In vitro inhibition of tumour growth in a helium-rich environment: implications for laparoscopic surgery

Effects of Sevoflurane versus Propofol on Endogenous Nitric Oxide Metabolism during Laparoscopic Surgery

For laparoscopic surgery, it is very difficult to assess the effect of different medicines used in the surgical procedure on the surgical results. In the past, doctors could use sevoflurane to numb and calm patients. For decades, this type of treatment has been fairly reliable and effective, but for laparoscopic surgery, the use of sevoflurane can lead to a wide range of blood glucose changes, so in recent years, sevoflurane compared to propofol in laparoscopic surgery on endogenous and nitrogen oxide metabolism has been studied more and more. In this paper, a variety of research methods were used to study the phenomenon of shock and excessive anesthesia encountered by patients in the treatment process. Through observation and drug experiment of patients in different treatment courses and treatment stages, patients were asked to use sevoflurane and propofol to conduct double-blind experiments on their own drug effects. At the same time, through the long-term observation of patients with different diseases and patients who need laparoscopic surgery, the nitrogen oxide metabolism in patients with sevoflurane compared with propofol endogenous was studied and analyzed. Through three groups of different conditions, the experimental group, the blind test group, and the control group were studied. To conclude, in laparoscopic surgery, the use of sevoflurane compared with propofol can have a good impact on the endogenous drug and nitrogen oxide metabolism. It can achieve a good effect on the anesthesia effect of surgery, the maintenance of patient's physical signs and heart rate, which is very beneficial to the operation. Conclusion. Sevoflurane compared with propofol has a good effect on endogenous nitrogen oxide metabolism in laparoscopic surgery.

Effects of a simulated CO2 pneumoperitoneum environment on the proliferation, apoptosis, and metastasis of cervical cancer cells in vitro

BACKGROUND

This study aimed to investigate the growth curve, cell colony formation, cell cycle, apoptosis, anti-anoikis, and ability of invasion, adhesion, and migration of cervical cancer cells after exposure to a model of a simulated CO2 pneumoperitoneum environment with different pressures and at different times.

MATERIAL AND METHODS

The cervical cancer cells were cultured in groups with 8 and 16 mmHg of 100% CO2 for 1, 2, 3, and 4 h in a model of a simulated environment of CO2 pneumoperitoneum. The cells in the control group were cultured in a standard environment. The growth curve was drawn through constant survival cell counts for 7 days, and the group with most obvious change was selected for subsequent experiments to detect cell colony formation, cell cycle apoptosis, and anti-anoikis, and the ability of invasion, adhesion, and migration.

RESULTS

After a brief inhibition, the proliferation of cervical cancer cells was markedly increased and had no relationship with different CO2 pressures. Compared with the control group, the early apoptosis rate in the experimental group was higher, and the ability of invasion, migration, and adhesion decreased significantly.

CONCLUSIONS

Cervical cancer cells stimulated by a CO2 pneumoperitoneum environment in vitro have an increased the ability to proliferate after a short period of inhibition and have reduced abilities of invasion, migration, and adhesion.

IL-17A promotes the migration and invasiveness of cervical cancer cells by coordinately activating MMPs expression via the p38/NF-κB signal pathway

Objective

IL-17A plays an important role in many inflammatory diseases and cancers. We aimed to examine the effect of IL-17A on the invasion of cervical cancer cells and study its related mechanisms.

Methods

Wound healing and matrigel transwell assays were used to examine the effect of IL-17A on cervical cancer cell migration and invasion by a panel of cervical cancer cell lines. The levels of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) were investigated using western blotting. The activity of p38 and nuclear factor-kappa B (NF-κB) signal pathway was detected too.

Results

Here, we showed that IL-17A could promote the migration and invasion of cervical cancer cells. Further molecular analysis showed that IL-17A could up-regulate the expressions and activities of MMP2 and MMP9, and down-regulate the expressions of TIMP-1 and TIMP-2. Furthermore, IL-17A also activates p38 signal pathway and increased p50 and p65 nuclear expression. In addition, treatment of cervical cancer cells with the pharmacological p38/NF-κB signal pathway inhibitors, SB203580 and PDTC, potently restored the roles of invasion and upregulation of MMPs induced by IL-17A.

Conclusion

IL-17A could promote the migration and invasion of cervical cancer cell via up-regulating MMP2 and MMP9 expression, and down-regulating TIMP-1 and TIMP-2 expression via p38/NF-κB signal pathway. IL-17A may be a potential target to improve the prognosis for patients with cervical cancer.

Effects of simulated carbon dioxide and helium peumoperitoneum on proliferation and apoptosis of gastric cancer cells

AIM

To investigate the effects of carbon dioxide (CO(2)) and helium insufflation administered at different pressures on the growth and apoptosis of cultured human gastric cancer cells.

METHODS

The gastric cancer cells MKN-45 were exposed to a CO(2) and helium environment maintained at different pressures (0, 5, 10 and 15 mmHg). The cells were exposed to simulated pneumoperitoneum environment for 4 h, and pH of the culture media was measured after it was moved to normal conditions for 0, 2, 4, 6 and 8 h. Proliferation viability of MKN-45 was examined by 3-[4,5Dimethylthiazol-2-yl],5-diphenyltetrazolium bromide or triazolyl blue (MTT) assay after it was moved to normal conditions. Apoptotic ratio was measured by Annexin V-FITC/PI double labelled staining.

RESULTS

The pH of media was acid and recovered to normal after 4 h in the CO(2) group while it was basic in the helium group. There was no difference between CO(2) groups (under 10 mmHg ) and control group (P > 0.05) in the proliferative viability of the cells. The cultured cells exposed to 15 mmHg CO(2) environment grew more slowly than control group from 4 to 7 d (P < 0.01 ) while there was no difference from 1 to 3 d (P > 0.05). The proliferative viability in helium group was not obviously different from the control group (P > 0.05). The apoptotic ratio of the cultured cells was markedly higher than that of the control group (P < 0.01) at 10 and 15 mmHg CO(2) insufflation pressure. In helium group, the apoptotic ratio was not obviously different from the control group (P > 0.05).

CONCLUSION

There is no obvious effect in the proliferation and apoptosis of MKN-45 cells under 10 mmHg CO(2) insufflation pressure and helium in any pressure. Fifteen mmHg CO(2) insufflation pressure can inhibit the proliferation of the cells and improve apoptosis.

The uses of helium and xenon in current clinical practice

The noble gases have always been an enigma. Discovered late in the history of chemistry and in seemingly small quantities in our atmosphere, they are some of the most unreactive elements known. However, despite being extremely inert, the noble gases (helium, neon, argon, krypton, xenon and radon) have found diverse and ever expanding applications in medicine. Of all of them, the gases that have found the greatest number of uses in the field of anaesthesia and related specialties are helium and xenon. This review focuses on the history of the discovery of both gases, their unique physicochemical properties and describes their uses in clinical practice with particular emphasis on those applicable to anaesthesia.

Impact of different pressures and exposure times of a simulated carbon dioxide pneumoperitoneum environment on proliferation and apoptosis of human ovarian cancer cell lines

BACKGROUND

This study aimed too evaluate the proliferation and apoptosis of human ovarian cancer cell lines HO8910 and SKOV3 after exposure to a simulated laparoscopic carbon dioxide (CO2) pneumoperitoneum environment at different pressures and lengths of exposure time.

METHODS

The effects of the simulated laparoscopic CO2 pneumoperitoneum environment at different CO2 pressures (0-16 mmHg) and exposure times (1-4 h) on tumor cell growth and apoptosis were assessed by 3-[4,5-Dimethylthiazol]-2; 5-diphenyltetrazolium bromide (MTT) chromometry and proliferative index (PI) staining or Annexin V and PI double-staining flow cytometry. Cells cultured in a standard environment were used as the control group.

RESULTS

In this study, HO8910 cell growth tended to slow down with the increase in CO2 pressure and exposure time. A significantly lower PI was observed at 72 h of culture after exposure to both 8 and 16 mmHg of pressure, as compared with the control and 0 mmHg pressure group (p < 0.05). The PI of SKOV3 cells tended to decline after exposure. Significantly lower PI was observed in the group with exposure to 16 mmHg for 4 h over a 72-h period, as compared with the control groups exposed to 0 mmHg (p < 0.05). The inhibition of cell growth was associated with an increase in the proportion of cells at stage G1. The apoptotic index and the percentage of apoptotic cells tended to increase with an increase in pressure and a prolonged time of exposure.

CONCLUSIONS

The results suggest inhibited cell proliferation and increased cell apoptosis of human ovarian cancer cells were positively related to CO2 pressure and exposure time.

Effect of acidosis on expression of mesothelial cell plasminogen activator inhibitor type-1

BACKGROUND

Abdominal mesothelial cells are exposed to carbon dioxide during laparoscopy. Previous data indicate that carbon dioxide increases release and expression of plasminogen activator inhibitor type-1 (PAI-1) and induces acidification.

METHODS

To assess the impact resulting from a range of pH, human mesothelial cells were exposed to culturing media balanced to pH levels of 6.0 to 8.0 for 90 min. Samples from cell media were withdrawn at several time points. Concentrations of PAI-1 and PAI-1 activity were measured using enzyme-linked immunoassay techniques. To focus on the effect of clinically relevant pH, cells were subjected to pH 6.4 and 7.4. Samples were withdrawn for PAI-1 assessments and for PAI-1 mRNA analyses.

RESULTS

During exposure to various levels of pH, PAI-1 secretion and activity were variable. However, 5 h after exposure, greater concentration and activity of PAI-1 were observed in acidified cultures. More PAI-1 mRNA was isolated after exposure of cells to a pH of 6.4, apparently indicating transcriptional regulation.

CONCLUSIONS

Mesothelial cells seem to respond to acidification by an increased release and production of PAI-1 in vitro.

Exposure to carbon dioxide and helium reduces in vitro proliferation of pediatric tumor cells

BACKGROUND

Minimally invasive techniques are increasingly applied to children with malignant tumors. We showed previously that CO(2) used for pneumoperitoneum modulates the function of macrophages and polymorphonuclear cells via direct effects and via acidification. Numerous in vitro and small animal model studies also confirmed an alteration of the behavior of several types of adult tumor cells by CO(2). The impact of CO(2) and other gases used for pneumoperitoneum on the behavior of various pediatric tumors has not yet been determined.

METHODS

Cell lines of neuroblastoma (IMR 32, SK-N-SH, Sy5y), lymphoma (Daudi), hepatoblastoma (Huh 6), hepatocellular carcinoma (Hep G2), and rhabdomyosarcoma (Te 671) were incubated for 2 h. Incubation was performed with 100% CO(2), 100% helium, and 5% CO(2) as control. Cell proliferation was determined by the MTT-assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] by actively growing cells to produce a blue formazan product. The MTT-assay was performed before, directly after incubation, and daily for 4 days. Vitality of the cells was determined by trypan blue. The extracellular pH during incubation was measured during gas exposition every 10 min using Bayer Rapid Lab 855.

RESULTS

CO(2) for 2 h significantly decreased the proliferation of neuroblastoma, lymphoma, hepatoblastoma, and hepatocellular carcinoma cells. This decrease persisted over 4 days in neuroblastoma, lymphoma, and hepatocellular carcinoma cells. The CO(2) had no impact on hepatoblastoma and rhabdomyosarcoma cells. Helium had a similar effect on neuroblastoma cells. After 4 days, a significant decrease of cell activity was found in two neuroblastoma cell lines and in hepatoblastoma cells. Helium had no effect on lymphoma and hepatocellular carcinoma cells. The extracellular pH was 6.2 during incubation with CO(2), and 7.6 during incubation with helium.

CONCLUSION

CO(2) and helium may affect the proliferation of some pediatric tumor cell lines in vitro. However, some of these effects and the impact on the extracellular pH are differential. The role of pH modulation, hypoxia and direct effects of gases remain to be investigated before a general recommendation on the use of minimally invasive techniques in pediatric oncology can be given.

Effects of pneumoperitoneal gases and pressures on transitional cell carcinoma adhesion, growth, apoptosis and necrosis: an in vitro study

PURPOSE

We studied the effects of insufflation gas and pressure on the adhesion, growth, apoptosis and necrosis of transitional cell carcinoma (TCC) in an in vitro model.

MATERIALS AND METHODS

Tumor adhesion and cell growth of AY-27 rat TCC was measured after 3-hour incubation with CO2, N2 and He insufflation at different pressures (0, 10 and 15 mm Hg) in vitro. The effects of these gases on the rate of tumor cell apoptosis and necrosis were compared.

RESULTS

In vitro the tumor adhesion rate was lowest with CO2 and highest with N2. Higher gas pressures resulted in decreased adhesion rates for CO2 and He but increased adhesion rates for N2. N2 enhanced tumor cell proliferation at all pressures studied. He and CO2 resulted in an initial increase in cell proliferation in the first 24 hours, followed by a decrease in tumor growth. Extracellular medium turned acidic in CO2 (pH 6.27 to 6.39) but basic in N2 and He (pH 8.39 to 8.84). At all insufflation pressures studied apoptosis and necrosis rates were increased in the first 24 hours, followed by a decrease for CO2 and N2. He resulted in increasing apoptosis and necrosis throughout the study period.

CONCLUSIONS

The type of gas and insufflation pressure affects cell adhesion and tumor growth. There was a significant increase in tumor adhesion and proliferation with N2 insufflation compared with CO2 and He at 0 to 15 mm Hg pressures. CO2 demonstrated the greatest decrease in TCC adhesion and proliferation at 15 mm Hg pressure. Apoptosis and necrosis were highest for He compared with the other gases.

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.

Increased tumor growth after high pressure pneumoperitoneum with helium and air

BACKGROUND

Tumor growth appears proportional to the pressure of carbon dioxide insufflation during laparoscopic surgery. Air and helium are alternative insufflation gases. The objective of this study is to assess tumor growth after air and helium insufflation at different pressures.

METHOD

Ninety-six WAG rats were allocated to either air or helium. In both arms, rats were randomly exposed to a one hour gasless procedure, or to 4 mm Hg, 10 mm Hg, or 16 mm Hg insufflation. At the start of the procedure, 500,000 CC531 tumor cells were injected intraperitoneally. After three weeks, intraperitoneal tumor growth was assessed.

RESULTS

Higher insufflation pressures were associated with greater tumor growth. No difference of tumor growth between air and helium insufflation was found.

CONCLUSION

In this experimental model, insufflation pressure appeared to have a greater impact on tumor growth than the type of gas. Further studies are necessary but it seems prudent to recommend employment of lower insufflation pressures in laparoscopic oncologic surgery.

Influence of different gases used for laparoscopy (helium, carbon dioxide, room air, and xenon) on tumor volume, histomorphology, and leukocyte-tumor-endothelium interaction in intravital microscopy

BACKGROUND

Previous studies indicate that helium pneumoperitoneum used for laparoscopic surgery suppresses whereas carbon dioxide pneumoperitoneum increases postoperative tumor growth. The pathomechanisms of decreased tumor growth by helium are unknown. This study was designed to examine the effect of the gases helium, carbon dioxide (CO(2)), and air, and xenon, which can be used to induce pneumoperitoneum in laparoscopy on tumor volume, histomorphology, and leukocyte-endothelium interaction measured by intravital microscopy in rats with implanted liver malignoma (Morris hepatoma 3924A).

METHODS

In 46 rats, Morris hepatoma 3294A cells were implanted intrahepatically. After implantation, rats were randomized into two main groups. In the first main group, 10 animals were prepared for examination of leukocyte-endothelium interaction by intravital video microscopy and were randomized into two groups. Five days after implantation they underwent laparoscopy using either helium (n = 5) or CO(2) (n = 5). Ten days after implantation the rats underwent intravital video microscopy to assess leukocyte-endothelium interaction in the tumor and liver vessels. In the second main group 36 rats were prepared for examination of tumor volume arid histomorphology. They were randomized into five groups. Five days after implantation they underwent laparoscopy using helium (n = 7), carbon dioxide (n = 7), room air (n = 7), or xenon (n = 8). The control group (n = 7) received anesthesia only. Rats were killed 10 days after tumor implantation to assess tumor volume and histomorphology.

RESULTS

Compared to the control group or groups that received CO(2), room air, or xenon for pneumoperitoneum, the establishment of helium pneumoperitoneum caused a significantly smaller tumor volume (Kruskal-Wallis test, p = 0.001; median tumor-volume: control group, 44 mm(3); helium 19 mm(3)). There was no significant difference in histomorphology between the groups. There was only a statistically significant difference in the development of central tumor necrosis in accordance to tumor volume (Mann-Whitney test, p = 0.03). In the tumor samples, roller counts were statistically significantly higher in the helium group compared to the CO(2) group (p = 0.04). For sticker counts, no statistically significant effects due to liver/tumor (p = 0.13) or treatment (p = 0.48) were observed.

CONCLUSIONS

There was a significant decrease in tumor volume using helium pneumoperitoneum for laparoscopy compared to the other gases. Here, we demonstrate that suppression of tumor growth is not due to variation of histomorphology. It seems that helium pneumoperitoneum effects a higher leukocyte-endothelium interaction and thereby a higher immune activation. This could be one explanation for the statistically significantly smaller tumor volume after laparoscopy with helium compared to laparoscopy with CO(2).

The Comparison of the Oxidative Stress Effects of Different Gases and Intra-abdominal Pressures in an Experimental Rat Model

BACKGROUND

Laparoscopy is used for almost all types of abdominal surgery because of its advantages, which include shorter postoperative hospital stay. However, pneumoperitoneum used to facilitate the visual field has severe metabolic, hemodynamic, and inflammatory consequences depending on the pressure level and the gas used. Helium (He), an inert gas, has been recommended for establishment of pneumoperitoneum since it does not alter the blood pH and PCO(2). Yet the oxidative response after He insufflation remains unknown. This study was undertaken to compare the levels of free radical production and antioxidant status following He and CO(2) pneumoperitoneum at different intra-abdominal pressure values.

MATERIALS AND METHODS

The subjects were 40 Sprague-Dawley male rats randomized to the following groups: He 10 (n = 8) was subjected to He pneumoperitoneum at 10 mm Hg for 60 minutes; He 15 (n = 8) was subjected to He pneumoperitoneum at 15 mm Hg for 60 minutes; CO(2) 10 (n = 8) was subjected to CO(2) pneumoperitoneum at 10 mm Hg for 60 minutes; CO(2) 15 (n = 8) was subjected to CO(2) pneumoperitoneum at 15 mm Hg for 60 minutes; and Control (n = 8) was subjected to sham operation without pneumoperitoneum. At the end of the experiment blood samples were obtained and plasma malondialdehyde, carbonyl, and sulphydryl levels were measured.

RESULTS

CO(2) pneumoperitoneum produced higher malondialdehyde and carbonyl responses and sulphydryl consumption compared to He, especially at 15 mm Hg (P = 0.01, P = 0.01, and P = 0.059, respectively).

CONCLUSION

Helium seems to limit the postoperative oxidative response following laparoscopy.

The impact of carbon dioxide and helium insufflation on experimental liver metastases, macrophages, and cell adhesion molecules

BACKGROUND

Laparoscopic insufflation, proposed to reduce hepatic perfusion, may enhance hepatic tumor spread. It is unknown whether intraabdominal pressure or the gas itself influences hepatic tumor growth. In contrast to carbon dioxide, the alternative gas helium is believed to reduce malignant cell growth.

METHODS

For this study, 36 WAG/Rij rats were randomized in two experimental groups. The animals were laparoscopically insufflated with carbon dioxide ( n = 19) or helium gas ( n = 17). Liver metastases were induced by laparoscopic injection of 50,000 CC531 cells into the portal vein. Macroscopic and microscopic analyses of CC531 tumor cell growth, macrophages, and CD44v5, v6 were performed. Data were analyzed by Kruskal-Wallis, Dunn, and Holm tests.

RESULTS

No significant differences in macroscopic and microscopic analyses were found between carbon dioxide and helium gas insufflations ( p > 0.05).

CONCLUSIONS

Recent studies have shown that insufflation with carbon dioxide may result in increased hepatic tumor growth. The current study comparing carbon dioxide and helium insufflations could show for the first time either oncologic nor immunologic differences in relation to the liver between two different gases. In conclusion, elevated intraabdominal pressure during gas insufflation is responsible for hepatic disadvantages during pneumoperitoneum, not carbon dioxide gas itself.

Influence of different gases used for laparoscopy (helium, carbon dioxide, room air, xenon) on tumor volume, proliferation, and apoptosis

BACKGROUND

Previous reports suggest that helium pneumoperitoneum used for laparoscopic surgery suppresses postoperative tumor growth. The present study was designed to determine the effects of gases used in laparoscopy on tumor volume, proliferation, and apoptosis in rats with implanted malignoma.

METHODS

In 36 rats Morris hepatoma 3294A cells were implanted intrahepatically. Then, after 5 days, they underwent laparoscopy using helium ( n = 7), CO(2) ( n = 7), room air ( n = 7), or xenon ( n = 8). One group received anesthesia only ( n = 7). Rats were killed 10 days after implantation to assess tumor volume, proliferation, and apoptosis.

RESULTS

Helium pneumoperitoneum caused a significant smaller tumor volume compared to other groups (Kruskal-Wallis test: p = 0.001; median tumor volume: control: 44 mm3; helium: 19 mm3). There was no significant difference in tumor cell proliferation (PCNA) and apoptosis (TUNEL reaction) between the groups.

CONCLUSIONS

There was a significant decrease of tumor volume using helium pneumoperitoneum compared to the other gases, but no decreased tumor cell proliferation or increased tumor cell apoptosis.

[Prevention of port-site metastasis after laparoscopy]

Port-site metastasis is a major complication of surgical laparoscopy for gynaecologic oncology. Aetiology of port-site metastases is multifactorial. Surgical conditions and laparoscopic environment were determinant. Several means of prevention were evaluated to prevent occurrence of port-site metastases. Aim of this review is to report optimal surgical conditions, laparoscopic environment and means of prevention to decrease risk of port-site metastases.

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.

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.