Rectum versus colon: should malignant polyps be treated differently?

BACKGROUND: The management of malignant colorectal polyps removed at endoscopy remains controversial with patients either undergoing surgical resection or regular endoscopic surveillance. Lymph node (LN) metastases occur in 6-16% of patients with malignant polyps. This study assessed the rate of LN metastases in patients undergoing surgical resection for malignant polyps removed endoscopically to determine if there is a difference in the rate of LN metastases between colonic and rectal polyps. METHODS: A retrospective review of a prospectively maintained database was performed from 2010 to 2018. All patients who underwent surgical resection following endoscopic removal of a malignant colorectal polyp were reviewed. Clinical data including patient demographics and tumour characteristics were examined. RESULTS: A total of 177 patients underwent surgical resection in the study period. The median age at diagnosis was 65 years (range 22-88 years) with females comprising 52% of the patient cohort (n = 92/177). Polyps were located in the colon in 60.5% of cases with the remainder located in the rectum. The median number of LN harvested was 14 (range 0-44) with malignant LN (including a mesenteric tumour deposit) identified in 8.5% of resection specimens (n = 15/177). Malignant LNs were retrieved in 5.5% of right-sided tumours, 5.6% of left-sided tumours and 12.9% of rectal tumours (P = 0.090). CONCLUSION: A small proportion of patients with malignant polyps removed endoscopically will have LN metastases. The results of this study suggest that the tumour location might be a useful predictive marker; however, a further study with increased patient numbers is required to properly establish this finding.

Meta-analysis of the clinicopathological characteristics and peri-operative outcomes of colorectal cancer in obese patients.

BACKGROUND: The effect of obesity on the clinicopathological characteristics of colorectal cancer (CRC) has not been clearly characterized. This meta-analysis assesses the pathological and perioperative outcomes of obese patients undergoing surgical resection for CRC. METHODS: Meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Databases were searched for studies reporting outcomes for obese and non-obese patients undergoing primary CRC resection, based on body-mass index measurement. Results were reported as mean differences or pooled odds ratios (OR) with 95% confidence intervals (95% CI). RESULTS: A total of 2183 citations were reviewed; 29 studies comprising 56,293 patients were ultimately included in the analysis, with an obesity rate of 19.3%. Obese patients with colorectal cancer were more often female (OR 1.2, 95% CI 1.1-1.2, p<0.001) but there was no difference in the proportion of rectal cancers, T4 tumours, tumour differentiation or margin positivity. Obese patients were significantly more likely to have lymph node metastases (OR 1.2, 95% CI 1.1-1.2, p<0.001), have a lower nodal yield, were associated with a longer duration of surgery, more blood loss and conversions to open surgery (OR 2.6, 95% CI 1.6-4.0, p<0.001) but with no difference in length of stay or post-operative mortality. CONCLUSION: This meta-analysis demonstrates that obese patients undergoing resection for CRC are more likely to have node positive disease, longer surgery and higher failure rates of minimally invasive approaches. The challenges of colorectal cancer resection in obese patients are emphasized.