Failure to complete adjuvant chemotherapy is associated with adverse survival in stage III colon cancer patients.

Two recent North American studies have shown that completion of 5-fluorouracil (5FU)-based adjuvant chemotherapy is a major prognostic factor for the survival of elderly stage III colon cancer patients. The aim of the present study was to confirm this finding in a population-based series from Australia. The study cohort comprised 851 stage III colon cancer patients treated by surgery alone and 461 who initiated the Mayo chemotherapy regime. One-third of patients who initiated chemotherapy failed to complete more than three cycles of treatment. Independent predictors for failure to complete were treatment in district or rural hospitals, low socioeconomic index and treatment by a low-volume surgeon. Patients who failed to complete chemotherapy showed worse cancer-specific survival compared not only to those who completed treatment (HR=2.24; 95% confidence interval (CI) (1.66-3.03), P<0.001) but also to those treated by surgery alone (HR=1.37; 95% CI (1.09-1.72), P=0.008). The current and previous studies demonstrate the importance of completing adjuvant 5-FU-based chemotherapy for colon cancer. Further prospective studies are required to identify better the physiological and socioeconomic factors responsible for failure to complete chemotherapy so that appropriate improvements in health service delivery can be made.

Randomized clinical trial of bowel preparation with a single phosphate enema or polyethylene glycol before elective colorectal surgery.

BACKGROUND: A recent meta-analysis has questioned the value of bowel preparation in patients undergoing colorectal resection. The aim of this clinical trial was to evaluate whether a single phosphate enema was as effective as oral polyethylene glycol (PEG) solution in preventing anastomotic leakage. METHODS: Patients were randomized to receive either a single phosphate enema or 3 litres of oral PEG solution before surgery. Patients were followed for a minimum of 6 weeks to detect anastomotic leakage. RESULTS: There were 147 patients in each group and the groups were evenly matched for putative risk factors at baseline. Patients in the enema group had more anastomotic leaks requiring reoperation than those in the PEG group (4.1 versus 0 per cent, P = 0.013; relative risk 2.04 (95 per cent confidence interval (c.i.) 1.82 to 2.30)). The mortality rate was higher in the PEG group (2.7 versus 0.7 per cent, P = 0.176; odds ratio 1.62 (95 per cent c.i. 0.45 to 36.98)). CONCLUSION: Bowel preparation with a phosphate enema was associated with an increased risk of anastomotic leakage requiring reoperation compared with oral PEG. These results do not support the routine use of a phosphate enema in patients undergoing elective colorectal surgery.

Branched-chain amino acids.

The branched-chain amino acids (BCAA), isoleucine, leucine and valine, are unique in that they are principally metabolized extrahepatically in the skeletal muscle. This observation led to the investigation of these nutrients in a number of clinical scenarios. By far the most intensively studied applications for BCAA have been in patients with liver failure and/or patients in catabolic disease states. However, the resulting studies have not demonstrated a clear clinical benefit for BCAA nutritional supplements. In patients with liver failure, the BCAA did improve nitrogen retention and protein synthesis, but their effect on patient outcome was less clear. Similarly, in critically ill septic patients, BCAA did not improve either survival or morbidity. The BCAA are important nutrients, and it seems that any specific benefits associated with their use will be based upon a greater understanding of the underlying cellular biology. Potential areas of further research may include the combination of BCAA supplements with other anabolic factors (e.g. growth hormone) in managing patients with catabolic disease states.

What is the role of mechanical bowel preparation in patients undergoing colorectal surgery?

BACKGROUND: Most surgeons use mechanical bowel preparation before performing operations on the colon and rectum. The aim of this study is to determine if there is any published literature that supports this practice. METHODS: We undertook a review of the literature on the benefits of mechanical bowel preparation in patients undergoing surgery on the colon and rectum. A meta-analysis was conducted on all available clinical trials addressing this issue. RESULTS: A meta-analysis of three clinical trials revealed a significantly greater incidence of wound infection in patients who received a mechanical bowel preparation (10.8 vs. 7.4 percent; P < 0.002; 95 percent confidence interval of the difference, -1.6-8.4 percent). Patients who received mechanical bowel preparation had an incidence of anastomotic leakage that was twice that of control patients; however, this difference was not significant (8.1 vs. 4 percent; P < 0. 1 14; 95 percent confidence interval of the difference, -0.4-8.4 percent). CONCLUSION: There is limited evidence in the literature to support the use of mechanical bowel preparation in patients undergoing colorectal surgery. Hence, there is a need for clinical trials comparing the more traditional, aggressive forms of bowel preparation (e.g., polyethylene glycol solutions, sodium phosphate) with either no preparation or simpler techniques, such as a single phosphate enema.

The influence of branched chain amino acids on colonic atrophy and anastomotic strength in the rat.

Conventional solutions of parenteral nutrients fail to reverse the colonic atrophy caused by starvation. This may be due to the absence from these solutions of the amino acid glutamine--a fuel for rapidly dividing cells such as colonocytes and fibroblasts. Although glutamine is unstable in solution, the infusion of branched chain amino acids (BCAA) increases the rate of synthesis and release of glutamine from skeletal muscle. We evaluated the hypothesis that the infusion of BCAA into undernourished rats would reduce the extent of mucosal atrophy and enhance the healing of anastomoses in the colon. Undernourished rats were randomized to receive 6 days of either a normal diet (Chow), conventional parenteral nutrition (CPN), or CPN supplemented with 1.8% BCAA (BCAA). The BCAA group had a higher plasma glutamine concentration than the Chow group (P less than 0.05). Compared with the CPN group, the BCAA group had the greater colonic mucosal weight (P less than 0.05) and colonic mucosal protein content (P less than 0.05), but there were no significant differences between groups in the bursting wall tension of the colon or the hydroxyproline content of the anastomoses. Although the infusion of BCAA has a beneficial effect on colonic atrophy, this did not result in the more secure healing of colonic anastomoses in this experimental model.