Background and purpose:The extent of lymph node dissection for the stageⅢ lower rectal cancer is still a subject of debate. Some Japanese researchers recommend improved lateral lymph node dissection for stageⅢ lower rectal cancers while American scholars claim that total mesorectal excision is sufficient. This study aimed to explore the clinical significance of improved lateral lymph node dissection for stageⅢ lower rectal cancer in patients treated with radical resection.Methods:Sixty-six patients with stageⅢ lower rectal cancer were enrolled. Among these patients, 31 had been treated with radical resection combined with improved lateral lymph node dissection, whereas the others received radical resection without improved lateral lymph node dissection.Results:In the group of improved lateral lymph node dissection, five patients had positive lateral node including four poorly differentiated adenocarcinoma and one mucinous cell carcinoma. Compared with the group without improved lateral lymph node dissection, the group of improved lateral lymph node dissection showed significant difference in sexual disturbance, dysuresia and operation duration (P<0.05), but not in the presence of anastomotic fistula and blood loss during operation (P>0.05). Furthermore, patients had lower rate of pelvis recurrence and better 5-year rate of survival for the group of improved lateral lymph node dissection (P<0.05).Conclusion:Radical resection with improved lateral lymph node dissection may decrease the pelvis recurrence rate and increase survival rate in patients with stageⅢ lower rectal carcinoma.