title: Resection with en bloc removal of regional lymph node after endoscopic resection for T1 colorectal cancer.
abstract: BACKGROUND
  Various guidelines suggest indications for performing additional colectomy with en bloc removal of regional lymph nodes after endoscopic resection for T1 colon cancer. The aim of this study was to evaluate the pathologic outcomes of patients with surgical treatment after endoscopic resection for T1 colorectal cancer.
  
  
  METHODS
  We used data from 275 patients who had undergone curative resection for T1 colorectal cancer at a single institution between 1991 and 2009. We evaluated the rationale for additional surgical treatment after endoscopic resection performed on 68 of the 275 patients and the association between various clinicopathologic features and lymph node metastasis.
  
  
  RESULTS
  The 5-year overall survival rate was 96.3 %. Reasons for additional surgical treatment included an endoscopic specimen with a pathologically positive margin (n = 20), lymphovascular invasion (n = 25), and submucosal invasion depth of ≥ 1,000 μm (n = 23). When endoscopists failed to find macroscopic cancer residue during endoscopic resection, no pathologically residual cancer was found in the resected specimens. Histologic grade was an independent risk factor for lymph node metastasis (p = 0.028). In the absence of lymphovascular invasion, patients with well-differentiated T1 colorectal cancer did not have nodal involvement.
  
  
  CONCLUSIONS
  Although the outcomes of patients with additional surgical treatment after endoscopic resection for T1 colorectal cancer were satisfactory, excessive and unnecessary treatments may have been performed. Additional surgical treatment after endoscopic resection for T1 colorectal cancer might be unnecessary for patients with well-differentiated adenocarcinoma and no lymphovascular invasion.
authors: Center for Minimally Invasive Surgery, Tokyo Medical and Dental University, Tokyo, Japan. h-kobayashi.srg2@tmd.ac.jp
authors: Hirotoshi
authors: H
authors: Kobayashi
authors: Tetsuro
authors: T
authors: Higuchi
authors: Hiroyuki
authors: H
authors: Uetake
authors: Satoru
authors: S
authors: Iida
authors: Toshiaki
authors: T
authors: Ishikawa
authors: Megumi
authors: M
authors: Ishiguro
authors: Kenichi
authors: K
authors: Sugihara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003082:Colectomy; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D004724:Endoscopy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D009367:Neoplasm Staging; D018365:Neoplasm, Residual / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D011379:Prognosis; D015996:Survival Rate