title: Oncologic outcome after preoperative chemoradiotherapy in patients with pathologic T0 (ypT0) rectal cancer.
abstract: BACKGROUND
  Little is known about the oncologic outcomes of patients with ypT0 rectal cancer after preoperative chemoradiotherapy.
  
  
  OBJECTIVE
  To evaluate the clinicopathologic characteristics and oncologic outcomes of patients with ypT0 rectal cancer after preoperative chemoradiotherapy and curative radical surgery.
  
  
  METHODS
  This was a retrospective review of factors influencing outcome of patients treated with preoperative chemoradiotherapy for rectal cancer at a tertiary care university medical center in Seoul, Korea between 2000 and 2008.
  
  
  METHODS
  A total of 830 rectal cancer patients underwent surgery after preoperative chemoradiotherapy. Patients were included in the study if they had a pretreatment clinical classification of T3-4 or N+ (or T2N0 and preoperative chemoradiotherapy for sphincter preservation) and if they were classified on pathologic examination as ypT0 after preoperative CRT and curative radical surgery. Patients were classified as.
  
  
  METHODS
  Overall survival and disease-free survival were evaluated in relation to ypT0N0 or ypT0N1-2 status and other factors that might influence outcome.
  
  
  RESULTS
  Of 91 patients included in the study, 54 (59.3%) were men; the mean patient age was 55 (SD, 11) years, and mean follow-up duration was 44 (SD, 23) months. Surgical procedures included low anterior resection in 68 patients, abdominoperineal resection in 21, and intersphincteric resection in 2. Mean tumor distance from the anal verge was 4.7 (SD, 1.8) cm. Of the 91 patients, 85 were classified as ypT0N0 and 6 as ypT0N1-2. No patient experienced local recurrence. A total of 11 patients (12.1%) had distant metastases, after a mean 11.1 months, including 7 (8.2%) with ypT0N0 and 4 (66.7%) with ypT0N1-2 tumors. One patient with ypT0N0 and 2 patients with ypT0N1-2 tumors died of metastasis. In patients classified as ypT0N0, the 5-year disease free survival and overall survival rates were 82.3% and 89.2%, respectively. Multivariate analysis showed that ypN1-2 status (p = 0.001) was a significant independent risk factor for recurrence (decreased 5-year disease-free survival), but no factor was associated with 5-year overall survival.
  
  
  CONCLUSIONS
  The study is limited by its retrospective nature.
  
  
  CONCLUSIONS
  Oncologic outcomes in patients with ypT0N0 rectal cancer were excellent. The presence of residual cancer cells in mesorectal lymph nodes represents a risk factor for distant metastasis.
authors.affiliation: Department of Colon and Rectal Surgery, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Tae Young
authors.initials: TY
authors.lastname: Jang
authors.forename: Chang Sik
authors.initials: CS
authors.lastname: Yu
authors.forename: Yong Sik
authors.initials: YS
authors.lastname: Yoon
authors.forename: Seok-Byung
authors.initials: SB
authors.lastname: Lim
authors.forename: Seung-Mo
authors.initials: SM
authors.lastname: Hong
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: D000704:Analysis of Variance; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001706:Biopsy; D059248:Chemoradiotherapy; D003131:Combined Modality Therapy; D013505:Digestive System Surgical Procedures; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D056910:Republic of Korea; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents