title: The important risk factor for lateral pelvic lymph node metastasis of lower rectal cancer is node-positive status on magnetic resonance imaging: study of the Lymph Node Committee of Japanese Society for Cancer of the Colon and Rectum.
abstract: OBJECTIVE
  This study seeks to evaluate lateral pelvic lymph node (LPLN) and perirectal lymph node (PRLN) status on magnetic resonance imaging (MRI) as potential risk factors for lymph node metastasis.
  
  
  METHODS
  The subjects were 394 patients with lower rectal cancer who underwent MRI prior to mesorectal excision (combined with lateral pelvic lymph node dissection in 272 patients) at 6 institutes. No patients received neoadjuvant therapy. Cases were classified as cN(+) and cN(-) based on the short axis of the largest lymph node ≥5 and <5 mm, respectively. LPLN and PRLN status and other clinicopathologic factors were analyzed by multivariate logistic regression. The importance of identified risk factors for lymph node metastasis was examined using the area under the curve (AUC).
  
  
  RESULTS
  Independent risk factors for right LPLN metastasis included histopathological grade (G3 + G4), pPRLN(+), M1, cLPLN(+) [odds ratio (OR) 10.73, 95 % confidence interval (CI) 4.59-27.1], and those for left LPLN metastasis were age (<64), histopathological grade (G3 + G4), pPRLN(+), and cLPLN(+) (OR 24.53, 95 % CI 9.16-77.7). ORs for cLPLN(+) were highest. The AUCs for right and left cLPLN status of 0.7484 (95 % CI 0.6672-0.8153) and 0.7904 (95 % CI 0.7088-0.8538), respectively, were significantly higher than those for other risk factors. In contrast, the ORs for cPRLN(+) and cPRLN status of 2.46 (95 % CI 1.47-4.18) and 0.6396 (95 % CI 0.5917-0.6848) were not much higher than for other factors.
  
  
  CONCLUSIONS
  An LPLN-positive status with a short axis ≥5 mm on MRI is an important predictor of LPLN metastasis, but PRLN status is not a strong predictor of PRLN metastasis.
authors: Department of Surgery II, Tokyo Women's Medical University School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
authors: Shimpei
authors: S
authors: Ogawa
authors: Department of Surgery, Kindai University School of Medicine, 377-2, Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan. hida@surg.med.kindai.ac.jp.
authors: Jin-Ichi
authors: J
authors: Hida
authors: Department of Surgery, Saiseikai Yokohama City Nanbu Hospital, 3-2-10, Kounandai, Kounan-ku, Yokohama, Kanagawa, 234-8503, Japan.
authors: Hideyuki
authors: H
authors: Ike
authors: Department of Surgery, Kurume University School of Medicine, Asahimachi 67 Kurume City, Fukuoka, 830-0011, Japan.
authors: Tetsushi
authors: T
authors: Kinugasa
authors: Gastroenterological Center, Yokohama City University Medical Center, 4-57 Urafunecho, Minami-ku, Yokohama, Kanagawa, 232-0024, Japan.
authors: Mitsuyoshi
authors: M
authors: Ota
authors: Department of Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan.
authors: Eiji
authors: E
authors: Shinto
authors: Department of Surgery, Institute of Gastroenterology, Tokyo Women's Medical University School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
authors: Michio
authors: M
authors: Itabashi
authors: Department of Surgery II, Tokyo Women's Medical University School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
authors: Takahiro
authors: T
authors: Okamoto
authors: Department of Surgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
authors: Kenichi
authors: K
authors: Sugihara
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012004:Rectal Neoplasms / Q000473:pathology*; D012307:Risk Factors; D012955:Societies, Medical; D055815:Young Adult
keywords: Lateral pelvic lymph node (LPLN); Magnetic resonance imaging (MRI); Perirectal lymph node (PRLN); Rectal cancer