title: Oncological Outcomes of Lateral Pelvic Lymph Node Metastasis in Rectal Cancer Treated With Preoperative Chemoradiotherapy.
abstract: BACKGROUND
  Oncological outcomes of lateral pelvic lymph node metastasis in rectal cancer treated with preoperative chemoradiotherapy remain to be elucidated.
  
  
  OBJECTIVE
  The purpose of this study was to clarify the therapeutic effect of chemoradiotherapy on lateral pelvic lymph node metastasis, the risk factors of lateral pelvic lymph node metastasis, and oncological outcomes of lateral pelvic lymph node dissection after chemoradiotherapy.
  
  
  METHODS
  This was a nonrandomized, retrospective study.
  
  
  METHODS
  The study was conducted at a tertiary referral university hospital.
  
  
  METHODS
  Patients with rectal cancer treated with chemoradiotherapy and radical surgery from 2003 to 2015 (N = 222) were included.
  
  
  METHODS
  Radiation (total, 50.4 Gy in 28 fractions) with concomitant fluorouracil-based chemotherapy was administered. Lateral pelvic lymph nodes with a diameter of ≥8 mm before chemoradiotherapy were selectively dissected.
  
  
  METHODS
  Frequency and risk factors of lateral pelvic lymph node metastasis were examined.
  
  
  RESULTS
  Lateral pelvic lymph node dissection was performed in 31 patients (14.0%), and 16 (51.6%) of these patients were pathologically diagnosed as positive for metastasis. Among the patients treated with total mesorectal excision alone (n = 191), 2 (0.9%) had recurrence in the lateral pelvic lymph node area, which was pathologically confirmed after salvage R0 resection. T category downstaging (73.3% vs 12.5%; p < 0.01) and high histological regression of the primary lesion (73.3% vs 18.8%; p < 0.01) were more frequent in patients with pathologically negative lateral pelvic lymph nodes than in those with positive lateral pelvic lymph nodes. Young age, short distance from the anal verge, and enlarged lateral pelvic lymph node before chemoradiotherapy were associated with lateral pelvic lymph node metastasis.
  
  
  CONCLUSIONS
  The study was limited by its retrospective nature and small study population.
  
  
  CONCLUSIONS
  The incidence of lateral pelvic lymph node metastasis after chemoradiotherapy was estimated to be 8.1% (18/222). Young age, short distance from the anal verge, and enlarged lateral pelvic lymph node before chemoradiotherapy were risk factors of lateral pelvic lymph node metastasis after chemoradiotherapy.
authors.affiliation: 1 Department of Surgical Oncology, University of Tokyo, Tokyo, Japan 2 Department of Pathology, University of Tokyo Hospital, Tokyo, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Ishihara
authors.forename: Kazushige
authors.initials: K
authors.lastname: Kawai
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Tomomichi
authors.initials: T
authors.lastname: Kiyomatsu
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hata
authors.forename: Hioaki
authors.initials: H
authors.lastname: Nozawa
authors.forename: Teppei
authors.initials: T
authors.lastname: Morikawa
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology / Q000473:pathology / Q000628:therapy; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D059248:Chemoradiotherapy / Q000009:adverse effects / Q000379:methods; D003082:Colectomy / Q000009:adverse effects / Q000379:methods; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use*; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008197:Lymph Node Excision / Q000379:methods*; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000453:epidemiology; D009367:Neoplasm Staging; D010388:Pelvis; D012004:Rectal Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000628:therapy; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000964:Antimetabolites, Antineoplastic; D005472:Fluorouracil