title: A logistic model including risk factors for lymph node metastasis can improve the accuracy of magnetic resonance imaging diagnosis of rectal cancer.
abstract: BACKGROUND
  To evaluate use of magnetic resonance imaging (MRI) and a logistic model including risk factors for lymph node metastasis for improved diagnosis.
  
  
  METHODS
  The subjects were 176 patients with rectal cancer who underwent preoperative MRI. The longest lymph node diameter was measured and a cut-off value for positive lymph node metastasis was established based on a receiver operating characteristic (ROC) curve. A logistic model was constructed based on MRI findings and risk factors for lymph node metastasis extracted from logistic-regression analysis. The diagnostic capabilities of MRI alone and those of the logistic model were compared using the area under the curve (AUC) of the ROC curve.
  
  
  RESULTS
  The cut-off value was a diameter of 5.47 mm. Diagnosis using MRI had an accuracy of 65.9%, sensitivity 73.5%, specificity 61.3%, positive predictive value (PPV) 62.9%, and negative predictive value (NPV) 72.2% [AUC: 0.6739 (95%CI: 0.6016-0.7388)]. Age (<59) (p=0.0163), pT (T3+T4) (p=0.0001), and BMI (<23.5) (p=0.0003) were extracted as independent risk factors for lymph node metastasis. Diagnosis using MRI with the logistic model had an accuracy of 75.0%, sensitivity 72.3%, specificity 77.4%, PPV 74.1%, and NPV 75.8% [AUC: 0.7853 (95%CI: 0.7098-0.8454)], showing a significantly improved diagnostic capacity using the logistic model (p=0.0002).
  
  
  CONCLUSIONS
  A logistic model including risk factors for lymph node metastasis can improve the accuracy of MRI diagnosis of rectal cancer.
authors: Department of Surgery II, Tokyo Women's Medical University School of Medicine, Shinjuku-ku, Tokyo, Japan E-mail : itabashi@surg2.twmu.ac.jp.
authors: Shimpei
authors: S
authors: Ogawa
authors: Michio
authors: M
authors: Itabashi
authors: Tomoichiro
authors: T
authors: Hirosawa
authors: Takuzo
authors: T
authors: Hashimoto
authors: Yoshiko
authors: Y
authors: Bamba
authors: Shingo
authors: S
authors: Kameoka
mesh_terms: D000230:Adenocarcinoma / Q000556:secondary*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000473:pathology*; D012307:Risk Factors