The influence of laparotomy and laparoscopy on tumor growth in a rat model

Early cervical cancer managed by laparoscopy and conventional surgery: comparison of treatment results

INTRODUCTION

The goal of this retrospective analysis was to compare the results of treatment in patients with early cervical cancer managed by laparoscopy with those for patients observed after laparotomy.

METHODS

The retrospective analysis was carried out with 22 patients operated on with total laparoscopic hysterectomy and 58 patients treated by abdominal hysterectomy. Patients with clinical tumor stage IA, IB1, or IIA were eligible for surgery. The main efficacy end point was disease-free survival evaluated by the Kaplan-Meier method. The survival curves were compared using log-rank tests. In addition, length of hospitalization, duration of surgery, and complication rate were compared. P < 0.05 was set as statistically significant.

RESULTS

Predicted 3-year disease-free survival rates in the "open surgery" and "laparoscopy" groups were 0.86 (standard deviation [SD], 0.049) and 0.82 (SD, 0.098), respectively (P = 0.53). Recurrence rate was 13.6% after laparoscopy and 12% in open surgery. In 2 patients, intraperitoneal spread occurred after laparoscopy. The operation time was longer and hospitalization shorter after laparoscopy.

CONCLUSIONS

The 3-year disease-free survival was similar in both groups. Total laparoscopic radical hysterectomy may be an option in early cervical cancer; however, the intraperitoneal spread in 2 patients compels a search for possible risk factors in patients managed by laparoscopy.

Consequences of surgical stress on the kinetics of skin wound healing: partial hepatectomy delays and functionally alters dermal repair

The objective was to determine the significance of surgical trauma in dermal wound healing. Using intravital microscopy, we analyzed the healing kinetics of full-thickness dermal wounds in the ears of SKH1 mice. Partial hepatectomy (pHx) simulated major surgical trauma, while laparotomy only served as a sham operation (sham). Animals without abdominal surgery served as controls (control). Laparotomy wounds were analyzed for biomechanical qualities and collagen deposition. Morphological characterization of skin repair was performed by histology/immunohistochemistry. In vitro cell assays assessed the paracrine effects of surgical stress. PHx caused a transient increase in tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 levels and led to weight loss, reflecting the host's overall response to surgery. Wound closure in pHx animals was delayed vs. control and sham animals, as indicated by significantly lower values of epithelialization and neovascularization over 10 days. Ear wound histology further revealed a provisional wound matrix with a reduced microvessel density. Moreover, pHx-laparotomy wounds showed a reduced bursting strength coexisting with significantly decreased collagen content. PHx and sham serum caused a significant alteration in in vitro fibroblast viability. Skin healing is dependent on the extent of surgery and is influenced by its paracrine effects. Therefore, considerable effort should be focused on the development of strategies limiting surgery-associated perturbations of dermal repair.

Laparoscopic pancreatic resection for cancer

Laparoscopic (lap) organ resection is now commonly performed for the management of solid tumors of the kidney, colon, adrenal glands and prostate. Surgeons have been slower to adopt minimally invasive approaches to the pancreas owing to operative complexity and complication potential. The majority of existing reports concerning lap pancreatectomy are single-center studies that describe experience with fewer than 20 cases. Only recently have larger experiences surfaced demonstrating the safety and efficacy of lap tumor enucleation and lap left pancreatectomy. As neoplastic disease is the most common indication for pancreatic resection, understanding the effects of the lap approach to pancreatectomy on cancer outcome is crucial. In addition to concerns of port-site tumor recurrence and tumor dissemination due to lap manipulation in the setting of pneumoperitoneum, adequacy of resection as defined by margin status and nodal assessment must be considered. This review covers the development and current state-of-the-art of lap pancreatic surgery for cancer. Existing data are reviewed for both open and lap pancreatic resections, with particular attention to pancreatic ductal adenocarcinoma. Projections of future advances in the field of lap pancreatic surgery are provided.

An acidic extracellular pH induces Src kinase-dependent loss of beta-catenin from the adherens junction

Little attention has been paid to the role of adherens junctions (AJs) in acidic extracellular pH (pHe)-induced cell invasion. Incubation of HepG2 cells in acidic medium (pH 6.6) induced cell dispersion from tight cell clusters, and this change was accompanied by downregulation of beta-catenin at cell junctions and a rapid activation of c-Src. Pretreatment with PP2 prevented the acidic pH-induced downregulation of beta-catenin at AJ and in the membrane fractions. The acidic pHe-induced c-Src activation increased tyrosine phosphorylation of beta-catenin and decreased the amount of beta-catenin-associated E-cadherin. The depletion of membrane-bound beta-catenin coincided with enhanced cell migration and invasion, and this acidic pHe-increased cell migration and invasion was prevented by PP2. In conclusion, this study characterizes a novel signaling pathway responsible for acidic microenvironment-promoted migration and invasive behaviors of cancer cells.

Laparoscopic surgery induced interleukin-6 levels in serum and gut mucosa: implications of peritoneum integrity and gas factors

BACKGROUND

The peritoneum serves as an integral part of host immunity, and the homeostasis of intraperitoneal environment is held to be beneficial for patient recovery after abdominal surgery. How minimal invasive access to the abdomen by laparoscopy and incisions would alter the intraperitoneal immune response is not fully defined. This study examined the levels of IL-6 in serum and gut mucosa following laparoscopic surgery with reference to the peritoneum integrity and gas factors.

METHODS

BALB/c mice were divided into three groups (ten animals in each group) that underwent different abdominal surgical treatments: laparotomy (open group), laparoscopy with atmospheric air (air group) or carbon dioxide pneumoperitoneum (CO(2) group). A 3-cm incision of the skin and muscle was made in all animals except the peritoneum was left intact in the latter two animal groups in order to cancel out the incisional tissue injury present in laparotomy. Four hours after surgery, serum, and jejunal mucosa were extracted for IL-6 measurement by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Open laparotomy resulted in significant elevation of serum IL-6 level when compared to the laparoscopic procedures in the descending order of open > air > CO(2) groups. For the mucosal IL-6 level, both the open and air groups were significantly higher than the CO(2) group. Data from multivariate analysis revealed that breaching or incision of the peritoneum was an important factor for the elevated levels of IL-6 in serum (p < 0.001) and jejunal mucosa (p = 0.032).

CONCLUSION

The present study suggests that laparoscopic techniques to minimize the size of the peritoneal incision as well as exposure to atmospheric air can potentially reduce postoperative stress responses associated with abdominal surgery and prompt early recovery.

Laparoscopy and Malignancy

BACKGROUND

The advantages of pneumoperitoneum-based surgery are well documented. Laparoscopy is the gold standard of treatment in certain benign conditions such as cholelithiasis and gastroesophageal disease. This success has led to the application of laparoscopy in the management algorithm of malignant conditions. There is currently no universally accepted consensus of the role of pneumoperitoneum-based surgery in the treatment of cancer. This is due to the early reports of port site metastasis, initial lack of randomized controlled trials and the concern of performing oncologically adequate operations. The aim of this section is to review the current literature and attempt to obtain a consensus of the role of laparoscopy in the treatment of cancer.

MATERIALS AND METHODS

A literature search was conducted through Pubmed with key words laparoscopy, pneumoperitoneum, carbon dioxide, malignancy, cancer, and port site metastasis. The obtained results were divided into various sections such as non-randomized reports, randomized reports, animal studies, human studies, etc. A comparison was made between laparoscopic and open resections when possible.

RESULTS

There are several published reports of studies in animal models and in humans relating to pneumoperitoneum-based surgery in the setting of malignancy. There are also a few randomized controlled trials that compared open versus laparoscopic surgery for malignancies of various organ systems. In addition, the early reports of alarmingly high rate of port site metastasis have been scaled down to rates comparable to wound recurrences after open resections.

SUMMARY

Laparoscopy has added another dimension to the management of patients with cancer. Advanced training, superior instrumentation, and a better understanding of the pathophysiology of carbon dioxide pneumoperitoneum has led to the successful application of laparoscopy. The improved results are obtained in centers with high volume of patients and with experience in both fields of oncology and minimally invasive surgery. Laparoscopy is now an integral tool in the management algorithm of malignancies of some organ systems and its role will be further expanded in the future.

Surgery promotes implantation of disseminated tumor cells, but does not increase growth of tumor cell clusters

INTRODUCTION

Local recurrence and peritoneal dissemination is common after intentionally curative resection of colorectal carcinoma. It is not yet clear which mechanisms stimulate post-operative intra-abdominal tumor development. Enhanced adhesion or growth of tumor cells and/or post-operative immuno suppression may influence tumor recurrence.

AIMS OF THE STUDY

In the present study, we evaluated effects of local and remote surgery on intra-abdominal tumor development.

MATERIALS AND METHODS

A standardized intra-abdominal trauma was inflicted by rubbing both uterus horns in laparotomy groups, while a dorsolateral thoracotomy was performed in thoracotomy groups (on day -1, 0, or +3). To induce tumor development rats were injected intra-peritoneally with the coloncarcinoma cell line CC531s on day 0 and evaluated after 21 days.

RESULTS

Rats undergoing laparotomy and injection on day 0 showed significantly higher tumorload than control rats (195 +/- 20 vs. 47 +/- 29, P < 0.001). When a laparotomy was performed, the day before tumor inoculation even higher tumorload was seen (245 +/- 37 vs. 195 +/- 20, P < 0.01). Strikingly, performing a thoracotomy on the day before or on the same day as tumor inoculation resulted in enhanced tumorload compared to controls as well (135 +/- 84 vs. 47 +/- 29; P < 0.001 and 88 +/- 38 vs. 47 +/- 29; P < 0.02, respectively). Either laparotomy or thoracotomy 3 days after tumor cell inoculation did not affect growth of pre-existing tumor cell clusters.

CONCLUSIONS

The (post) surgical intra-peritoneal microenvironment enhances successful implantation of spilled tumor cells, whereas growth of adhered tumor cell clusters is not affected. The inflammatory response as a result of remote surgery promotes successful tumor development as well.

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 enhancement of tumour cell binding to the peritoneum is inhibited by anti-intercellular adhesion molecule-1 monoclonal antibody

BACKGROUND

There still remain some concerns over the phenomenon of port-site metastases (PSM) after laparoscopic surgery. The aim of this study was to investigate the effect of the pneumoperitoneum on tumor-mesothelial cell interactions.

METHODS

The adhesion of a colon carcinoma cell line to a mesothelial cell monolayer exposed to carbon dioxide, helium, or air was assessed using an in vitro adhesion assay. Changes in adherence were correlated with alterations in cell surface molecule expression by the mesothelial cells using flow cytometry after exposure to the different environments.

RESULTS

Exposure of the mesothelial cells to an in vitro pneumoperitoneum significantly enhanced tumor cell binding to the mesothelial cell monolayer. No differences in cell viability were observed between the groups. This was associated with increased expression of mesothelial intercellular adhesion molecule-1 (ICAM-1) mediated by nuclear factor kappa-B. The enhanced adhesion was abolished by ICAM-1 inhibition.

CONCLUSIONS

This study demonstrated that the laparoscopic environment increases the susceptibility of the mesothelium to tumor cell adherence, and this may be explained by changes in ICAM-1 expression.

Local and systemic chemotherapy with taurolidine and taurolidine/heparin in colon cancer-bearing rats undergoing laparotomy

Experimental studies in the therapy of malignant abdominal tumors have shown that different cytotoxic agents suppress the intraperitoneal tumor growth. Nevertheless, a general accepted approach to prevent tumor recurrences does not exist. Following subcutaneous and intraperitoneal injection of 10(4) colon adenocarcinoma cells (DHD/K12/TRb), the influences of both taurolidine or taurolidine/heparin on intraperitoneal and subcutaneous tumor growth was investigated in 105 rats undergoing midline laparotomy. The animals were randomized into 7 groups and operated on during 30 min. To investigate the intraperitoneal (local) influence of either taurolidine or heparin on tumor growth, the substances were applied intraperitoneally. Systemic and intraperitoneal effects were evaluated after intravenous injection of the substances. Both application forms were also combined to analyze synergistic effects. Tumor weights, as well as the incidence of abdominal wound metastases, were determined four weeks after the intervention. In order to evaluate the effects of the agents, blood was taken to determine the peripheral leukocytes counts. Intraperitoneal tumor growth in rats receiving intraperitoneal application of taurolidine (median 7.0 mg, P = 0.05) and of taurolidine/heparin (median 0 mg, P = 0.02) was significantly reduced when compared to the control group (median 185 mg). The simultaneous instillation of both agents also reduced the intraperitoneal tumor growth (median 4 mg, P = 0.04), while the intravenous injection of the substances caused no local effect. In contrast, the subcutaneous tumor growth did not differ among all groups. In all groups, abdominal wound recurrences were rare and did not differ. Independent of the agents and the application form, the operation itself caused a slight leukopenia shortly after the operation and a leukocytosis in the following course. Intraperitoneal therapy of either taurolidine or in combination with heparin inhibits local tumor growth and abdominal wound recurrences in rats undergoing midline laparotomy. Neither the intraperitoneal nor the intravenous application or the combination of the two agents influenced the subcutaneous tumor growth. The substances did not alter the changes of peripheral leukocytes.

Effect of carbon dioxide on human ovarian carcinoma cell growth

OBJECTIVE

Laparoscopy may be associated with increased risk of ovarian carcinoma wound metastases. This study was designed to determine whether carbon dioxide exposure increases the growth of human ovarian cancer cells in vitro.

STUDY DESIGN

Immortalized ovarian epithelial carcinoma cell (SKOV-3 cell line) cultures were exposed to carbon dioxide, nitrous oxide, or culture media with decreased pH for up to 3 hours. Cell growth was determined with the use of a spectrophotometric assay, and the results were compared with control cells by paired t tests and linear regressions analysis.

RESULTS

Carbon dioxide exposure increased SKOV-3 cell growth by 52% after 4 days in culture. The increased cell growth had a linear relationship to the length of carbon dioxide exposure. Cells that were exposed to either nitrous oxide or media with pH 6.3 showed a trend toward decreased growth.

CONCLUSION

Carbon dioxide exposure increases the in vitro growth of human ovarian carcinoma cells by an effect that is independent of the carbon dioxide-related decrease in the culture media pH.

Morphology of the murine peritoneum after pneumoperitoneum vs laparotomy

BACKGROUND

Although there have been studies of the effects of pneumoperitoneum on the peritoneal cavity, we still do not know whether the morphologic changes to the peritoneum are different for pneumoperitoneum vs laparotomy. Using scanning electron microscopy, we examined the murine peritoneum after pneumoperitoneum vs laparotomy and compared the changes.

METHODS

Forty-five mice were anesthetized with diethyl ether and divided into seven groups. Pneumoperitoneum was established at 5 mmHg for 30 min with carbon dioxide (CO(2)) (n = 9), helium (n = 9), and air (n = 9). One group underwent laparotomy for 30 min (n = 9), and a control group underwent anesthesia only (n = 3). CO(2) pneumoperitoneum was further established at 10 mmHg for 30 min (n = 3) and at 5 mmHg for 60 min (n = 3). After the procedures, the peritoneum was resected from the mesenterium of the small intestine in each animal and examined by scanning electron microscope for morphologic changes of the mesothelial cells.

RESULTS

Bulging up of the mesothelial cells was evident immediately after pneumoperitoneum, whereas detachment of the mesothelial cells was present immediately after laparotomy. Bulging up of the mesothelial cells was reduced at 24 h after CO(2) pneumoperitoneum and fully resolved at 72 h in all pneumoperitoneum groups, whereas the mesothelial cells remained detached at 72 h in the laparotomy group. Intercellular clefts were found immediately after helium pneumoperitoneum and were present at 24 h and 72 h after helium pneumoperitoneum, but they were not seen after air pneumoperitoneum and were only evident after CO(2) pneumoperitoneum at 10 mmHg. Depression of the mesothelial cell surface was observed when pneumoperitoneum lasted 60 min.

CONCLUSION

Morphologic peritoneal alterations after pneumoperitoneum differed from those after laparotomy and were influenced by the type of gas, amount of pressure, and duration of insufflation. These peritoneal changes after pneumoperitoneum may be associated with a specific intraperitoneal tumor spread after laparoscopic cancer surgery.

Impact of pneumoperitoneum on visceral metastasis rate and survival. Results in two ovarian cancer models in rats

OBJECTIVE

To compare the impact of CO2 laparoscopy, gasless laparoscopy, and midline laparotomy on the development of distant metastases and on survival in two ovarian carcinoma models.

DESIGN

A prospective randomised study in rats.

MATERIAL

and methods Two ovarian cancer xenografts were obtained by intraperitoneal injection of IGR-OV1 or NIH-OVCAR-3 cells. Experimental surgical procedures were performed on day 7 (IGR-OVI model) or day 14 (NIH: OVCAR-3 model) after intraperitoneal injection: CO2 laparoscopy (pneumoperitoneum (PNP) with unheated CO2 at a pressure of 8 mmHg for 1 hour); gasless laparoscopy (consisting in abdominal wall expansion by a balloon for 1 hour); midline laparoscopy (consisting in bowel exteriorisation on a mesh for one hour following xyphopubic laparotomy). The control group underwent general anaesthesia alone. The animals were killed by CO2 inhalation as soon as they became moribund.

MAIN OUTCOME MEASURES

Pathological examination was carried out on the liver, lungs and pleura as well as the retroperitoneal nodes. Survival was determined from the time of surgery to the sacrifice of the animal. Statistical analysis used ANOVA, Fisher exact test, Bonferonni method and the log-rank test.

RESULTS

In the IGR-OV1 model, distant metastases were rare, and were not promoted by CO2 laparoscopy. With the NIH: OVCAR-3 model, pleural, pulmonary and para-aortic metastases were not enhanced by CO2 PNP when compared with other approaches. Conversely, midline laparotomy and laparoscopy significantly increased liver involvement when compared with gasless laparoscopy (P = 0.04 and P = 0.008). Survival was comparable no matter what kind of surgery had been performed in the IGR-OV1 model (P = 0.7) or in the NIH: OVCAR-3 model (P = 0.5).

CONCLUSIONS

CO2 laparoscopy had a minor impact on distant and nodal metastases in the two models. Similarly, survival was similar for all surgical groups.

Results of retroperitoneal laparoscopic radical nephrectomy

PURPOSE

To analyze the retroperitoneal approach to laparoscopic radical nephrectomy in terms of feasibility, safety, morbidity, and cancer control.

PATIENTS AND METHODS

We reviewed the records of 50 consecutive patients with renal cancer underwent radical nephrectomy via the retroperitoneal laparoscopic approach from 1995 through 1999.

RESULTS

The mean operative time was 139 minutes (range 60-330 minutes) with a mean of 149.78-mL operative blood loss (0-1500 mL). The mean renal size was 100 mm (70-150 mm) with a mean tumor size of 38.6 mm (20-90 mm). The postoperative hospital was 6 days (2-13 days). Three open conversions were necessary: one for laparoscopically uncontrolled bleeding and two because obesity interfered with surgery. We noted two major complication and two minor complications. Two disease progression have been noted to date. One patient with a pT3 grade 2 renal-cell carcinoma had a local recurrence with liver metastasis 9 months after the procedure and died 19.7 months after radical nephrectomy. Another patient with a pT3aN+M+ cancer died 23.1 months after the procedure.

CONCLUSION

Retroperitoneal laparoscopic nephrectomy for kidney cancer requires further assessment. It seems to have several advantages over open radical nephrectomy and to be effective and safe for small (<50-mm) renal tumors.

Alterations in the immune system and tumor growth in laparoscopy

BACKGROUND

The explosion in the use of therapeutic laparoscopy during the past decade has focused much research interest on finding a basic scientific support for the clinically apparent attenuation of the stress response to surgery. In particular, the potential impact that attenuation of the immune response to surgery may have on laparoscopy for the cure of malignancy has attracted much attention.

METHODS

A review of the published literature on the stress response to laparoscopic surgery and the impact of laparoscopy on tumor growth was performed.

RESULTS

Evidence favors an attenuation of the immune response to surgery with laparoscopic cholecystectomy. Whether this is true also of more major procedures such as laparoscopically assisted colectomy for malignancy is currently unclear. In animal models, tumor growth after laparoscopic surgery is less than after laparotomy and depends on the insufflation agent used.

CONCLUSIONS

Laparoscopic cholecystectomy appears to be associated with attenuation of the immune response to surgery. The implications of these findings for the future use of laparoscopic surgical techniques for malignant disease remain unclear.

Laparotomy, laparoscopy, cancer, and beyond

The fate of laparoscopic methods for the treatment of cancer remains uncertain. Published middle-range oncologic results from nonrandomized studies demonstrate that laparoscopic methods are associated with an outcome comparable with results after open resection. The world awaits the 3- and 5-year oncologic results of the ongoing randomized and prospective trials. There is a possibility that laparoscopic methods may be associated with a survival benefit. Port tumors remain a concern. However, results at this writing suggest that these recurrences take place at a frequency similar to that of incisional recurrences following open cancer resection. Port tumors currently are viewed as local recurrences. Traumatization of the tumor at the time of resection is thought to be the most important surgery-related risk factor. The demonstration of a survival benefit in a randomized trial would likely have a tremendous impact on the surgical world. Avoidance of laparotomy-related immunosuppression and tumor stimulation, both of which have been well demonstrated in animal studies, theoretically, might account for differences in cancer outcome. The early postoperative period may be a critical time during which the fate of many cancer patients is determined. It is possible that this may be an ideal time frame for antitumor immunotherapy because the tumor burden is at its lowest, and because immunotherapy, unlike conventional chemotherapy, is unlikely to have a negative impact on wound and anastomotic healing. Perioperative nonspecific upregulation of immune function via pharmacologic means may improve long-term oncologic results. Similarly, preoperative tumor vaccines might provide patients with a specific means of combating any remaining tumor cells after curative resection. The results of several recently completed murine studies support both of these ideas. Finally, early postoperative administration of monoclonal antitumor antibodies might provide patients with specific means of combating any remaining tumor cells after curative resection. The introduction of advanced minimally invasive techniques nearly a decade ago has led to new methods of approaching malignant tumors that have the potential to have an impact on the oncologic outcome of cancer patients. This decade-long journey also has led to new insights regarding the impact of surgery on the patient. It also has alerted us concerning the importance of the immediate postoperative period in the patient's ongoing struggle against the tumor. These insights hopefully will lead to better surgical methods and new perioperative adjuvant therapies that will increase the rate of survival and reduce the recurrence rates for cancer patients.

Differences in tumour growth, tumour cell proliferation and immune function after laparoscopy and laparotomy in an animal model

BACKGROUND

Clinical and experimental studies have shown that laparoscopy preserves the immune response and can give better clinical results than laparotomy. However, the use of laparoscopy for the treatment of cancer patients is still controversial due to the risk of port-site and haematogenous metastases and increased tumour growth. The purpose of this experimental study was to assess tumour growth and the mechanism of differential tumour behaviour after laparoscopy and laparotomy.

METHODS

Seventy-five young, male Wistar rats were randomly assigned to one of two experiments. Experiment 1: 45 animals were inoculated subcutaneously with Walker carcinosarcoma 256 cells and were subdivided into three groups of 15 rats. Control group la was submitted to anaesthesia only, group 1b received carbon dioxide (CO(2)) pneumoperitoneum,while group 1c received a laparotomy. Animals were sacrificed on postoperative day (POD) 7; tumours were excised and weighed to evaluate tumour growth. Nucleolar organiser regions identified by silver staining (AgNORs) were analysed to evaluate cell proliferation. Experiment 2: 30 rats were submitted to the same procedures as before, with ten animals in each group (2a, 2b, 2c), and a delayed-type hypersensitivity response (DTH) was used to evaluate the immune function.

RESULTS

The average tumour mass was 1.76 g in group 1a, 2.81 g in group 1b and 4.21 g in group 1c (p < 0.05). The AgNOR expression results were similar in the three groups. The immune function was better preserved in the control group (2a: average inflammatory area on POD1 = 106 mm(2) and on POD2 = 128.18 mm(2)), than in the pneumoperitoneum group (2b: average inflammatory area on POD1 = 79.75 mm(2) and on POD2 = 126.93 mm(2)); the worst results were in the laparotomy group (2c: average inflammatory area on POD1 = 33.33 mm(2) and on POD2 = 61.32 mm(2)).There were significant differences between groups 2a and 2c and between 2b and 2c.

CONCLUSION

Laparotomy stimulates a greater tumour growth than CO(2) pneumoperitoneum, but there is no difference in tumour cell proliferation. The cellular immune function is better preserved in animals submitted to CO pneumoperitoneum than in the laparotomized animals. These results suggest a relationship between a weaker immune response and a greater tumour growth.

Intraperitoneal macrophages and tumor immunity: A review

The macrophage (Mphi) is considered the first line of defense in immune response to foreign invaders. Increasing evidence suggests that Mphi(s) also play an important role against neoplastic cells. Mphi(s) exposed to supraphysiologic concentrations of CO(2) are suppressed. As surgeons apply newer minimally invasive techniques to oncologic therapies, it is important to evaluate the impact of these techniques on host-tumor interactions. We review the current understanding of Mphi biology with specific attention on cytotoxicity in addition to tumor immunity. Although systemic immune function is better preserved after laparoscopy than laparotomy, peritoneal Mphi(s) show reduced function after CO(2) pneumoperitoneum than exposure to air. Mphi(s) have shown cytotoxicity to syngeneic cancer cells and may play an important role in tumor surveillance. The impairment in Mphi function after CO(2) exposure may have an effect on outcome after oncologic surgery. In our understanding, Mphi(s) help destroy neoplastic cells. As CO(2) impairs Mphi activity, laparoscopy may significantly alter the host-tumor interaction.

Wound healing and colon carcinogenesis. Enhancing effects of skin wounding on development of colon tumors induced by 1,2 Dimethylhydrazine in the rat

This study demonstrates the tumor promoting effect at a distant site of skin wounding, in a model of colon carcinogenesis induced by 1,2 dimethylhydrazine (DMH) in the rat. Six-week-old male Wistar rats were given subcutaneous injections of DMH, 20mg/kg, or saline, once a week, for eight weeks. One week after the last DMH injection the animals received a full thickness skin wound in their dorsal skin and the wound was left open to heal by second intention. Control and DMH-treated rats, with or without skin wounds were killed at the 12th week, just after healing of the skin wound was complete. The colons were removed and divided into proximal and distal parts. Each segment was rolled as "Swiss roll"and processed for histology. The incidence, distribution and morphology of the colon tumors was recorded. The total number of tumors in the colonic mucosa and the number of tumors per rat was significantly higher in the skin-wounding DMH- treated group than in the unwounded group. In the histopathological analysis of the colon the number of poorly differentiated mucin-secreting carcinomas was 6-fold in the skin-wounding DMH-treated group than in the unwounded group and the majority of tumors were located near to lymphoid aggregates. The present results suggest that wound healing enhances tumor development at a distant site, such as the colon, and this effect seems to be related to tumor histology.

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.

Influence of CO2 pneumoperitoneum during laparoscopic surgery on cancer cell growth

BACKGROUND

CO2 pneumoperitoneum provides a new surgical environment to treat malignant disease. The purpose of this study was to investigate the influence of CO2 pneumoperitoneum during laparoscopic surgery on cancer cell growth.

METHODS

WiDr human colon cancer cells were incubated for 3 h under the following two conditions: 100% CO2 at 10 mmHg, and 95% air/5% CO2 (control). Cell proliferation was assessed by the WST-1 assay and BrdU assay. Tumor growth was assessed by subcutaneous injection into 20 nude mice. Cellular damage was measured by lactate dehydrogenase (LDH) assay.

RESULTS

The number of WiDr cells under pneumoperitoneal conditions decreased in the first 24 h. However, no significant difference was observed in the proliferation rate and tumor growth of the viable cells. LDH release of the CO2 pneumoperitoneal group was higher than that of the controls.

CONCLUSIONS

Our data indicate that CO2 pneumoperitoneum does not promote cancer cell proliferation but instead has a toxic effect on cancer cells.

Endometrial cell dissemination at diagnostic hysteroscopy: a prospective randomized cross-over comparison of normal saline and carbon dioxide uterine distension

The incidence of pelvic spreading of endometrial cells at diagnostic hysteroscopy was studied comparing the two distension media carbon dioxide (CO(2)) and normal saline (N/Saline). Thirty patients requiring laparoscopy and hysteroscopy were included in this study, the main indication for surgery being subfertility. Hysteroscopy was performed using both CO(2) and N/Saline distension on each patient, the order of the distension media being randomly allocated. Samples of peritoneal fluid were aspirated from the pouch of Douglas before and after hysteroscopy with each distension medium, and the specimens were investigated cytologically for the presence of endometrial cells. Endometrium was present in 2/30 (6.7%) peritoneal aspirates before and in 15/60 (25%) collected after the hysteroscopies. There was no major difference between liquid or gaseous distension, transtubal reflux of endometrial cells occurring in 7/30 (23.3%) and in 8/30 (26.7%) hysteroscopies respectively. Positive peritoneal cytology was observed significantly more often in patients who were in the proliferative phase of the menstrual cycle [9/14 (64.3%) versus 0/11, P < 0.004]. In conclusion, transtubal dissemination of endometrium occurs in about one quarter of patients, irrespective whether N/Saline or CO(2) is used for uterine distension; there is no advantage to using gaseous distension for hysteroscopy when investigating high-risk cases for endometrial malignancy.

The virtues and pitfalls of minimally invasive surgery for gynecological malignancies: an update

Operative laparoscopy is still jockeying for its place in the surgical management of gynecological malignancies. Its usefulness in staging these malignancies continues to be investigated, as does its ability to convert abdominal procedures to vaginal procedures. Recent articles also address the role of operative laparoscopy in less common procedures, as well as the curiosity of investigators to gain a better understanding of the 'consequences' of operative laparoscopy by using animal models. The reader is updated by a review of the reports published over the past year and a half.

[Laparoscopic resection of the colon for adenocarcinoma. Report of a series of 218 cases]

STUDY AIM

The aim of this retrospective study was to report the results of a series of 218 laparoscopic resections for adenocarcinoma of the colon by the same surgical team over a 6-year period.

PATIENTS AND METHODS

Laparoscopic procedures included, for the right and the left colon, at first a ligature of the vascular pedicles, secondarily a dissection of the mesocolons, and were almost identical to the conventional procedures. A conversion to open laparotomy was necessary in 8.3% of the patients. Among 218 patients, there were 117 men and 101 women; the mean age was 69 years. Twenty nine per cent of the patients had already undergone open laparotomy. Mean ASA grade was 2.1. An emergency operation was necessary for 9% of the patients in relation with colonic obstruction (n = 20) or peritonitis (n = 3).

RESULTS

Colonic resections were considered curative in 180 patients (82.6%). The mean duration of surgery was 157 minutes for the right colectomies and 148 for the left. The proportion of A, B, C, D Dukes stage tumours was respectively 19.3%, 38.5%, 27.5% and 14.7%. There was one post-operative death related to a serious epileptic seizure due to unknown cerebral metastases. The morbidity rate was 5.5% and the early reintervention rate 2.8%. There was no lost to follow-up. With a mean 35-month follow-up. 82.2% of the patients were alive after curative surgery. Abdominal wall recurrence at port sites occurred in four patients operated on for a Dukes C cancer before 1994. Prognosis was significantly dependent on cellular differentiation, lymph node extension, pericolic extension and Dukes stage. The 5-year actuarial survival rate, according to Kaplan-Meier method was 65.36%.

CONCLUSION

Laparoscopic colon cancer resection was used by the authors in 92% of patients during 1997. The conversion rate to open laparotomy has been lower than 5% since 1995. Post-operative mortality was 0.4% and post-operative morbidity 5.5%. After curative colonic cancer resection, the 5-year actuarial survival rate was 65%.

Minimally invasive anterior retroperitoneal approach to the lumbar spine. Emphasis on the lateral BAK

STUDY DESIGN

Eighteen patients with lumbar instability from fractures, postlaminectomy syndrome, or infection were treated prospectively with minimally invasive retroperitoneal lumbar fusions.

OBJECTIVES

To determine if interbody Bagby and Kuslich fusion cages and femoral allograft bone dowels can be inserted in a transverse direction via a lateral endoscopic retroperitoneal approach to achieve spinal stability.

SUMMARY OF BACKGROUND DATA

Endoscopic spinal approaches have been used to achieve lower lumbar fusion when instrumentation is placed through a laparoscopic, transperitoneal route. However, complications of using this approach include postoperative intra-abdominal adhesions, retrograde ejaculation, great vessel injury, and implant migration. This study is the first clinical series investigating the use of the lateral retroperitoneal minimally invasive approach for lumbar fusions from L1 to L5.

METHODS

Eighteen patients underwent anterior interbody decompression and/or stabilization via endoscopic retroperitoneal approaches. In most cases, three 12-mm portals were used. Two parallel transverse interbody cages restored the neuroforaminal height and the desired amount of lumbar lordosis was achieved by inserting a larger anterior cage, distraction plug, or bone dowel.

RESULTS

The overall morbidity of the procedure was lower than that associated with traditional "open" retroperitoneal or laparotomy techniques, with a mean length of hospital stay of 2.9 days (range, outpatient procedure to 5 days). The mean estimated intraoperative blood loss was 205 cc (range, 25-1000 cc). There were no cases of implant migration, significant subsidence, or pseudoarthrosis at mean follow-up examination of 24.3 months (range, 12-40 months) after surgery.

CONCLUSIONS

This preliminary study of 18 patients illustrates that endoscopic techniques can be applied effectively through a retroperitoneal approach with the patient in the lateral position. Unlike the patients who had undergone transperitoneal procedures described in previous reports, in these preliminary 18 patients, there were no cases of retrograde ejaculation, injury to the great vessels, or implant migration.