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

Systematic review and meta-analysis of intraoperative peritoneal lavage for colorectal cancer staging

BACKGROUND

Intraperitoneal cancer cells are detectable at the time of colorectal cancer resection in some patients. The significance of this, particularly in patients with no other adverse prognostic features, is poorly defined. Consequently peritoneal lavage is not part of routine practice during colorectal cancer resection, in contrast with other abdominal malignancies. The aim of this systematic review was to determine the effect of positive intraoperative peritoneal cytology on cancer-specific outcomes in colorectal cancer.

METHODS

A systematic review of key electronic journal databases was undertaken using the search terms 'peritoneal cytology' and 'colorectal' from 1980 to 2012. Studies including patients with frank peritoneal metastasis were excluded. Meta-analysis for overall survival, local/peritoneal recurrence and overall recurrence was performed.

RESULTS

Twelve cohort studies (2580 patients) met the inclusion criteria. The weighted mean yield was 11·6 (range 2·2-41) per cent. Yield rates were dependent on timing of sampling (before resection, 11·8 per cent; after resection, 13·2 per cent) and detection methods used (cytopathology, 8·4 per cent; immunocytochemistry, 28·3 per cent; polymerase chain reaction, 14·5 per cent). Meta-analysis showed that positive peritoneal lavage predicted worse overall survival (odds ratio (OR) 4·26, 95 per cent confidence interval 2·86 to 6·36; P < 0·001), local/peritoneal recurrence (OR 6·57, 2·30 to 18·79; P < 0·001) and overall recurrence (OR 4·02, 2·24 to 7·22; P < 0·001).

CONCLUSION

Evidence of intraoperative peritoneal tumour cells at colorectal cancer resection is predictive of adverse cancer outcomes.

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.

CT detection of hydronephrosis in resected colorectal cancer: a predictor of recurrent disease

AIM

To investigate the causes and significance of hydronephrosis in follow-up of colorectal cancer.

METHODS AND MATERIALS

Case notes and serial computed tomography (CT) examinations were reviewed of 75 patients (250 CT examinations) after resection for colorectal cancer in whom hydronephrosis developed on follow-up.

RESULTS

The most common cause of hydronephrosis was a focal plaque-like mass centred on the peritoneum, demonstrated in 37 cases (49%). Patients with R1 (microscopic residual tumour) or R2 (macroscopic residual tumour) disease developed hydronephrosis at a median time of 13 months (90% CI: 9-18 months) compared with 22 months (90% CI: 17-26 months) for those having (R0) curative resection. Patients with pT4 invasion of peritoneum or adjacent organs developed hydronephrosis at a median of 14 months (90% CI: 6-16 months) compared with a median of 22 months in patients with pT3 tumours (90% CI: 11-27 months). Of 26 patients without an obvious cause of hydronephrosis on initial CT examination, follow-up CT demonstrated a definite mass lesion in 50%. Median survival after the onset of hydronephrosis was 6 months (range 1-34 months) with a 1-year mortality of 62%.

CONCLUSIONS

Hydronephrosis is an important early indicator of colorectal cancer recurrence, even in the absence of a mass.

[Evaluation of povidone abdominal washing for prevention of peritoneal cancer cell seeding: experimental study in the rat]

GOAL

The aim of the study was to evaluate the in vitro cytototoxicity of diluted povidone iodine on colon cancer cells and its in vivo antitumoral effect in a model of peritoneal carcinomatosis in the rat.

METHODS

Cell cytotoxicity of a povidone iodine diluted solution was assessed, in vitro, on rat colon cancer cells (DHD/K12/PROb) and human colon cancer cells (HT29). The antitumoral effect of diluted povidone iodine washing was measured in BDIX rats after the intraperitoneal inoculation of 10(6) DHD/K12/PROb cells. Results were compared to an abdominal washing within a 9 g/l salinel solution. In one experiment, peritoneal scars and a colocolic anastomosis were performed after the injection of cancer cells.

RESULTS

A short 10 min incubation of human and rat colon cancer cells with diluted povidone iodine resulted in a complete cell killing. In animals, a peritoneal washing with 1% diluted povidone iodine completely inhibited the tumor growth in parietal peritoneum. However, development of peritoneal tumor nodules was not inhibited in the omentum, in scarified peritoneum or in intestinal anastomosis.

CONCLUSIONS

Despite its high in vitro efficacy, diluted povidone iodine has an incomplete effect in the prevention of peritoneal carcinomatosis, with only a partial inhibition in scarred peritoneum epiploïc area and intestinal anastomosis. In contrary, it procures a complete inhibition of tumor growth in normal peritoneum.

Limitations of peritoneal lavage with antiseptics in prevention of recurrent colorectal cancer caused by tumor-cell seeding: experimental study in rats

PURPOSE

Exfoliated or soiled free malignant cells have serious consequences in patients undergoing gastrointestinal cancer surgery. The present study evaluates the toxicity and efficacy of cytotoxic agents in the prevention of cell seeding and tumor growth in the peritoneal cavity in an experimental model.

METHODS

Mtln3 adenocarcinoma cell viability was tested in vitro using the trypan blue exclusion test after incubation with povidone-iodine or chlorhexidine. In vivo, Fischer rats were inoculated with 10(5) or 10(6) cells followed by peritoneal lavage with physiological saline, chlorhexidine 0.02 percent, povidone-iodine low molecular weight 1 percent or povidone-iodine high molecular weight 1 and 2 percent in different quantities and incubation times.

RESULTS

Chlorhexidine 0.02 percent and povidone-iodine low molecular weight 1 percent or high molecular weight 2 percent, killed over 98 percent of 10(5) or 10(6) tumor cells in vitro. Povidone-iodine low molecular weight 1 percent and high molecular weight 2 percent were toxic and lethal when 5 ml were applied in the peritoneal cavity three times for five minutes. Chlorhexidine 0.02 percent applied after inoculation of 10(5) or 10(6) cells, reduced the tumor development only to 70 and 80 percent. Application of 5 ml povidone-iodine 1 percent low molecular weight or high molecular weight, three times for one and five minutes, after inoculation of 10(6) cells did not change the tumor take. However, inhibition of Mtln3 cells to form metastases was observed. When povidone-iodine low molecular weight 1 percent was used three times for one minute after 10(5) tumor cells were "soiled", no toxicity was observed and the tumor take was reduced to 30 percent (P < 0.05).

CONCLUSIONS

Povidone-iodine toxicity proved to be a major issue in vivo. However, povidone-iodine low molecular weight 1 percent was safe when used for short periods and very effective when a limited number of tumor cells was inoculated. The use of cytotoxic agents to prevent recurrent disease caused by tumor cell seeding in patients seems to make sense only when the "inoculum size" of exfoliated or soiled cancer cells is limited.

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.