OBJECTIVETo study the relationship between the degree of mesorectal tumor invasion and prognosis of the patients with middle-low rectal cancer.

METHODSSpecimens from 49 patients with middle-low rectal cancer, undergone total mesorectal excision in our hospital from April 2003 to December 2003,were studied by large slice pathologic technique. The thickness of mesorectum and the depth of tumor infiltration were measured, and the degree of mesorectal tumor invasion was calculated. The local recurrence rate, metastasis rate and 5-year survival rate were investigated respectively. Possible clinicopathological influence factors were also analyzed.

RESULTSThe local recurrence rate was 12.2%(6/49), the distant metastasis rate was 26.5%(13/49). In three different degrees of mesorectal tumor invasion(I(,II(,III(), the local recurrence rates were 0, 7.7% and 31.3% (chi(2)=7.357, P =0.015); the metastasis rates were 10%, 23.1% and 50%(chi(2)=7.405, P =0.025); the 5-year survival rates were 90.9%, 69.2% and 28.6%(log-rank, P =0.013). Tumor diameter, T and N staging were risk factors influencing the degree of mesorectal tumor invasion(chi(2)=6.849 P=0.033, chi(2)=34.845 P =0.000, chi(2)=17.266 P =0.002).

CONCLUSIONSThe degree of mesorectal tumor invasion is an important predictor of local and distant metastasis as well as survival of patients in middle-low rectal carcinoma. The degree of mesorectal tumor invasion in the middle-low rectal carcinoma is significantly correlated with tumor diameter, T and N stage.