Location of rectal cancer within the circumference of the rectum does not influence lymph node status.

BACKGROUND

Patients with rectal cancer are treated in multimodal concepts on the basis of their tumor stage. In the context of local excision, it is of major importance to assess the risk of lymph node metastases in patients with T1 or T2 tumors. To identify patients with an increased risk of lymph node metastases, the influence of the location of the tumor within the rectum (anterior, posterior, lateral) and of other variables on lymph node status was investigated.

METHODS

All consecutive patients undergoing low anterior resection or abdominoperineal resection for primary rectal cancer between October 2001 and September 2003 were included. A multivariate analysis was performed focussing on tumor location and other variables as potential predictive factors for lymph node metastases.

RESULTS

Of 148 included patients, 135 (91%) had an anterior and 13 (9%) an abdominoperineal resection. All patients routinely underwent total mesorectal excision. A statistically significant correlation with positive lymph node status was found for patients with lymphatic invasion (P < .0001), higher T stage (P < .0001), presence of distant metastases (M1) (P = .0003), and circular growth of the tumor (P = .003), but not for tumor location. Multivariate analysis confirmed that patients without lymphatic invasion (odds ratio, .1; 95% confidence interval, .02-.48; P = .006) and with a low T stage (odds ratio, .07; 95% confidence interval, .002-.9; P = .004) have a significantly lower risk for positive lymph nodes.

CONCLUSIONS

Location of rectal cancer (anterior, posterior, lateral) is not a good predictor for lymph node metastases.