Exfoliated cells and in vitro growth in colorectal cancer

Impact of anastomotic leakage on oncological outcome after rectal cancer resection

BACKGROUND

: Anastomotic leakage has a major impact on morbidity and mortality in rectal cancer surgery. Its relevance to oncological outcome is controversial. This observational study investigated the influence of anastomotic leakage on oncological outcome.

METHODS

: Data for 1741 patients undergoing curative resection of rectal cancer (located less than 12 cm from the anal verge) with normal healing were compared with those for 303 patients who experienced anastomotic leakage. Morbidity, mortality and long-term oncological outcomes were analysed.

RESULTS

: Median follow-up was 40 months. Patients with anastomotic leakage had a higher postoperative mortality rate than those with no leakage (4.3 versus 1.2 per cent; P < 0.001). Patients with leakage necessitating surgical treatment had a higher 5-year local recurrence rate (17.5 versus 10.1 per cent; P = 0.006) and a lower 5-year disease-free survival rate (70.9 versus 75.4 per cent; P = 0.020) than those without leakage. Patients with anastomotic leakage not requiring surgical intervention did not have a worse oncological outcome.

CONCLUSION

: A negative prognostic impact of anastomotic leakage on local recurrence and disease-free survival was found only for patients with leakage needing surgical revision.

Efeitos da injeção de solução bicarbonatada de ácido acetilsalicílico em mucosa colorretal de coelhos, com vistas a aplicação no preparo pré-operatório do cólon

INTRODUÇÃO: A recidiva local no câncer colorretal tem como principal causa o implante de células tumorais nas anastomoses. 11-15 Dessa maneira, lavagem química do lúmen intestinal é preconizada para evitar tanto o implante quanto à recidiva local. 11-28 Em estudos prévios constatamos que a solução bicarbonatada de ácido acetilsalicílico tem efeitos citolíticos e anti-tumorais in-vitro.31 OBJETIVOS: Avaliar a toxicidade da solução de aspirina na mucosa colônica de coelhos com o objetivo de usá-la no preparo intestinal de portadores de câncer colorretal. MATERIAIS E MÉTODOS: Foram utilizados 20 coelhos. Um clampe vascular foi colocado acima do cólon sigmóide. Os animais foram submetidos a um enema com 50 ml da solução de aspirina ou soro fisiológico de acordo com o grupo. Os animais foram sacrificados ao término do procedimento ou tardiamente de acordo com o grupo. RESULTADOS: A solução de aspirina não altera a mucosa colônica de coelhos. CONCLUSÃO: O uso da solução bicarbonatada de ácido acetilsalicílico no preparo intestinal de portadores de câncer colorretal é clinicamente possível.

Can intra-operative intraperitoneal free cancer cell detection techniques identify patients at higher recurrence risk following curative colorectal cancer resection: a meta-analysis

BACKGROUND

Accurate staging of colorectal cancer is important for predicting prognosis and guiding treatment. This study uses meta-analysis to investigate if the pre- or post-resection detection of intraperitoneal free cancer cells can predict recurrence in patients undergoing curative colorectal cancer surgery.

METHODS

A literature search was performed on all studies between January 1990 and July 2007 comparing the detection of intraperitoneal free cancer cells either pre- or post-resection with prognosis in colorectal cancer. The following prognostic outcomes were meta-analyzed: overall recurrence rate and local recurrence rate. A random-effect model was used and heterogeneity was assessed.

RESULTS

Nine studies reporting on a total of 1182 subjects matched the selection criteria. Free cancer cells were detected prior to tumor resection in 125/822 (15.2%) of patients and following resection in 64/533 (12%) of patients. Preresection, the absence of tumor cells was associated with a lower overall recurrence (25.2%) compared to the presence of tumor cells [46.4%, odds ratio (OR) = 0.41, confidence interval (CI) 0.19-0.88]; as well as a significantly lower local recurrence (12.2% versus 21.1%, OR = 0.42, CI 0.21-0.82). Postresection, the absence of tumor cells also resulted in significantly lower overall recurrence (17.3%) when compared to the presence of tumor cells (52.6%, OR = 0.07, CI 0.03-0.18).

CONCLUSIONS

The detection of intraperitoneal free cancer cells is associated with higher recurrence and poorer prognosis. Use of these techniques can identify patients at higher recurrence risk. This could be particularly valuable in stage II disease to identify patients who may benefit from adjuvant chemotherapy.

Is rectal washout necessary in anterior resection for rectal cancer? A prospective clinical study

BACKGROUND

Implantation of exfoliated malignant cells has been suggested as a possible mechanism of tumor recurrence in colorectal anastomoses that might be prevented by cytocidal washout. The aim of our study was to assess whether malignant cells are likely to be collected by a circular stapler introduced transanally to perform an anastomosis and to observe local recurrences during follow-up, with special attention to the washout status of patients.

METHODS

Between May 1999 and March 2004, 96 patients with carcinoma of the rectum and distal sigmoid colon undergoing anterior resection under the care of three surgeons (only one of whom routinely performed rectal washout) were prospectively studied. While 38 patients had rectal washout with 5% povidone-iodine before anastomosis, 58 patients did not. A circular stapler was used for anastomosis, and the stapler was immediately rinsed in 100 ml of saline. The fluid was then classified as "acellular," "malignant cells identified," or "benign cells identified" by pathologists.

RESULTS

Malignant cells were collected from the circular stapler after use in 3 patients (8%) on whom rectal washout was performed and in 2 (3%) patients who did not have rectal washout performed (P=0.631). Three patients (8%) in the washout group developed local recurrence, and 2 patients (3.4%) in the no-washout group had local recurrence (one was anastomotic recurrence) (P=0.338). The median follow-up time was 23 (range: 9-70) months.

CONCLUSIONS

There were no differences in terms of the number of patients who had malignant cells collected from the circular stapler and local recurrence rates between the two groups. Although this is not a randomized study and size and mean follow-up time of the study were not sufficient, our results did not offer rational arguments in support of intraoperative rectal washout when a circular stapler is used after low anterior resection for carcinoma. Because of the limitations of our study, however, we are unable to arrive at a definite conclusion regarding rectal washout. There is a need for a randomized, controlled, large-scale, multicenter trial to establish the clinical relevance of intraoperative rectal washout.

Prognostic significance of CEA levels and positive cytology in peritoneal washings in patients with colorectal cancer

OBJECTIVE

The aims of this prospective study were to determine carcinoembryonic antigen (CEA) levels and incidence of cytology in peritoneal washings of patients with colorectal cancer, correlate the results with various histopathological factors and determine their significance as prognostic factors of the disease.

METHODS

From 1992 to 1999, 98 patients with adenocarcinoma of the colon or intraperitoneal rectum underwent curative surgery and enrolled in this study.

RESULTS

Overall, 25 (26.3%) of 95 patients were found to have positive cytology. The proportion of patients with positive cytology was higher in the recurrence group (36.4%) than in the groups of 5-year survival and hepatic metastases (24.6% and 26.3%, respectively), but this difference was not significant. The 5-year survival group had the lowest peritoneal CEA levels compared with the other groups, but this difference was not significant. Peritoneal cytology and CEA level alone were not sensitive, specific or accurate enough indicators in predicting survival, hepatic metastases or local recurrence. The analysis of patients with positive cytology and high peritoneal CEA level revealed that their combination can predict local recurrence with accuracy of 85%.

CONCLUSIONS

The presence of free malignant cells, as detected by cytology and CEA level, in the peritoneal cavity of patients with resectable colorectal cancer had no detectable impact on survival, hepatic metastases or local recurrence rate. However, local recurrence can be predicted with accuracy of 85% in patients who have positive cytology and high peritoneal CEA level at the same time.

Serosal involvement in gastrointestinal cancer: its assessment and significance

There is an increasing burden upon diagnostic histopathologists to identify accurately factors of prognostic and therapeutic implication in gastrointestinal cancer. It is perhaps partly because of the use of rigid sequential staging systems, such as the Dukes' classification, that some factors, perhaps most notably involvement of surgical margins (especially in rectal cancer) and serosal involvement (particularly in oesophageal, colonic and rectal cancer), have been relatively neglected until more recently. This is surprising and concerning because both of these pathologically derived parameters strongly correlate with subsequent locoregional recurrence and, ultimately, with prognosis. Whilst the occurrence and significance of serosal involvement have been well recognized in gastric cancer for many years, relatively little attention has been paid to the phenomenon in oesophageal cancer and yet both pleural and peritoneal involvement may be comparatively commonly identified in oesophageal cancer. Serosal involvement and transperitoneal spread are also of considerable prognostic importance in primary appendiceal carcinoma. Only more recently has the significance of serosal involvement been appreciated in colonic and rectal cancer. In the colon, the phenomenon is now recognized to be one of the most important factors in predicting transperitoneal spread and overall prognosis. Furthermore, there is increasing interest in alternative novel strategies, including intraperitoneal chemotherapy and radical peritoneal surgery, as legitimate therapeutic options in many gastrointestinal cancers.

Prognosis after anastomotic leakage in colorectal surgery

INTRODUCTION

Anastomotic leakage is a major complication of colorectal surgery causing a significant increase in 30-day mortality. The long-term prognosis of anastomotic leakage is poorly documented. This study was designed to assess whether anastomotic leakage affects five-year survival and local recurrence.

METHODS

A total of 5,173 patients were recruited to the Wessex Colorectal Cancer Audit during the period September 1991 to August 1995 (prospective data, 5-year follow-up). The effect of anastomotic leakage on five-year survival and local recurrence was analyzed using Kaplan-Meier curves and the log-rank test.

RESULTS

A total of 1,834 patients underwent a curative resection with an anastomosis (anastomotic leak = 71; 3.9 percent): 30-day mortality: 18.3 percent in the leak group, and 3.5 percent in the nonleak group (P < 0.001); local recurrence: 19 percent in the leak group, and 9.8 percent in the nonleak group (P = 0.018). A total of 1,201 patients underwent colonic anastomosis (anastomotic leak = 31; 2.6 percent). There was no significant difference in local recurrence or five-year survival between the leak and nonleak groups. A total of 633 patients underwent rectal anastomosis (anastomotic leakage = 40; 6.3 percent): 30-day mortality: 10 percent in the leak group, and 2 percent in the nonleak group (P = 0.014); cumulative five-year estimate of local recurrence: 25.1 (95 percent confidence interval, 9.6-40.5) percent in the leak group, and 10.4 (95 percent confidence interval, 7.7-13) percent in the nonleak group (P = 0.007). Cumulative five-year estimate of overall survival: 52.8 (95 percent confidence interval, 36.1-69.4) percent in the leak group, and 63.9 (95 percent confidence interval, 59.9-67.9) percent in the nonleak group (P = 0.19).

CONCLUSIONS

After rectal anastomosis, an anastomotic leak is associated with a significant increase in local recurrence.

Practice parameters for the management of rectal cancer (revised)

The American Society of Colon and Rectal Surgeons is dedicated to assuring high-quality patient care by advancing the science, prevention, and management of disorders and diseases of the colon, rectum, and anus. The Standards Committee is composed of Society members who are chosen because they have demonstrated expertise in the specialty of colon and rectal surgery. This Committee was created to lead international efforts in defining quality care for conditions related to the colon, rectum, and anus. This is accompanied by developing Clinical Practice Guidelines based on the best available evidence. These guidelines are inclusive, and not prescriptive. Their purpose is to provide information on which decisions can be made, rather than dictate a specific form of treatment. These guidelines are intended for the use of all practitioners, health care workers, and patients who desire information about the management of the conditions addressed by the topics covered in these guidelines. It should be recognized that these guidelines should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all of the circumstances presented by the individual patient.

Impact of taurolidine on the growth of CC531 coloncarcinoma cells in vitro and in a laparoscopic animal model in rats

BACKGROUND

The object of this study was to examine the effect of taurolidine on intraabdominal tumor growth in a laparoscopic animal model. We tested the cytotoxic, antiadhesive, and anti-invasive effects of this substance on CC531 adenocarcinoma cells in vitro and in vivo using WAG rats.

METHODS

For in vitro experiments, Transwell dual chambers with polycarbonate filters coated with 100 microg/cm2 Matrigel were used to investigate the effects of 5, 10, and 20 microl of 2.0% taurolidine on the invasion of 1 x 10(5) CC531 adenocarcinoma cells. For the adhesion assays, tumor cells were applied onto microtiter plates coated with 5, 10, and 20 microl taurolidine and 0.9% NaCl solution for the control group subsequently. For in vivo experiments, 40 WAG rats were randomized into three therapy groups and one control group. All animals underwent laparoscopy and received 1 ml of CC531 adenocarcinoma cells (5 x 10(6) cells/ml) intraabdominally at the beginning of the procedure. According to the randomization, the rats were administered taurolidine with different concentrations or 1 ml of 0.9% NaCl solution for the control group. After 21 days, the animals were killed and the intraabdominal tumor weight was determined.

RESULTS

For the in vitro experiments, we found a moderate cytotoxicity and a significant inhibition of tumor cell adhesion and invasion (p < 0.01) by all taurolidine concentrations used in the assay. For in vivo experiments, the application of all concentrations of taurolidine significantly decreased the intraperitoneal tumor weight (p < 0.001).

CONCLUSION

Taurolidine significantly decreases adhesion and invasion of CC531 adenocarcinoma cells in vitro and significantly diminishes tumor growth in vivo. This may offer additional therapeutic options for laparoscopic surgery for colorectal cancer.

Free colorectal cancer cells on the peritoneal surface: correlation with pathologic variables and survival

BACKGROUND

Clinicopathologic staging of colorectal cancer remains the best predictor of survival. Prognostication for an individual with colorectal cancer remains elusive. This study was designed to investigate the incidence of free surface colorectal cancer cells detected by cytology during elective open curative resection, to correlate their presence with particular clinicopathologic variables and determine whether their presence was predictive of cancer-specific survival.

METHODS

Over a six-year period in one institution, all elective colon and intraperitoneal rectal cancer specimens were assessed during primary resection for the presence of free colorectal cancer cells by means of a simple and tested specimen imprint cytology methodology. Clinicopathologic variables were assessed prospectively and blinded to cytology results. All patients were followed up routinely until death and if the patient was not seen within the last six months, information was obtained from the New South Wales Registry of Births, Deaths and Marriages in Australia.

RESULTS

Overall, 26 of 281 (9.25 percent) colorectal cancers had positive cytology for cancer cells on the peritoneal surface of the bowel. Poorly differentiated tumors were significantly associated with positive cytology. Tumor penetration, presence of vascular or neural invasion, mucinous characteristics, lymph node status, and operative procedure performed were not statistically significant predictors of positive cytology. Overall, 43 of the 281 patients (15.3 percent) died during the mean follow-up period of 49.2 months from cancer-related deaths. Of these patients, 8 had positive cytology and 35 had negative cytology results. Cancer-specific survival assessed with the log-rank test was significantly associated with positive cytology in univariate (P = 0.008) and multivariate analysis (P < 0.001).

CONCLUSION

In this study, the presence of free surface colorectal cancer cells has been shown to be predictive of survival and is independent of direct peritoneal invasion and lymph node status. Thus, further assessment of this simple prognostic variable is warranted and selection of patients with positive cytology for possible adjuvant therapies may be beneficial.

Distilled water peritoneal lavage after colorectal cancer surgery

PURPOSE

Tumor cells exfoliated into the peritoneal cavity during colorectal cancer surgery are viable and tumorigenic and may contribute to peritoneal recurrence. Although commonly used, the tumoricidal effectiveness of antiseptics in peritoneal lavage is doubted because of their chemical alteration by peritoneal secretions. In contrast, osmotic lysis by incubation in distilled water may offer an effective tumoricidal activity. Data defining the susceptibility of colorectal carcinoma cells to osmotic lysis are lacking and hence there is no consensus on optimal lavage methodology.

METHODS

We examined the cytocidal activity of water on colorectal cancer cell lines in culture and determined the effect of peritoneal secretions in vivo on the tumoricidal effectiveness of water.

RESULTS

Incubation of cells in distilled water resulted in cell lysis, with 100 percent lysis achieved after 14 minutes of incubation. In vivo, contamination of lavage water by peritoneal secretions produced a resultant solution with an osmolality of 50 mM. Sequential lavages reduced this contamination, enabling a final resultant solution with an osmolality of 10 mM, which produced 100 percent cell lysis after 32 minutes of incubation.

CONCLUSIONS

Current peritoneal lavage methodology is inadequate because complete cell lysis requires water incubation for longer time periods than is currently practiced. Solutions to this problem are discussed.

Irrigation volume determines the efficacy of "rectal washout"

PURPOSE

Rectal stump washout has been recommended to prevent implantation of exfoliated malignant cells in the anastomosis after anterior resection for rectal cancer. The aim of this study was to investigate its efficacy, particularly the extent to which the volume of irrigation fluid might influence the efficacy of tumor cell elimination and whether tumor characteristics might influence the result.

METHODS

The study comprised 30 consecutive patients operated on by anterior resection for rectal cancer. After cross-clamping the rectum below the tumor, a washout sample was collected for examination after every incremental 500 ml of saline irrigation up to 2 liters. The presence of shed cancer cells was correlated with the washout volume and tumor characteristics.

RESULTS

Cancer cells were found in 29 of 30 patients (97 percent) in the first sample of irrigation fluid and decreased gradually in frequency and number with increasing irrigation volumes. No cancer cells were demonstrated after 1.5 liters of irrigation in patients with tumor below the peritoneal reflection, whereas cancer cells were still present in one-fourth of the patients with tumor located above the peritoneal reflection. Finally, only a small number of cancer cells was confirmed in one patient after 2 liters of irrigation.

CONCLUSIONS

The irrigation volume determined the efficacy of rectal washout. With our method, 1 1/2 liters of saline irrigation appears to clear contents from cancer cells in patients with tumors below the peritoneal reflection whereas at least 2 liters is recommended for patients with tumor above the peritoneal reflection.

Anastomotic leakage is predictive of diminished survival after potentially curative resection for colorectal cancer

OBJECTIVE

The aim of this study was to determine whether anastomotic leakage has an independent association with overall survival and cancer-specific survival.

SUMMARY BACKGROUND DATA

There are many known prognostic indicators following surgery for colorectal cancer (CRC). However, the impact of anastomotic leakage has not been adequately assessed.

METHODS

Consecutive patients undergoing resection between 1971 and 1999 were recorded prospectively in the Concord Hospital CRC database. Total anastomotic leakage was defined as any leak, whether local, general, or radiologically diagnosed. Patients were followed until death or to December 31, 2002. The association between anastomotic leakage and both overall survival and cancer-specific survival was examined by proportional hazards regression with adjustment for other patient and tumor characteristics influencing survival. Confidence intervals (CI) were set at the 95% level.

RESULTS

From an initial 2980 patients, 1722 remained after exclusions. The total leak rate was 5.1% (CI 4.1-6.2%). In patients with a leak, the 5-year overall survival rate was 44.3% (CI 33.5-54.6%) compared to 64.0% (CI 61.5-66.3%) in those without leak. In proportional hazards regression-after adjustment for age, gender, urgent resection, site, size, stage, grade, venous invasion, apical node metastasis and serosal surface involvement-anastomotic leakage had an independent negative association with overall survival (hazard ratio [HR] 1.6, CI 1.2-2.0) and cancer-specific survival (HR 1.8, CI 1.2-2.6).

CONCLUSION

Apart from its immediate clinical consequences, anastomotic leakage also has an independent negative association with survival.

Anastomotic leakage is predictive of diminished survival after potentially curative resection for colorectal cancer

OBJECTIVE

The aim of this study was to determine whether anastomotic leakage has an independent association with overall survival and cancer-specific survival.

SUMMARY BACKGROUND DATA

There are many known prognostic indicators following surgery for colorectal cancer (CRC). However, the impact of anastomotic leakage has not been adequately assessed.

METHODS

Consecutive patients undergoing resection between 1971 and 1999 were recorded prospectively in the Concord Hospital CRC database. Total anastomotic leakage was defined as any leak, whether local, general, or radiologically diagnosed. Patients were followed until death or to December 31, 2002. The association between anastomotic leakage and both overall survival and cancer-specific survival was examined by proportional hazards regression with adjustment for other patient and tumor characteristics influencing survival. Confidence intervals (CI) were set at the 95% level.

RESULTS

From an initial 2980 patients, 1722 remained after exclusions. The total leak rate was 5.1% (CI 4.1-6.2%). In patients with a leak, the 5-year overall survival rate was 44.3% (CI 33.5-54.6%) compared to 64.0% (CI 61.5-66.3%) in those without leak. In proportional hazards regression-after adjustment for age, gender, urgent resection, site, size, stage, grade, venous invasion, apical node metastasis and serosal surface involvement-anastomotic leakage had an independent negative association with overall survival (hazard ratio [HR] 1.6, CI 1.2-2.0) and cancer-specific survival (HR 1.8, CI 1.2-2.6).

CONCLUSION

Apart from its immediate clinical consequences, anastomotic leakage also has an independent negative association with survival.

Anastomotic leakage after curative anterior resection results in a higher prevalence of local recurrence

BACKGROUND

The aim of this study was to determine whether leakage from a colorectal anastomosis following potentially curative anterior resection for rectal cancer is an independent risk factor for local recurrence.

METHODS

The study included all patients who had a potentially curative anterior resection with anastomosis for adenocarcinoma of the rectum between 1971 and 1991 at Concord Hospital. The data were collected prospectively, with complete follow-up for at least 5 years. The Kaplan-Meier method was used to compare time to recurrence between strata of categorical variables. Proportional hazards regression was used in multivariate modelling.

RESULTS

There were 403 patients in the study. After adjustment for lymph node metastases, the distal resection margin of resection, non-total anatomical dissection of the rectum and the level of anastomosis, multivariate analysis identified a significant association between anastomotic leakage and local recurrence (hazard ratio 3.8, 95 per cent confidence interval 1.8 to 7.9).

CONCLUSION

Leakage following a colorectal anastomosis after potentially curative resection for adenocarcinoma of the rectum is an independent predictor of local recurrence.

Locoregional recurrence in patients with anastomotic leakage after anterior resection for rectal carcinoma

OBJECTIVE

Anastomotic leakage is a serious complication after anterior resection for rectal carcinoma. It is controversial whether anastomotic leakage influences the rate of locoregional recurrence and therefore survival.

PATIENTS AND METHODS

The data of 940 patients with invasive rectal carcinoma stage I-III treated by curative anterior resection from 1978 to 1996 at the Department of Surgery of the University of Erlangen were analysed. Patients who received neoadjuvant or adjuvant treatment were excluded as well as patients who died postoperatively. 89 out of 814 patients (10.9%) developed an anastomotic leakage after anterior resection.

RESULTS

The rate of locoregional recurrence during the first five postoperative years of all patients was 13.6%. In patients with anastomotic leakage the rate of locoregional recurrence was 22.0%, significantly higher than in patients without anastomotic leakage which was 12.5%, (P=0.018). On multivariate Cox regression analysis anastomotic leakage was shown to be an independent risk factor for locoregional recurrence (relative risk: 1.7, CI 95%: 1.02-2.75, P=0.042). Also cancer-related survival was influenced significantly by anastomotic leakage in univariate analysis as well as in multivariate analysis (relative risk: 1.6, CI 95%: 1.1-2.2, P=0.017).

CONCLUSION

Anastomotic leakage after anterior resection for rectal carcinoma is a risk factor for locoregional recurrence and decreases cancer-related survival.

Rectal cancer recurrence: factors and mechanisms

OBJECTIVE

There have been significant developments in treatment for rectal carcinoma, both in surgical and adjuvant therapy. They may however have associated morbidity and hence individualized therapy for rectal cancer is desirable, to optimize treatment but avoid over-treatment for cases where the risk of recurrence is low.

MATERIALS AND METHODS

A literature review was undertaken of the reported incidence of recurrence of rectal carcinoma following curative surgery, factors which predispose to recurrence and proposed mechanisms for recurrence, and the evidence for each critically evaluated.

RESULTS

The incidence of local recurrence of rectal carcinoma following curative resection ranges from 2.6% to 32%, with an average of 15%. Tumour stage is the strongest predictor of tumour recurrence. Upstaging using molecular biology may predict increased risk of recurrence but is not yet proven. Histological factors including differentiation and vascular invasion increase recurrence but are imprecise. Tumour microvascular density and vascular endothelial growth factor (VEGF) levels may be predictive but need refinement. Adequate resection margins are important but recurrence may occur despite this. Tumour cell spillage and distant dissemination may be a mechanism for tumour recurrence following curative resection, but further research is required before this could be applied clinically.

CONCLUSION

Recurrence of rectal cancer remains a significant problem following 'curative' surgery. Multiple factors may influence recurrence risk, though currently however only tumour stage and histological resection margins have demonstrated sufficient importance for management decisions to be made upon them.

Is the port site really at risk? Biology, mechanisms and prevention: a critical view

Early case reports of port site tumour implants led to debate regarding the appropriateness of laparoscopic techniques for abdominal malignancies. Review of clinical, animal and cell culture studies addresses the relationships between tumour staging and shed cell behaviour that contributes to the peri-operative spread of tumours. In addition, a porcine model was used to test tumour cell distribution after laparoscopic and open colonic resections. Clinical evidence indicate that wound recurrence rates are 0.60 and 0.85% for open and laparoscopic colon cancer operations, respectively. Tumour staging and operative techniques are the most important factors determining wound implantation. Port site and open wounds are at equal risk of tumour implantation.

Peritoneal irrigation with povidone-iodine solution after laparoscopic-assisted splenectomy significantly decreases port-tumor recurrence in a murine model

PURPOSE

The development of port-wound tumor recurrences has raised questions regarding the safety of laparoscopic methods for the resection of malignancies. The cause and the incidence of abdominal-wall tumor recurrences remain unknown. It is also not clear how to avoid or lower the incidence of port-tumor recurrences. The purpose of the current study was to determine the impact of abdominal irrigation with povidone-iodine on the port-wound tumor incidence in a murine model.

METHODS

A splenic tumor model was used for this study. To establish splenic tumors, female BALB/c mice (N = 48) were given subcapsular splenic injections of a 0.1 ml suspension containing 10(5) C-26 colon adenocarcinoma cells via a left-flank incision at the initial procedure. Seven days later, the animals with isolated splenic tumors (100 percent) were randomly assigned to one of three groups: 1) control, 2) saline irrigation (saline), or 3) povidone-iodine irrigation. All animals underwent laparoscopic mobilization of the spleen using a three-port technique, intra-abdominal crushing of the tumor, followed by an extracorporeal splenectomy via a subcostal incision. No irrigation was performed for control group animals. In the saline irrigation group, the subcostal incision was closed and pneumoperitoneum was re-established. The abdominal cavity was irrigated with 5 ml of normal saline for 60 seconds before instrument removal. In the povidone-iodine irrigation group, similar abdominal irrigation was performed, using 0.25 percent povidone-iodine. Attempts were made to recover completely the irrigation for both irrigation groups. Seven days after the splenectomy, animals were killed and inspected for abdominal-wall tumor implants.

RESULTS

There were significantly more animals with at least one port-tumor recurrence in the control group than in the povidone-iodine group (P = 0.007). Although not statistically significant, the number of animals with port-wound tumors was higher in the saline group than in the povidone-iodine group (P < 0.08). There was no significant difference between the saline group and the control group. When each port site was considered independently, the incidence of port-wound tumors (number of ports with tumors per total number of ports) was significantly lower in the povidone-iodine group than in both the control (P = 0.00001) and saline groups (P = 0.03). The incidence of port-wound tumors was also significantly lower in the saline group compared with the control group incidence (P = 0.03).

CONCLUSIONS

Abdominal irrigation with dilute povidone-iodine solution significantly reduced the number of animals with port-tumor recurrences. Abdominal irrigation with saline was also effective in reducing the incidence of port-wound tumor formation when each port was considered separately. However, povidone-iodine irrigation was much more effective than saline irrigation in preventing port-wound tumor formation.

Model of implantation of tumor cells simulating recurrence in colonic anastomosis in mice

PURPOSE

Local recurrence after colorectal cancer surgery is usually perianastomotic. An experiment was designed to investigate whether free intraluminal cells can penetrate through a colonic anastomosis and thereby cause local recurrence.

METHODS

BALB/c and C57/BL mice underwent ascending colotomy followed by watertight anastomosis. Thereafter, CT-26 murine colon carcinoma cells were injected into the cecal lumen 2 cm proximal to the anastomosis of syngeneic BALB/c mice, whereas B-16 murine melanoma cells were injected in the same fashion into C57/BL mice. Control animals without anastomosis received similar injections. Animals were killed 24 hours, 72 hours, and 30 days after surgery and were checked for tumorigenesis.

RESULTS

Results of peritoneal fluid cytology were negative after 24 hours, whereas after 72 hours cancer cells were identified in the peritoneal fluid of 80 percent of mice with colotomy and anastomosis compared with 20 percent of control mice. Thirty days after surgery, 11.1 percent of the control BALB/c mice developed pericecal tumor growth, similar to the overall rate of murine melanoma in C57/BL. In mice with anastomoses, perianastomotic tumor growth was observed in 47.5 percent of BALB/c mice (P < 0.001) and was correlated with the number of injected cells. Tumor growth reached approximately 75 percent tumor take with high cell densities, whereas in C57/BL mice no difference was found between the experimental and control groups.

CONCLUSIONS

The findings suggest that free intraluminal cancer cells of colonic origin may penetrate through watertight anastomoses and implant on the anastomotic or peritoneal surface and initiate tumor growth. This anastomotic penetration is cell-mass dependent. The reported experimental model is simple, reproducible, and advantageous for studies of colonic anastomosis.

Rectal washout eliminates exfoliated malignant cells

PURPOSE

Irrigation of the rectal stump before anastomosis after resection for carcinoma is accepted colorectal surgical practice. However, not all surgeons perform this routinely, and it has never been established conclusively that irrigation of the rectal stump eliminates exfoliated malignant cells or even reduces local recurrence. The patients of a surgeon whose standard surgical practice involved rectal irrigation were compared with those of a surgeon who does not routinely practice rectal irrigation.

METHOD

Ten patients were given rectal washout with 200 to 500 ml of normal saline introduced via a Foley catheter per rectum. Ten patients were not given rectal washout. In both groups the anastomosis was performed with a circular stapler, and the stapler and donuts were rinsed in 200 ml of normal saline. The saline was sent for cytologic examination and classified as malignant cells seen or no malignant cells seen. The cytopathologist was blinded to the washout status.

RESULTS

Of the ten patients who had rectal washout performed, none had malignant cells seen. Of the ten patients who did not have rectal washout performed, eight had malignant cells seen in the cytology (P = 0.007; two-tailed Fisher's exact probability test).

CONCLUSION

Rectal washout eliminates exfoliated malignant cells in the rectum in the vicinity of the anastomosis.

Intraperitoneal exfoliated cancer cells in patients with colorectal cancer

PURPOSE

The aims of this study were to evaluate potential predictors of exfoliated free cancer cells in the peritoneal cavity and to assess intraoperative peritoneal lavage cytology as a prognostic indicator in patients with colorectal cancer.

METHODS

From 1985 to 1987, intraoperative peritoneal lavage cytology was performed in 140 patients with colorectal cancer. Among them, 88 patients underwent curative resection and 52 patients had noncurative surgery. Cytology was examined twice, i.e., immediately after opening the peritoneal cavity (precytology) and just before closing the abdomen (postcytology). One hundred milliliters of saline was poured into the peritoneal cavity and it was retrieved by suction after irrigation. Cytologic examination was performed after staining with Papanicolaou, Giemsa, periodic acid-Schiff, and Alcian blue stains.

RESULTS

Among the 140 patients examined, the incidence of positive cytology in the prelavage was 15 percent, and that in the postlavage was 9 percent, although it was 16 percent in either lavage. Among patients with curative resection, 10 percent had positive cytology. Seven characteristics were identified as features of tumors which are prone to exfoliate cells into the peritoneal cavity: 1) macroscopic peritoneal dissemination, 2) liver metastasis, 3) more than 20 ml of ascites, 4) ulcerated tumors without definite borders, 5) invasion of the serosal surface or beyond, 6) semiannular or annular shape, and 7) moderate or marked lymphatic invasion. In patients undergoing curative surgery, among these features, circumferential involvement was the only one correlated closely with positive cytology (P < 0.02). Positive cytology was associated with a worse outcome. In patients who were resected curatively, the postcytology had a stronger influence on local recurrence than the precytology; the local recurrence rate in patients with positive postcytology was higher than in those with negative postcytology, regardless of the precytology. All patients with cancer cells in the peritoneal cavity at the end of surgery had recurrence.

CONCLUSIONS

Seven characteristics were identified as risk factors for exfoliation of cancer cells into the peritoneal cavity in patients with colorectal cancer. These findings may be helpful for the choice of laparoscopic surgery in this era of increasing port-site metastases after laparoscopic procedure. The results of peritoneal lavage cytology at the end of surgery were correlated with the long-term postoperative outcome of colorectal cancer. Thus, meticulous follow-up and possibly adjuvant chemotherapy may be beneficial for patients with free cancer cells in lavage fluid, even after curative surgery.

Does laparoscopic vs. conventional surgery increase exfoliated cancer cells in the peritoneal cavity during resection of colorectal cancer?

PURPOSE

Traumatic manipulation of cancer specimens during laparoscopic colectomy may increase exfoliation of malignant cells into the peritoneal cavity, causing an early occurrence of peritoneal carcinomatosis or port-sites recurrence. Because of this concern, the routine use of intraperitoneal chemotherapy after laparoscopic colectomy for cancer was suggested recently. We assessed if laparoscopic vs. conventional surgery increases exfoliated malignant cells in the peritoneal cavity during resection of colorectal cancer.

METHODS

In a prospective, randomized fashion, 38 colorectal cancer patients undergoing an elective, curative operation were assigned to either a conventional or laparoscopic procedure between June 1996 and May 1997. In either group (n = 19), after the abdominal cavity was entered, saline was instilled into the peritoneal cavity, and the fluid was collected (Specimen 1). During surgery, all irrigating fluids were collected (Specimen 2). Both specimens were assessed for malignancy using four techniques: filtration process (ThinPrep), smear, cell block, and immunochemistry using Ber-EP4. The change in the amount of tumor cells in both specimens was compared between surgical groups. A pilot study was performed to validate the proposed cytologic method.

RESULTS

In the pilot study of 20 consecutive patients with colorectal cancer, postresectional peritoneal cytology was positive in six patients, including two Stage II (T3, N0, M0) patients. The pilot study also validated that our semiquantitative scoring system can be reliably used to assess the amount of free peritoneal cancer cells. In the main study, 16 right colectomies, 3 extended right colectomies, 17 proctosigmoidectomies, and 1 left colectomy were performed. The T and N stages were T1 (n = 13, T2 (n = 5), T3 (n = 8), T4 (n = 11); N0 (n =22), N1 (n = 8), N2 (n = 7). Malignant cells were not detected in any Specimens 1 or, more importantly, in Specimens 2 in either surgical group.

CONCLUSION

When performed according to strict oncologic surgical principles, laparoscopic techniques in curative colorectal cancer surgery did not have an increased risk of intraperitoneal cancer cell spillage, compared with conventional techniques. We hope that these results can decrease some of the concerns about tumor cell spillage and seeding during laparoscopy.

Bladder cancer recurrence by implantation of exfoliated cells: is gamma-linolenic acid an effective tumoricidal agent?

OBJECTIVE

To compare the tumoricidal efficacy of meglumine gamma-linolenic acid (MeGLA), mitomycin C, epirubicin and water on two urothelial cell lines, and to establish the effect of serum protein levels derived from bladder cancer resection craters on the action of these agents.

MATERIALS AND METHODS

The human urothelial cell lines MGHU-1 and RT112 and their drug-resistant variants were exposed to short pulses of aqueous MeGLA, mitomycin, epirubicin and water. Both adherent and suspended cells were exposed to these agents. The MTT viable biomass assay and a clonogenic assay were used to establish tumoricidal efficacy. These experiments were then repeated to assess the effect of added serum proteins on the test results. Estimates of protein in the waste irrigation fluid from 10 patients undergoing transurethral resection of bladder tumour (TURBT) were used to select the quantity of protein used in the study, to establish the clinical relevance.

RESULTS

MeGLA caused > 95% reduction in the residual viable biomass of adherent cells, compared with < 50% reduction with any other agent. Both epirubicin and mitomycin were as effective as MeGLA in preventing colony formation from suspended drug-sensitive (parental) cells. However, using multidrug-resistant (MDR) cell lines, only MeGLA prevented any colony formation, although counts were greatly reduced by mitomycin and epirubicin. Water was least effective as a tumoricidal agent on both adherent and suspended cells. On the latter, water was markedly inactivated by adding 5% serum. TURBT waste irrigation fluid was found frequently to contain such quantities of serous fluid contamination, as shown by albumin estimates in waste fluid from 10 consecutive patients undergoing this procedure.

CONCLUSION

MeGLA is an effective tumoricidal agent against both parental and MDR cell lines. Its efficacy is maintained in the presence of clinically relevant serum contamination.

Influence of blood components and faeces on the in vitro cancericidal activity of povidone-iodine

BACKGROUND

Tumoricidal agents have been used to kill viable exfoliated tumour cells following colorectal cancer surgery. Recent in vivo experiments have thrown some doubt on the tumoricidal activity of povidone-iodine.

METHODS

The cytotoxic effect of distilled water and of povidone-iodine at 0.04, 0.4, 0.8, 2 and 4 per cent final concentrations on human SW620 colonic cancer cells in the presence of red blood cells, purified haemoglobin and red blood cell (RBC) membranes, plasma, albumin, faeces and bacteria was investigated. Cell viability was assessed using the trypan blue assay and MTT test.

RESULTS

The presence of albumin and plasma decreased the tumoricidal activity of povidone-iodine except for the highest concentration tested. Bacterial suspension did not influence the efficacy of povidone-iodine. Faecal material was found to have an intrinsic tumoricidal effect. Both intact and lysed RBCs very strongly inhibited the tumoricidal activity of all povidone-iodine concentrations tested. This inhibitory effect was due to haemoglobin, but not to RBC membranes.

CONCLUSIONS

Low concentrations of povidone-iodine fail to kill all 'exfoliated' cancer cells in the presence of proteins, intact or lysed RBCs. Therefore, washing out of these organic materials before application of a relatively high povidone-iodine concentration (e.g. 5 per cent or greater) may be more useful in killing viable exfoliated tumour cells during surgery for colorectal cancer.

Incidence of free colorectal cancer cells on the peritoneal surface

BACKGROUND

The etiology and significance of port site recurrence occurring after laparoscopic-assisted resection for colorectal cancers will not be determined until controlled clinical trials determine if it is a predictor of outcome. Indirect evidence in support of transcoelomic spread of viable cancer cells to port sites during resection can be postulated by the presence of free cells on the fresh surface of colorectal specimens during primary resection.

PURPOSE

The study contained herein was undertaken to determine the incidence of free surface colorectal cancer cells by cytology during elective open resection and to correlate their presence with clinicopathologic variables.

METHODS

Fresh clamped and ligated consecutive colorectal cancer specimens were assessed in the operating room during primary resection for the presence of free colorectal cancer cells during an 18 month period at one institution. Clinicopathologic variables were assessed prospectively and blinded to cytology results. Interobserver reliability of cytologists was excellent (unweighted kappa, 0.93).

RESULTS

Overall, 15 of 103 (14.6 percent) colorectal cancers had positive cytology for cancer cells on the peritoneal or perirectal surface of the bowel. T3 and T4 tumors, the size or site of the tumor, lymph node status, mucinous characteristic, degree of differentiation, and the presence of vascular or neural invasion did not reach statistical significance as predictors of positive cytology in this study sample. The operative procedure performed was a statistically significant predictor of positive cytology. More than 50 percent of lymph nodes involved (28 percent), poorly differentiated tumors (28 percent), and the presence of liver metastases (22 percent) demonstrated a higher incidence of positive cytology, but this did not reach significant levels because of the limited power of the study sample for subgroup analysis.

DISCUSSION

The presence of free surface colorectal cancer cells gives only indirect support to the transcoelomic route to port site recurrence. The significance and true incidence will only be determined by prospective database analysis and randomized, controlled trials.

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

BACKGROUND

An increased risk of laparoscopic port wound tumor implantation in the presence of overt or covert abdominal malignancy has been identified.

PURPOSE

A porcine laparoscopic colectomy model has been used to quantify the influence surgical practices may have on tumor cell implantation.

METHODS

51Cr-labeled, fixed HeLa cells were injected intraperitoneally before surgery. Tumor cell contamination of instruments, ports, security threads, and excised wound margins was assessed by gamma counting.

RESULTS

Greatest contamination occurred in ports used by the operating surgeon under pneumoperitoneum (64 percent of all port wound tumor cells) and mechanical elevation (76 percent). Gasless surgery in patients in the head-down position increased the rostral accumulation of tumor cells in the abdomen and right upper quadrant port wound by 330 and 176 percent, respectively. Under pneumoperitoneum, port movement was the major contributor to port leakage and wound contamination (21 percent of total recovered wound tumor cells per port). Tumor cells were not carried in aerosol form. Instrument passage and the withdrawal of security threads through the abdominal wall increased port wound contamination 430 and 263 percent, respectively, over pneumoperitoneum control ports. Preoperative lavage reduced by 61 percent, but did not eliminate, wound contamination.

CONCLUSION

This porcine model may be used to evaluate surgical factors for the impact on port wound contamination.

Tumor cell distribution following laparoscopic colectomy in a porcine model

A clinically relevant, laparoscopic colectomy model has been developed to quantify surgical practices that may affect the incidence of port wound tumor implantation.

METHODS

Suspended 51Cr-labeled, fixed HeLa cells were injected intraperitoneally into pigs before laparoscopic colectomies were performed with or without insufflation. Tumor cell contamination of instruments, ports, stability threads, and excised port wound margins was determined by gamma counting.

RESULTS

Tumor cells were distributed throughout the peritoneal cavity, and the number detected at wound sites was directly related to number injected. Ports used by the operating surgeon had more cells than those used by the camera operator or assistant surgeon. Postoperative withdrawal of contaminated ports through abdominal wound was associated with an increase in port site contamination. Although the port site distribution of tumor cells was affected, mechanical elevation of abdominal wall did not eliminate contamination at any site.

CONCLUSION

These results demonstrate application of the porcine model to test current surgical practices and measures that might be used perioperatively to reduce the numbers of intraperitoneal tumor cells or their distribution to specific sites during laparoscopic or open surgery.

Exfoliated malignant cells in glove and instrument washings following head and neck surgery

Loco-regional recurrence following resection of squamous cell carcinoma of the upper aero-digestive tract is a major problem. Cells exfoliated from malignant tumours have been considered capable of implanting and giving rise to local recurrence or metastatic deposits. A prospective study was performed examining washings from the gloves and instruments used in major head and neck operations to determine if exfoliated cells were indeed present. Following removal of the main tumour specimen all surgeons washed their hands in a solution containing a cell fixative and all instruments were soaked in the solution. Samples were then centrifuged and stained using a modified PAP technique. On occasions nuclear fragments consistent with squamous cell carcinoma were present in both glove and instrument washings. We recommend that all surgeons change gloves and instruments following removal of the main tumour specimen and prior to irrigation of the operative field with a tumoricidal agent.

The exfoliation of free malignant cells in the peritoneal cavity during resection of colorectal cancer

The presence of free malignant cells in the peritoneal cavity following potentially curative resection of colorectal cancer may be responsible for some cases of local recurrence. Twenty-six patients (age 58-88 years, male:female 12:14) undergoing colorectal cancer surgery were studied to determine frequency of occurrence of tumour cells in the peritoneal cavity using an immuno-magnetic cell separation technique. Peritoneal washings were collected after opening the peritoneal cavity and also prior to closure. A murine monoclonal antibody specific for epithelial cells was added to the peritoneal washings followed by magnetic labelled goat-antimouse antibody. The labelled tumour cells were retrieved by passing through the magnetic activated cell sorter (MACS). Tumour cells were detected in peritoneal washings from 11 patients (preresection only n = 0, post-resection only n = 6, and both n = 5). Five of these 11 patients had potentially curative surgery. This study supports the use of MACS in detecting free malignant cells in the peritoneal cavity.

Colon-specific prodrugs of 5-radioiodo-2'-deoxyuridine

Two glycoside-based prodrugs, 125IUdR-5'-beta-D-glucopyranoside and 125IUdR-5'-beta-D-galactopyranoside, were synthesized. This selection was dictated by the abundance of appropriate enzymes in the GI tract of mice and similar levels of beta-D-glycosidases in human and rodent large intestine. Studies to establish the ability of colonic microflora to release 125IUdR were conducted in vitro and in Swiss Webster mice. Both prodrugs released 125IUdR in the presence of the corresponding enzymes or the GI content homogenates in vitro, and in vivo. Luminal enzymes in the proximal and distal small intestine in mice degraded less than 10% of each prodrug whereas enzymes from the colonic/caecal lumen of mice released nearly 100% of 125IUdR. 125IUdR freed by bacterial glycosidases was stable in the GI content. No significant amounts of other metabolites or deiodination products were observed. Total radioactivity recovered as by-products was less than 10%. The efflux of prodrugs from the GI tract after oral administration in mice was slow and limited. Unlike 125IUdR, prodrugs were not dehalogenated in vivo as indicated by biodistribution and imaging studies.

Efficacy of tumoricidal agents in vitro and in vivo

Implantation of exfoliated tumour cells can give rise to local recurrence of colorectal cancer and it has been recommended that the bowel lumen be lavaged with a tumoricidal agent. This study identified which tumoricidal agents are currently used in Scotland and investigated their efficacy in vitro and in vivo. Cytotoxic efficacy was tested in vitro by a clonogenic assay and in vivo by a rat model with viable intraluminal tumour cells. Overall 70 per cent of surgeons used a tumoricidal agent during colorectal cancer surgery. Povidone-iodine, sodium hypochlorite and chlorhexidine-cetrimide were all effective at killing tumour cells in vitro but were all inactivated by the presence of 25 per cent whole blood in vitro. With 10(5) cells in vivo povidone-iodine and sodium hypochlorite significantly (P < 0.02) reduced the incidence of tumour growth while chlorhexidine-cetrimide had no significant effect. With 10(6) cells povidone-iodine had no effect on the incidence of tumour growth. Tumoricidal agents have effective cytotoxicity in vitro but are only weakly cytotoxic in vivo.

Comparison of manually constructed and stapled anastomoses in colorectal surgery. West of Scotland and Highland Anastomosis Study Group

OBJECTIVE

The authors compared both the initial and the long-term outcomes of patients undergoing stapled and sutured colorectal anastomoses.

SUMMARY BACKGROUND DATA

Sutured and stapled large bowel anastomoses are perceived to be equally safe, but concern has been raised about increased rates of tumor recurrence with the use of stapling instruments.

METHODS

The outcome of patients with sutured and stapled colorectal anastomoses were compared in a prospective, multicenter, randomized study. Factors affecting long-term outcomes were assessed by both univariate and multivariate analysis.

RESULTS

Seven hundred thirty-two patients were recruited. There was a significant increase in radiologic leakage in the sutured group (14.4% vs. 5.2%, p < 0.05), but there was no difference in clinical anastomotic leak rates, morbidity, or postoperative mortality. Tumor recurrence and cancer-specific mortality were higher in the sutured patients (7.5% and 6.7%, respectively) and in patients with anastomotic leaks.

CONCLUSIONS

This study shows that suturing or stapling are equally safe in large bowel surgery. However, it also shows a long-term benefit of stapling in colorectal cancer patients.

Is there still a place for abdominoperineal resection of the rectum?

During the past two decades, low anterior resection (LAR) with colo-rectal or colo-anal anastomosis has replaced abdominoperineal resection (APR) as the primary surgical therapy for rectal cancer. Several studies, although not prospectively randomized, have shown that the outcome after LAR with deep anastomosis and APR is comparable concerning mortality, local recurrence rate and survival. Adequate clearance of the tumour, and not the surgical procedure performed, is the determinant factor influencing the outcome. Whereas most tumours in the upper third and mid-rectum are amenable to a sphincter-saving procedure (SSP), the lower third of the rectum is of debate in this respect. Small tumours (T1) in the lower third can be treated by peranal local excision. Low grade tumours with a T2 or T3 stage located above 3 cm from the dentate line are treated by SSP. There is still a place for for advanced tumours (T3 and T4) below 5 cm from the anal verge, in case of deficiency of the anal sphincter, and when the sphincter complex is infiltrated by the tumour. Preoperative staging measures are essential for patients selection in relation to height of the tumour above the anal canal, depth of tumour invasion into the rectal wall, and presence or absence of regional lymph node metastases. Biology of rectal cancer and its implication on surgery, preoperative staging of rectal cancer, technique and results of the main three surgical options, and the advent of laparoscopy are discussed in this article.

Detection of free malignant cells in the peritoneal cavity before and after resection of colorectal cancer

PURPOSE

This study was designed to select the best monoclonal antibody to stain malignant cells in peritoneal wash fluid, and to investigate the incidence of free malignant cells in preresection and postresection colorectal cancer peritoneal washings using a combination of conventional cytology and immunocytochemistry.

METHODS

Peritoneal washings were taken from 35 consecutive patients undergoing colorectal cancer resection.

RESULTS

Malignant cells were isolated on a density gradient and identified by conventional cytology and an indirect immunoperoxidase stain. Malignant cells were identified in peritoneal washings from 15 patients (preresection only n = 3, postresection only n = 4, both n = 8). The origin of free malignant peritoneal cells in 11 preresection-positive washings must be the serosa. The origin of these cells in the four postresection-positive patients is uncertain: serosal and luminal spillage were considered unlikely and no circulating cells were found in the mesenteric vessels near the tumor.

CONCLUSION

Tumor cells may have leaked out from lymphatics cut during the dissection.

Serosal imprint cytology in colonic cancer: a simple staging technique

Accurate staging of colonic cancer is essential in defining the rational use of adjuvant treatments. Recent studies have shown that prognostic accuracy can be significantly improved by recognition of primary tumour extension to the free serosal surface. This study compares the technical results of serosal imprint cytology with the results of histology in assessing serosal involvement. When analysed in terms of the modified Dukes' staging the results of cytology imprints taken from the peritoneum overlying the colonic primary were positive for tumour cells in 4/13 Dukes' B, 7/14 Dukes' C, and 5/9 metastatic cancers. Imprint cytology was positive in 6/7 Dukes' B and C cases with histological serosal invasion and was suspicious in the remaining case. However, a further 5/20 cases without identified invasion on routine histology also had positive cytology. Imprint cytology is an adjunct to routine histology which is easily performed and allows more precise staging of serosal involvement in Dukes' B and C colonic cancers. Final evaluation of this technique requires long-term follow-up of patients.

Local recurrence of colorectal cancer: the problem, mechanisms, management and adjuvant therapy

Local recurrence of colorectal cancer after 'curative' surgery is a major clinical problem. Typically, 50-70 per cent of patients presenting to a surgical clinic will undergo apparently curative surgery for disease and of these about 10-25 per cent will develop local recurrence, in either the tumour bed or bowel wall. The wide differences in local recurrence rate both between and within institutions is probably caused by variation in surgical technique. The main causes of local recurrence are inadequate excision of the primary tumour or the draining lymph nodes, and intraoperative tumour cell implantation. The most significant single factor prognostic of local recurrence is Dukes' tumour stage. Other important factors include tumour grade and fixity, level of the tumour in the rectum, blood and lymphatic vessel invasion, inadvertent perforation of the tumour during resection, and the surgeon's experience. The prognosis of patients with local recurrence is poor. Prevention of recurrence by adequate surgery and adjuvant therapy as well as its early detection offer the best prospect of improving results.

Sphincter-saving alternatives for treatment of adenocarcinoma involving distal rectum

In reviewing the results achieved with local treatment of carcinoma of the rectum, it becomes apparent that no single approach to the treatment of carcinoma of the rectum is optimal for all patients. As is true in patients with carcinoma of the breast and other malignant lesions, selection of the appropriate treatment alternatives for a patient with carcinoma confined to the distal rectum requires accurate preoperative staging of the disease. Physicians interested in treating patients with carcinoma of the rectum should have the full spectrum of treatment alternatives available.

Principles of surgical resection. Influence of surgical technique on treatment outcome

In the absence of curative medical therapy, surgical resection remains the cornerstone of treatment for patients with colorectal carcinoma. A thorough knowledge of colon and rectal anatomy is crucial for the formulation of an effective operative strategy. There are certain technical factors under the control of the surgeon that may have prognostic significance for the patient. These include the length of the distal margin of resection, the use of intraluminal cytotoxic solutions to reduce the viability of exfoliated cancer cells, and the technique of colon anastomosis. Curative resections should include removal of the lymphatic drainage of the tumor-bearing segment of colon. When there is adjacent organ invasion by the colonic primary, en block resection of the entire tumor mass with adequate margins is the procedure of choice. Prophylactic oophorectomy in women with colon carcinoma remains controversial. The effects of perioperative transfusion on tumor behavior remain unclear. Blood transfusions should be administered only when there is a specific medical necessity.

Malignant cells are collected on circular staplers

Anastomotic recurrence after resection of colorectal carcinoma has been attributed to insufficient clearance, migration of tumor cells into lymphatics, or implantation of exfoliated malignant cells during anastomosis. We studied 10 patients submitting to low anterior resection for cancer 6 to 16 cm (mean, 12.6 cm) from the anal verge. The anastomosis was performed with a circular stapler introduced transanally into the rectum using the established technique. No lavage of the rectal stump with a cytotoxic agent was conducted before the anastomosis was performed. Having completed the anastomosis, the stapler and the doughnuts were washed with saline, which was collected for cytologic examination. The doughnuts were then examined histologically; all were tumor free. In 9 of the 10 cases, malignant cells were identified in the centrifuged saline. It may be that malignant cells collected by the stapler are implanted during anastomosis and cause subsequent anastomotic recurrence.