Evaluation of lateral lymph node dissection with preoperative chemo-radiotherapy for the treatment of advanced middle to lower rectal cancers

Background and aims. This study examined rectal cancers with lateral lymph node (LN) metastases and whether lateral lymph node dissection (LLD) with or without preoperative chemo-radiotherapy (XRT) benefits patients with rectal cancer. Patients and methods. A total of 452 consecutive cases of curatively resected pT2, pT3, and pT4 middle to lower rectal cancers were retrospectively analyzed. Of these, 265 patients underwent curative LLD and 155 XRT. Data were evaluated with respect to the cumulative percentage of survival. Results. Lateral LN metastases were identified in 7.7% of patients. Of the pT3/pT4 extraperitoneal cancer patients 13.5/18.8% had lateral LN metastases. In the treatment of middle rectal cancers and pT2 extraperitoneal cancers LLD either with or without XRT did not improve survival rate. For the treatment of pT3/pT4 extraperitoneal tumors prior to the introduction of total mesorectal excision (TME) in 1994 LLD plus XRT yielded significantly better survival and local control than conventional surgery without LLD or XRT, although LLD alone did not improve either survival or local recurrence rates. Since 1995 TME with or without subsequent LLD has yielded favorable results for the treatment of extraperitoneal tumors. Conclusion. For the treatment of middle rectal cancers and pT2 extraperitoneal cancers LLD either with or without XRT does not improve survival rate. For pT3/pT4 extraperitoneal tumors, which are associated with a high incidence of lateral node metastasis, combining treatment modalities such as TME followed by LLD or XRT followed by TME may be considered.