title: The impact of lymph node size to predict nodal metastasis in patients with rectal cancer after preoperative chemoradiotherapy.
abstract: OBJECTIVE
  During restaging after preoperative chemoradiotherapy (CRT), the assessment of lymph node (LN) metastasis is vital for selecting further treatment strategies. This study aimed to evaluate the impact of LN size to predict LN metastasis in rectal cancer patients after preoperative CRT.
  
  
  METHODS
  A total of 30 consecutive patients who underwent preoperative CRT followed by curative resection of primary rectal cancer were selected as a study group (CRT group). As a control group (non-CRT group), 30 patients who underwent primary tumor resection were selected using a 1:1 case-match design. Matching criteria were gender, age, and clinical T stage. The size of each LN was measured from the surgical specimen. To clarify optimal cutoff values for node size according to the risk of detecting metastasis, receiving-operator characteristic (ROC) curves were generated.
  
  
  RESULTS
  In the non-CRT group, 39/474 LNs were confirmed to have metastasis. In the CRT group, 29/422 LNs showed metastasis. The median size of metastatic LNs was 6.0 mm in CRT group, which was significantly larger than 4.0 mm in the non-CRT group (p = 0.006). The optimal cutoff value for determining metastasis in the CRT group was 4.5 mm, compared to 3.5 mm in the non-CRT group. The accuracy of the cutoff value was much higher in the CRT group (CRT vs. non-CRT, 77.9 vs. 59.9%).
  
  
  CONCLUSIONS
  LN size is a strong indicator for prediction of regional LN metastasis in rectal cancer patients after preoperative CRT, compared to those without CRT.
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul, 135-720, South Korea.
authors.forename: Im-Kyung
authors.initials: IK
authors.lastname: Kim
authors.forename: Jeonghyun
authors.initials: J
authors.lastname: Kang
authors.forename: Beom Jin
authors.initials: BJ
authors.lastname: Lim
authors.forename: Seung-Kook
authors.initials: SK
authors.lastname: Sohn
authors.forename: Kang Young
authors.initials: KY
authors.lastname: Lee
mesh_terms: D000368:Aged; D059186:Chemoradiotherapy, Adjuvant; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011300:Preoperative Care; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery / Q000628:therapy*