Analysis of indication for extended lymphadenectomy with lateral lymph node dissection for rectal cancer

[Aims] This study aimed to clarify the appropriateness of our indications and the significance of extended lymphadenectomy with lateral lymph node dissection in rectal cancer patients. [Methods] A total of 119 patients with lower rectal cancer underwent curative surgery in our hospital between 1981 and 1998 were selected. The relationship between their outcome and clinicopathological features was analyzed by retrospective study. [Results] The patients fell into two groups : 60 patients who underwent lateral lymph node dissection (dissection group) and 59 who underwent conventional resection without lateral lymph node dissection (control group). The histological stage was less progressive and a 5-year survival rate was higher in the dissection group than in the control group. Multivariate analysis revealed that there was no significant correlation between lateral lymph node dissection and the outcome. The incidence of local recurrence was low in both groups (dissection group : 11.7% (7/60) ; control group : 1.7% (1/59)), however, there was no significant difference between the two groups. The patients with lateral lymph node metastasis had a high incidence (90.0% : 9/10) of recurrence, including hematogenous metastasis, and an extremely low 5-year survival rate (13.1%). [Conclusions] In view of local recurrence, our current indications for lateral lymph node dissection seem to be appropriate. Since lateral lymph node dissection had a preventive effect against local recurrence, but did not improve the outcome of the patients with lateral lymph node metastasis, it may be necessary to consider function-preserving surgery combined with extensive adjuvant-therapy.