test). No peritoneal carcinosis nor anastomotic recurrences were observed.

CONCLUSION

These results strongly suggest that the quality of surgical technique has an influence on the incidence of port-site recurrences. From now on, we propose to use these protective measures routinely in cancer laparoscopy.

Taurolidine inhibits tumor cell growth in vitro and in vivo

BACKGROUND

Taurolidine, a derivative of the amino acid taurine, exhibits antiendotoxin, antibacterial, and antiadherence activity. We hypothesized that Taurolidine may inhibit tumor cell growth, both in an in vitro and in vivo setting. Our aim was to examine the effect of Taurolidine on the growth of a rat metastatic colorectal tumor cell line (DHD/K12/TRb) in vitro and in vivo.

METHODS

In the in vitro experiments, DHD/K12/TRb cells were incubated with 5, 10, 15, 25, microg/ml of Taurolidine. Cells incubated in culture medium alone were used as controls. Cell proliferation, cell viability, cell death, and cell apoptosis were measured using commercially available techniques. In the in vivo experiment, BD IX rats were randomized into two groups (n = 10/group). Group A (control) underwent laparotomy and instillation of DHD/K12/TRb tumor cells intraperitoneally followed by phosphate buffered saline (PBS). Group B received Taurolidine (100 mg/kg) instead of PBS. Animals were killed after 24 days and tumor burden assessed by counting the number of tumor nodules in the peritoneal cavity.

RESULTS

Incubation of the tumor cells with Taurolidine resulted in a 4-fold decrease in proliferation rates (25+/-4% vs. 100+/-28% for controls) and a 4-fold increase in cell necrosis as demonstrated by the increase in LDH release (403+/-28% vs. 100+/-26% for controls), at a Taurolidine concentration of 25 microg/ml. A dose-dependent decrease in cell viability was also observed. In the in vivo study, local Taurolidine administration resulted in significant decreases in tumor burden (3+/-1 nodules in Group B animals vs. 649+/-101 nodules in Group A animals).

CONCLUSIONS

Taurolidine inhibits the growth of a rat metastatic colorectal tumor cell line in vitro and in vivo and thus may have potential in the prevention of peritoneal metastases.

Cancer and laparoscopy, experimental studies: a review

OBJECTIVE

To review the experimental studies on laparoscopy and cancer and to propose guidelines for the clinical management of gynecologic cancer.

METHODS

The literature in MEDLINE was searched from January 1992 to December 1998 using the terms 'cancer', 'laparoscopy' and 'experimental or animal study'. Cross-referencing identified additional publications. Abstracts and letters to the editor were excluded. All the relevant papers were reviewed.

RESULTS

Depending on the model used, controversial results have been reported on the incidence of trocar site metastasis when comparing CO(2) laparoscopy and laparotomy. In contrast, the following conclusions can be proposed: (i) tumour growth after laparotomy is greater than after endoscopy; (ii) tumour dissemination is worse after CO(2) laparoscopy than after laparotomy; (iii) some of the disadvantages of CO(2) laparoscopy may be treated using local or intravenous treatments or avoided using other endoscopic exposure methods, such as gasless laparoscopy.

CONCLUSIONS

The laparoscopic treatment of gynecologic cancer has potential advantages and disadvantages, and may only be performed in prospective clinical trials. The risk of dissemination appears high when a large number of malignant cells are present. Adnexal tumours with external vegetations, and bulky lymph nodes should be considered as contra-indications to CO(2) laparoscopy.

Description of an intraperitoneal tumour xenograft survival model in the pig

AIMS

Experimental animal studies are necessary if the results of minimally invasive oncological surgery are to be improved. In particular the influence of surgical technique on tumour implantation needs further assessment. Small animals such as rodents are inappropriate for such laparoscopic surgical studies. There is a requirement for another animal tumour model with animals greater in size.

METHODS

Accordingly we developed an intraperitoneal tumour xenograft survival model using the domesticated pig. After creating a 12 mmHg pneumoperitoneum, 10(7)human HeLa cells were injected into the peritoneal cavity of nine non-syngeneic animals to induce tumour xenograft. Resection of the sigmoid colon using four trocars and a transanal double-stapling technique was performed. The mean operating time was 69 min. No signs of post-operative pain symptoms were observed, and all the animals survived the procedure and gained weight. After 4 weeks, the animals were sacrified and all incision sites and anastomoses were excised.

RESULTS

Immunohistochemical staining with antihuman pancytokeratin antibodies confirmed tumour implants in 25 out of 36 port-sites (63.8%). No peritoneal carcinosis nor tumour implants at anastomosis sites were observed.

CONCLUSION

This intraperitoneal xenograft tumour model in the pig can be applied in survival studies to check the quality of surgical techniques and its influence on tumour implantation following laparoscopy for cancer.

Feasibility of therapeutic pneumoperitoneum in a large animal model using a microvaporisator

BACKGROUND

Multimodal therapy is used increasingly in advanced gastrointestinal tumors. Potential benefits of using an intraoperative adjuvant therapy during laparoscopy for cancer have been documented in animal studies. The aim of this study was to develop a device that could deliver such an intraoperative drug therapy.

METHODS

We developed a micropump suitable for minimally invasive surgery procedures that allowed microdroplets of therapeutic substance to be distributed into the pneumoperitoneum (CO2), creating a "therapeutic pneumoperitoneum." A closed-loop control system regulates drug delivery according to the gas flow. In vitro, the micropump is able to aerosolize various aqueous and ethanol solutions, including cytostatic and bacteriostatic drugs and adhesion-modulating agents. The size of the microdroplets has been optimized to prevent visual artifacts.

RESULTS

The micropump was tested in an animal model (pig). The system was inserted into a 5-mm trocar. After insufflation of a 12-mm CO2 pneumoperitoneum, laparoscopic sigmoid colon resections could be performed with no special difficulties. No fog developed, and no system-related complication was observed. At autopsy, the active principle was distributed to all exposed peritoneal surfaces.

CONCLUSIONS

As opposed to conventional peritoneal washing, therapeutic pneumoperitoneum reaches the entire peritoneal surface, allowing an optimal drug distribution. Drug diffusion into the tissues is enhanced by the intraperitoneal pressure. Precise determination of the instantaneous and total drug quantity is possible. Therefore, this drug delivery system has several advantages over conventional irrigation. Its potential domains of application are locoregional cancer therapy, prevention of port-site recurrences, immunomodulation, analgesia, peritonitis, and prevention of postoperative adhesions.

Experimental study of the effect of intraperitoneal heparin on tumour implantation following laparoscopy

BACKGROUND

Conclusions drawn from clinical reports of port site metastases following laparoscopic resection of intra-abdominal malignancy are now supported by a burgeoning experimental literature which suggests that laparoscopy promotes tumour metastasis to wounds. This study investigated the effect of intraperitoneal blood and heparin on the incidence of tumour cell implantation and port site metastasis.

METHODS

Twenty-four Dark Agouti rats underwent laparoscopy with carbon dioxide insufflation and the instillation of a tumour cell suspension and/or blood into the peritoneal cavity. Rats were allocated randomly to one of the following study groups (six rats per group): (1) controls; (2) intraperitoneal blood (2 ml blood introduced from a syngeneic donor rat); (3) intraperitoneal heparin; (4) intraperitoneal blood and heparin. Rats were killed 7 days after the procedure, and the peritoneal cavity and port sites were examined for the presence of tumour.

RESULTS

Tumour implantation and port site metastases were reduced by the intraperitoneal administration of heparin, but increased by the presence of intraperitoneal blood.

CONCLUSION

The results of this study suggest that tumour implantation following laparoscopy is promoted by the presence of intraperitoneal blood and that this effect may be reduced by the use of intraperitoneal heparin.

Incidence of port site recurrence after laparoscopic cholecystectomy for preoperatively unsuspected gallbladder carcinoma

BACKGROUND

We sought to determine the incidence of recurrence of carcinoma at the port site and the outcome of patients with such recurrences after exploratory laparoscopy/laparoscopic cholecystectomy for unsuspected gallbladder carcinoma and analyzed aspects of the laparoscopic procedure associated with recurrences at the port site.

METHODS

Thirty-seven patients with preoperatively unknown adenocarcinoma of the gallbladder were analyzed. The patients were part of a large prospective study of the Swiss Association of Laparoscopic and Thoracoscopic Surgery including 10,925 patients undergoing laparoscopic cholecystectomy.

RESULTS

Preoperatively undiagnosed adenocarcinoma of the gallbladder is rarely encountered in patients undergoing laparoscopic cholecystectomy (0.34%). The incidence of recurrence of carcinoma at the port site in these patients is 14% (5 of 37) and is similar whether the primary tumor is confined to the gallbladder (T1/T2) or locally advanced (T3/T4). The recurrences at the port site were diagnosed within 6 to 16 months (median 10 months) after the operation. Patients with an intraoperative perforation of the gallbladder had a higher incidence of recurrences at the port site (40%) than had patients without perforation (9%; P = .13). All patients with recurrences at the port site had distant metastases and all died of the disease 12 to 35 months (median 19 months) after cholecystectomy; all patients with such recurrences and stage T1/T2 tumors subsequently had peritoneal metastases.

CONCLUSIONS

Patients with a preoperatively undiagnosed adenocarcinoma of the gallbladder undergoing laparoscopy or laparoscopic cholecystectomy have a high incidence of recurrences at the port site, and the incidence increases when a gallbladder perforation occurs during the operation. All patients with such recurrences died of the disease. The diagnosis of an isolated recurrence at the port site may therefore be an indicator of disseminated disease in most cases.