Incidence and prognosis of lower rectal cancer with limited extramesorectal lymph node metastasis.

Abstract

Patients with lower rectal cancer occasionally have limited extramesorectal lymph node metastasis. However, the incidence and prognosis of lower rectal cancer with limited extramesorectal lymph node metastasis remain unclear. A total of 714 patients with clinical stage II or III lower rectal cancer who underwent extramesorectal lymph node dissection at the National Cancer Center Hospital between 1985 and 2011 were reviewed. Among the 714 patients with lower rectal cancer, 35 (4.9%) had limited extramesorectal lymph node metastasis, of whom 28 (80.0%) had one or two extramesorectal lymph node metastases. The 5-year overall survival rate was 74.5%. The number of extramesorectal lymph node metastases was a significant prognostic factor. The 5-year overall survival rate of patients with three or more extramesorectal lymph node metastases was 28.6%. The incidence of limited extramesorectal lymph node metastasis in patients with lower rectal cancer was 4.9%. Although the prognosis of patients with one or two extramesorectal lymph node metastases was favorable, that of patients with three or more such metastases was unfavorable.