Treating patients with advanced rectal cancer and lateral pelvic lymph nodes with preoperative chemoradiotherapy based on pretreatment imaging

Preoperative chemoradiotherapy (CRT) and lateral pelvic lymph node (LPLN) dissection (LPLD) based on pretreatment imaging are performed to improve oncological outcomes at our institution. However, the advantage of LPLD following preoperative CRT in advanced rectal cancer remains unclear. The objective of the present study was to assess the validity of this approach. Thirty-two patients with advanced rectal cancer were included in the study. All patients were treated with preoperative CRT and curative operation. Of these, 16 patients who were treated between August 2005 and June 2008 underwent LPLD on both sides (LPLD group). Sixteen patients who were treated between July 2008 and January 2013 underwent LPLD only on the side with suspected LPLN metastasis determined by pretreatment imaging; in cases without LPLN metastasis, only total mesorectal excision was performed (limited-LPLD group). The overall survival and relapse-free survival between the LPLD and the limited-LPLD groups were compared. Preoperative CRT was able to lower clinical lymph node status in 50% of the cases. In addition, pathological lymph node status did not exceed the pretreatment clinical lymph node status stage in the LPLD group. There were no differences in the overall survival and relapse-free survival between the two groups (P=0.729 and P=0.874, respectively). We conclude that multi-imaging studies have a very low risk of overlooking pathologically positive LPLN metastases. Therefore, limited LPLD is a feasible strategy for patients with advanced rectal cancer and suspicious LPLN metastases based on pretreatment imaging.