Port site metastases in laparoscopic surgery. First workshop on experimental laparoscopic surgery, Frankfurt 1997

[Surgical smoke: risks and preventive measures]

The application of the advanced technologies in medicine has led to the appearance of new risk factors for health personnel. One of these could be the surgical smoke produced by electrosurgical instruments, ultrasounds or laser. However, there is still insufficient evidence in the published population studies on the detrimental effects of chronic exposure to surgical smoke. The main concern on the possible damage to the health of operating room staff is mainly based on the components currently detected until the date and laboratory experiments. Caution must also be used when extrapolating the results of in vitro studies to daily clinical practice. The organisations responsible for protecting the health of the workers in different countries have still not issued guidelines for the treatment and removal of the surgical smoke generated in both open and laparoscopic procedures. In this article we try to present a view of the consequences that surgical smoke has on health and the preventive measures that can be adopted.

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.

CO2 pneumoperitoneum does not enhance tumor growth and metastasis: study of a rat cecal wall inoculation model

INTRODUCTION

Although many studies have evaluated the effects of carbon dioxide pneumoperitoneum on port site recurrence, little is known about its outcome on tumor growth and metastasis. The effect of pneumoperitoneum with carbon dioxide on cecal tumor growth and metastasis was compared with laparotomy using a rat colon cancer cell line.

METHODS

Time Course Study: Fifty WF/BN F1 hybrid rats were inoculated with 2,000,000 WB2054M5 tumor cells into the cecal wall and explored two to ten weeks after injection. Main Study: 152 rats were randomly assigned either to 6-mmHg CO2 pneumoperitoneum (30 minutes) or 4-cm laparotomy (30 minutes) two weeks after tumor inoculation and were explored four weeks after treatment.

RESULTS

Time Course Study: Thirty-seven (95 percent) of the surviving rats developed a cecal wall tumor, and there was progressive tumor growth and metastasis over the ten-week period. At six weeks, metastasis occurred to the liver in 25 percent, to the lung in 38 percent, and to the lymph node in 63 percent, and peritoneal seeding occurred in 38 percent; this time period was chosen for the main study. Main Study: At the time of treatment (2 weeks), 124 rats were eligible for randomization. One hundred two rats survived the six-week period (50 pneumoperitoneum, 52 laparotomy) and were killed. There were no differences between the CO2 pneumoperitoneum and laparotomy groups regarding cecal tumor growth (1.043 vs. 0.894 g) and metastases to the liver (32 vs. 37 percent), lung (34 vs. 17 percent), lymph node (84 vs. 77 percent), and wound or port (20 vs. 23 percent).

CONCLUSIONS

A cecal wall inoculation model mimics the natural cascade of colon cancer growth and metastasis. CO2 pneumoperitoneum did not affect the tumor growth and metastasis to the liver and other organs when compared with laparotomy in this model.

New therapeutic strategies to avoid intra- and extraperitoneal metastases during laparoscopy: results of a tumor model in the rat

BACKGROUND

Therapeutic strategies to prevent port site recurrences in laparoscopy surgery of malignancies have not been investigated until now.

METHODS

The effects of taurolidine, heparin, and povidone iodine on the growth of rat and human colon adenocarcinoma as well as gallbladder carcinoma were investigated in vitro. Furthermore, cytokine release of growth-stimulating IL-1beta by peritoneal macrophages was measured after incubation with carbon dioxide and additional incubation with the different agents. In the third experiment, prevention of intra- and extraperitoneal metastases by intraperitoneal instillation of the different agents during laparoscopy was investigated in a colon carcinoma model in the rat. Tumor cells were administered intraperitoneally in 100 rats, and pneumoperitoneum (8 mm Hg) was established over 30 min with carbon dioxide. Rats received either tumor cells, cells + heparin, cells + povidone iodine, cells + taurolidine, or cells + taurolidine + heparin.

RESULTS

In vitro, tumor cell growth decreased after incubation with taurolidine, taurolidine/heparin, and povidone iodine. Cytokine release was stimulated by incubation with carbon dioxide and could only be suppressed by incubation with taurolidine in vitro. In vivo, intraperitoneal tumor weight was lower in rats receiving heparin (251 +/- 153 mg) and povidone iodine (134 +/- 117 mg) compared to the control group (541 +/- 291 mg), but even less when taurolidine (79 +/- 82 mg) or taurolidine/heparin (18.3 +/- 30 mg) were instilled.

CONCLUSION

Heparin slightly inhibits intraperitoneal tumor growth in vivo, while povidone iodine and taurolidine cause a significant decrease in tumor cell growth in vitro as well as intraperitoneal tumor growth in vivo. Cytokine release of peritoneal macrophages is only suppressed by taurolidine. Total tumor take and trocar metastases are only suppressed by taurolidine and taurolidine/heparin.

Dual effect of laparoscopy on cell-mediated immunity

Laparoscopic influence on cell-mediated immunity and tumour evolution is controversial. The objective of the present study was to assess tumour growth and immune patterns after laparoscopy on an experimental study. Lewis rats, bearing an intrapancreatic ductal carcinoma randomly underwent one of the following 2-hour procedures: anaesthesia, laparotomy or CO(2) pneumoperitoneum. Cell-mediated immunity was investigated through determination of serum IL1beta concentrations by ELISA and TNFalpha, IL6 and iNOS gene transcriptions in blood white cells and peritoneal cells by RT-PCR 1 day after operation. Tumour growth and spread patterns were assessed on anatomopathological examination 2 weeks after surgery. Tumour growth and spread were unaffected no matter what procedure was applied, but port-site seeding occurred in half of the cases undergoing laparoscopy. No significant change in acute-phase protein response, represented by IL1beta serum concentration, was found after laparoscopy. TNFalpha, IL6 and inducible NO synthase gene transcriptions were enhanced in blood white cells and depressed in peritoneal immune cells after laparoscopy. In our experimental conditions, cell-mediated immune response to CO(2) pneumoperitoneum seems to be a good systemic immune activation and a less acute peritoneal immune response as opposed to control laparoscopy. This early impairment of peritoneal macrophage immune activity, observed after a long-lasting CO(2) pneumoperitoneum, might be responsible for the high rate of port site recurrence.

Impact of laparoscopic colonic resection on tumour growth and spread in an experimental model

BACKGROUND

The influence of surgical manipulation and carbon dioxide pneumoperitoneum on intraperitoneal tumour growth and port-site metastasis during laparoscopic colon resection is still unknown.

METHODS

Some 33 male WAG/Rij rats were randomized into three experimental groups: a laparoscopy group with carbon dioxide pneumoperitoneum (n = 11), a gasless laparoscopy group (n = 11) and a laparotomy group (n = 11). After transanal injection of a tumour cell suspension (1 x 106 CC 531 cells) into the distal colon, a colon segment resection and an end-to-end anastomosis (laparoscopy; intra-abdominal technique) were performed. Tumour growth was scored semiquantitatively 24 days after the operation. Data were analysed by the Kruskal-Wallis test.

RESULTS

The tumour indices from the four locations with the greatest tumour growth were significantly decreased in the laparoscopy group with carbon dioxide pneumoperitoneum compared with the gasless laparoscopy and laparotomy groups (P < 0.01). Port-site metastases were significantly decreased in the carbon dioxide pneumoperitoneum group compared with the gasless laparoscopy group (P = 0.05).

CONCLUSION

A full laparotomy incision promotes greater tumour growth than does carbon dioxide pneumoperitoneum. Surgical manipulation stimulates local tumour spread more than the establishment of a carbon dioxide pneumoperitoneum.

Minimally invasive techniques for colorectal cancer

Laparoscopic approaches are increasingly being applied to colorectal surgical procedures. Initial concerns regarding the existence of benefits from the laparoscopic approach have now been addressed. Even as these were being addressed, however, further concerns arose regarding the appropriateness of this technique in malignancy. Colorectal cancer is the only intra-abdominal malignancy that is knowingly resected employing laparoscopic techniques. This controversy was highlighted by reports of early wound implants. With careful technique, training and experience, however, wound recurrences are rarely seen, suggesting that this phenomenon, in the clinical setting, is primarily technique-related. Lack of rigorous evidence either condemning or supporting the laparoscopic approach for colorectal cancer resulted in the establishment of several large-scale randomized, prospective trials, all currently in progress, that aim to determine if laparoscopic resection of colorectal cancer results in oncologic outcomes comparable to the open approach.