title: Mesorectal and lateral node metastasis and micrometastasis in lower rectal cancer.
abstract: OBJECTIVE
  To study lymph node metastasis and micrometastasis within the mesorectum and lateral pelvic area in lower rectal cancer.
  
  
  METHODS
  Specimens of 96 patients, who underwent total mesorectal excision (TME) and lateral lymph node dissection (LLND), were included.
  
  
  RESULTS
  An average of 19.4 mesorectal lymph nodes were examined. Horizontally, more than 30 percent of involved lymph nodes were located in the outer layer of the mesorectum. Longitudinally, metastasized lymph nodes were harvested from the distal, paratumoral and proximal mesorectum of 6, 42 and 29 specimens, respectively. Fourteen specimens were observed to have circumferential resection margin involvement, while another 3 had micrometastasis. The average amount of harvested lateral pelvic lymph nodes was 12.1. Most (1052/1159) of the lateral nodes were defined as negative. Fourteen and 11 specimens were examined to contain lateral node metastasis and micrometastasis, respectively. Among regions of the lateral pelvic area, middle rectal root (44%), internal iliac (28%) and obturator (20%) were more likely to be involved by cancer spread.
  
  
  CONCLUSIONS
  Complete excision of the mesorectum is essential for local clearance of lower rectal cancer. Mesorectal margin involvement and lateral metastasis underlined the limitation of single surgical procedure, thus suggesting the significance of neoadjuvant therapy.
authors.affiliation: Department of Gastrointestinal Surgery and Institute of Digestive Surgery, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Yong-Yang
authors.initials: YY
authors.lastname: Yu
authors.forename: Cun
authors.initials: C
authors.lastname: Wang
authors.forename: Dan
authors.initials: D
authors.lastname: Xu
authors.forename: Xiao-Gang
authors.initials: XG
authors.lastname: Shen
authors.forename: Si-Qin
authors.initials: SQ
authors.lastname: Ding
authors.forename: Zong-Guang
authors.initials: ZG
authors.lastname: Zhou
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery