title: Factors associated with risk for colorectal cancer recurrence after endoscopic resection of T1 tumors.
abstract: OBJECTIVE
  More information is needed on the long-term outcomes of patients who undergo endoscopic resection of colorectal tumors. We evaluated recurrence of colorectal cancer (CRC) after endoscopic resection or a combination of endoscopic research and surgery for T1 colorectal tumors.
  
  
  METHODS
  We conducted a retrospective study of 389 patients with T1 CRC treated by endoscopic resection from January 1989 to December 2008 in Sapporo, Japan. We compared outcomes between patients who underwent subsequent surgery (ER + SURG, n = 205) and those who did not (ER only, n = 184) and statistically adjusted baseline differences between the groups according to the propensity scores.
  
  
  RESULTS
  There was almost no risk of cancer recurrence among patients without indications for surgery recommended by the Japanese Society for Cancer of the Colon and Rectum (these indications include tumors with vertical margins, deep submucosal invasion, lymphatic or venous invasion, poor differentiation, or high-grade budding). Among patients with indications for surgery, the cumulative risks of recurrence (CRRs) were 3.7% in the ER + SURG group and 20.1% in the ER only group (P = .001). However, the patients with only deep submucosal invasion had a low CRR, even without surgery (2.3% in the ER + SURG group and 3.4% in the ER only groups, P = .867). In contrast, patients with indications for surgery other than deep submucosal invasion (high-risk patients) had much better outcomes when they also underwent surgery (CRRs: 5.8% in the ER + SURG group vs 58.0% in the ER only group, P < .001).
  
  
  CONCLUSIONS
  On the basis of a retrospective study of patients who underwent endoscopic resection for T1 CRC, those with tumors with only submucosal invasion are at low risk for cancer recurrence. However, patients with other high-risk tumor features have greater risks for cancer recurrence and benefit from subsequent surgery.
authors: Department of Gastroenterology, Keiyukai Sapporo Hospital, Sapporo, Japan; Department of Gastroenterology, Nippon Telegraph and Telephone East Corporation, SAPPORO MEDICAL CENTER NTT EC, Sapporo, Hokkaido, Japan. Electronic address: shinji-yoshii@umin.ac.jp.
authors: Shinji
authors: S
authors: Yoshii
authors: Department of Public Health, Sapporo Medical University School of Medicine, Sapporo, Japan; Division of Advanced Medicine Promotion, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
authors: Masanori
authors: M
authors: Nojima
authors: First Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Katsuhiko
authors: K
authors: Nosho
authors: Third Department of Internal Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors: Saori
authors: S
authors: Omori
authors: Department of Surgery, Keiyukai Sapporo Hospital, Sapporo, Japan.
authors: Takaya
authors: T
authors: Kusumi
authors: First Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan; Department of Medical Oncology, Keiyukai Sapporo Hospital, Sapporo, Japan.
authors: Hiroyuki
authors: H
authors: Okuda
authors: Department of Gastroenterology, Keiyukai Sapporo Hospital, Sapporo, Japan.
authors: Hiroyuki
authors: H
authors: Tsukagoshi
authors: Faculty of Health and Welfare Science, Nayoro City University, Nayoro, Japan.
authors: Masahiro
authors: M
authors: Fujita
authors: First Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Hiroyuki
authors: H
authors: Yamamoto
authors: Department of Surgery, Keiyukai Sapporo Hospital, Sapporo, Japan.
authors: Masao
authors: M
authors: Hosokawa
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology / Q000473:pathology; D000368:Aged; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000473:pathology* / Q000601:surgery; D016099:Endoscopy, Gastrointestinal; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
keywords: CI; CRC; CRR; Colon Cancer; ER; ER + SURG; Ip; JSCCR; Japanese Society for Cancer of the Colon and Rectum; LNM; Neoplasm; ProS; Prognostic Factor; Treatment; colorectal cancer; confidence interval; cumulative risk of recurrence; endoscopic resection; lymph node metastasis; pedunculated type; propensity score; subsequent surgery after endoscopic resection