Practice parameters for the management of colonic cancer I: surgical issues. Recommendations of the Colorectal Surgical Society of Australia

Pre-operative mechanical bowel cleansing or not? an updated meta-analysis

OBJECTIVES

Pre-operative mechanical bowel preparation has been considered an efficient regimen against leakage and infectious complications, after colorectal resections. This dogma is based only on observational data and experts' opinions. The aim of this study was to evaluate the efficacy and safety of prophylactic pre-operative mechanical bowel preparation before elective colorectal surgery.

METHODS

EMBASE, LILACS, MEDLINE and The Cochrane Library and abstracts from major gastroenterological congresses were searched. No language restrictions were applied. The selection criterion used was randomised clinical trials (RCT) comparing any kind of mechanical bowel preparation with no preparation in patients submitted to elective colorectal surgery and where anastomotic leakage, mortality, and wound infection were outcome measurements. Data were independently extracted by the reviewers and cross-checked. The methodological quality of each trial was assessed by the same reviewers. For meta-analysis the Peto-Odds ratio was used.

RESULTS

Of 1592 patients (9 RCTs), 789 were allocated to mechanical bowel preparation (Group A) and 803 to no preparation (Group B) before elective colorectal surgery. Anastomotic leakage developed in 48 (6%) of 772 patients in A compared with 25 (3.2%) of 777 patients in B; Peto OR 2.03, 95% (CI: 1.28-3.26; P = 0.003). Wound infection occurred in 59 (7.4%) of 791 patients in A and in 43 (5.4%) of 803 patients in B; Peto OR 1.46, 95% (CI: 0.97-2.18; P = 0.07); Five (1%) of 509 patients died in group in A compared with 3 (0.61%) of 516 patients in group B; Peto OR 1.72, 95% (CI: 0.43-6.95; nonsignificant).

CONCLUSION

There is no evidence that patients benefit from mechanical bowel preparation. On the contrary taking colorectal surgery as a whole, pre-operative bowel cleansing leads to a higher rate of anastomotic leakage. The dogma that mechanical bowel preparation is necessary before elective colorectal surgery has to be reconsidered.

Mechanical bowel preparation for elective colorectal surgery

BACKGROUND

For over a century the presence of bowel content during surgery has been linked to anastomotic leakage. Mechanical bowel preparation has been considered an efficient agent against leakage and infectious complications. This dogma is not based on solid evidence, but on observational data and expert's opinions.

OBJECTIVES

To determine the effectiveness and safety of prophylactic mechanical bowel preparation for morbidity and mortality rates in elective colorectal surgery.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, LILACS, and the Cochrane Central Register of Controlled Trials. We also searched relevant medical journals, and conference proceedings from major gastroenterological congresses and contacted experts in the field. We used the search strategy described by the Colorectal Cancer Review Group, without limitations for date of publication and language. I SELECTION CRITERIA: Randomised, clinical trials that compared any strategy in mechanical bowel preparation with no mechanical bowel preparation.

DATA COLLECTION AND ANALYSIS

Data were independently extracted by the reviewers and cross-checked. The same reviewers assessed the methodological quality of each trial. Details of the randomisation (generation and concealment), blinding, whether an intention-to-treat analysis was done, and the number of patients lost to follow-up was recorded. For analysis the Peto odds ratio (OR) was used as defaults.

MAIN RESULTS

Of the 1592 patients (9 trials), 789 were allocated to mechanical bowel preparation (Group A) and 803 to no preparation (Group B) before elective colorectal surgery. For anastomotic leakage (main outcome) the results were: - Low anterior resection: 9.8% (11 of 112 patients in Group A) compared with 7.5% (9 of 119 patients in Group B); Peto OR 1.45, 95% confidence interval (CI): 0.57 to 3.67 (non-significant); - Colonic surgery: 2.9% (Group A) compared with 1.6% (Group B) ; Peto OR 1.80, 95% CI: 0.68 to 4.75 (non-significant); Overall anastomotic leakage: 6.2% (Group A) compared with 3.2% (Group B); Peto OR 2.03, 95% CI: 1.276 to 3.26 (p=0.003). For the secondary outcome of wound infection the result was: 7.4% (Group A) compared with 5.4% (Group B); Peto OR 1.46, 95% CI: 0.97 - to 2.18 (p=0.07); Sensitivity analyses excluding studies with dubious randomisation, studies published as abstracts only, and studies involving children did not change the overall conclusions

AUTHORS' CONCLUSIONS

There is no convincing evidence that mechanical bowel preparation is associated with reduced rates of anastomotic leakage after elective colorectal surgery. On the contrary, there is evidence that this intervention may be associated with an increased rate of anastomotic leakage and wound complications. It is not possible to be conclusion on the latter issue because of the clinical heterogeneity of trial inclusion criteria, methodological inadequacies in trial (in particular, poor reporting of concealment and allocation), potential performance biases, and failure of intention-to-treat analyses. Nevertheless, the dogma that mechanical bowel preparation is necessary before elective colorectal surgery should be reconsidered.

Surgeon influenced variables in resectional rectal cancer surgery

PURPOSE

Surgeon influenced variables in rectal cancer surgery were assessed.

METHODS

The literature was reviewed to discuss technical and educational issues that may affect the outcome of surgery for rectal cancer. Particular attention was paid to recently debated topics such as adjuvant therapy, colonic J-pouches, total mesorectal excision, and surgeons' training.

RESULTS

In some selected cases, transanal techniques with or without neoadjuvant or adjuvant therapy have improved the success of local excision. The biology of rectal cancer has begun to be understood. However, until a more complete understanding with an appreciation of therapeutic implications has been arrived at, surgeon influenced variables will continue to be of paramount importance. Multiple studies have shown tremendous surgeon variability in the outcome after rectal cancer surgery. Some of the variables that have been shown to be important include tumor-free distal and lateral margins, a total mesorectal excision, and an appropriate anastomosis. It has been well demonstrated that proctectomy with straight coloanal anastomosis compromises function as compared with preoperative levels or healthy controls. These deficiencies are further exacerbated by adjuvant therapy. Significant functional improvements, particularly in the first 12 to 24 months after surgery, have been achieved with use of colonic J-pouch.

CONCLUSION

There are many ways by which the surgeon can optimize curative resection for rectal cancer. Appropriate distal and tumor-free lateral margins with total mesorectal excision should be the goals for all tumors in the lower two-thirds of the rectum. Reconstruction should be performed, whenever technically possible, by a colonic J-pouch. Surgeons should be cognizant of their own practice patterns, volume, capabilities, and very importantly results. These results should be audited frequently and willingly shared with patients.