title: Comparison of recurrence patterns between ≤5 years and >5 years after curative operations in colorectal cancer patients.
abstract: OBJECTIVE
  To identify characteristics of recurrent colorectal cancer in terms of follow-up periods, that is, ≤5 years and >5 years after curative operations
  
  
  METHODS
  This study enrolled 4,023 patients. Of them, 835 patients showed recurrence after primary curative resection for colorectal cancer. Recurrence occurred ≤5 years (n = 799) or >5 years (n = 36) after curative surgery. Variables and recurrence patterns were compared between the groups.
  
  
  RESULTS
  Among the 835 patients who experienced recurrence, only 4.3% recurred >5 years after surgery. This group showed lower preoperative serum carcinoembryonic antigen levels, more tumors with expanding growth, well-differentiated histology, and no lymph node metastasis (all P < 0.05). In terms of haematogenous metastasis, lung or liver was the most prevalent site in patients who recurred after >5 years or ≤5 years, respectively (P = 0.005). In rectal cancer patients, recurrence patterns revealed the same results. In colon cancer patients, the liver was the most prevalent site in both groups.
  
  
  CONCLUSIONS
  After 5 years of follow-up, routine surveillance for detecting other malignancies seems to be sufficient. However, the possibility of late (particularly late pulmonary) recurrence should be considered. Radiologic examination to detect pulmonary metastasis should be considered in the follow-up program.
authors.affiliation: Department of Surgery, University of Ulsan College of Medicine and Asan Medical Centre, Seoul, Republic of Korea.
authors.forename: Seok In
authors.initials: SI
authors.lastname: Seo
authors.forename: Seok-Byung
authors.initials: SB
authors.lastname: Lim
authors.forename: Yong Sik
authors.initials: YS
authors.lastname: Yoon
authors.forename: Chan Wook
authors.initials: CW
authors.lastname: Kim
authors.forename: Chang Sik
authors.initials: CS
authors.lastname: Yu
authors.forename: Tae Won
authors.initials: TW
authors.lastname: Kim
authors.forename: Jong Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Jin Cheon
authors.initials: JC
authors.lastname: Kim
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000628:therapy; D014408:Biomarkers, Tumor / Q000097:blood; D002272:Carcinoembryonic Antigen / Q000097:blood; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000473:pathology* / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary*; D008175:Lung Neoplasms / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen