title: Role of Adjuvant Chemotherapy in ypT0-2N0 Patients Treated with Preoperative Chemoradiation Therapy and Radical Resection for Rectal Cancer.
abstract: OBJECTIVE
  To explore the role of adjuvant chemotherapy for patients with ypT0-2N0 rectal cancer treated by preoperative chemoradiation therapy (PCRT) and radical resection.
  
  
  METHODS
  A national consortium of 10 institutions was formed, and patients with ypT0-2N0 mid- and low-rectal cancer after PCRT and radical resection from 2004 to 2009 were included. Patients were categorized into 2 groups according to receipt of additional adjuvant chemotherapy: Adj CTx (+) versus Adj CTx (-). Propensity scores were calculated and used to perform matched and adjusted analyses comparing relapse-free survival (RFS) between treatment groups while controlling for potential confounding.
  
  
  RESULTS
  A total of 1016 patients, who met the selection criteria, were evaluated. Of these, 106 (10.4%) did not receive adjuvant chemotherapy. There was no overall improvement in 5-year RFS as a result of adjuvant chemotherapy [91.6% for Adj CTx (+) vs 87.5% for Adj CTx (-), P=.18]. There were no differences in 5-year local recurrence and distant metastasis rate between the 2 groups. In patients who show moderate, minimal, or no regression in tumor regression grade, however, possible association of adjuvant chemotherapy with RFS would be considered (hazard ratio 0.35; 95% confidence interval 0.14-0.88; P=.03). Cox regression analysis after propensity score matching failed to show that addition of adjuvant chemotherapy was associated with improved RFS (hazard ratio 0.81; 95% confidence interval 0.39-1.70; P=.58).
  
  
  CONCLUSIONS
  Adjuvant chemotherapy seemed to not influence the RFS of patients with ypT0-2N0 rectal cancer after PCRT followed by radical resection. Thus, the addition of adjuvant chemotherapy needs to be weighed against its oncologic benefits.
authors.affiliation: Department of Colon and Rectal Surgery, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: In Ja
authors.initials: IJ
authors.lastname: Park
authors.affiliation: Center for Colorectal Cancer, National Cancer Center, Goyang-si, Korea.
authors.forename: Dae Yong
authors.initials: DY
authors.lastname: Kim
authors.affiliation: Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hee Cheol
authors.initials: HC
authors.lastname: Kim
authors.affiliation: Section of Colon and Rectal Surgery, Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Nam Kyu
authors.initials: NK
authors.lastname: Kim
authors.affiliation: Department of Surgery, Chonnam National University Hwansun Hospital, Gwangju, Korea.
authors.forename: Hyeong-Rok
authors.initials: HR
authors.lastname: Kim
authors.affiliation: Department of Surgery, Seoul National University Bungdang Hospital, Bundang, Korea.
authors.forename: Sung-Bum
authors.initials: SB
authors.lastname: Kang
authors.affiliation: Division of Colorectal Cancer Center, Kyungpook National University Medical Center, Daegu, Korea.
authors.forename: Gyu-Seog
authors.initials: GS
authors.lastname: Choi
authors.affiliation: Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kang Young
authors.initials: KY
authors.lastname: Lee
authors.affiliation: Department of Surgery, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Seon-Hahn
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Surgery, Seoul St. Mary Hospital, Catholic University, Seoul, Korea.
authors.forename: Seung Taek
authors.initials: ST
authors.lastname: Oh
authors.affiliation: Department of Colon and Rectal Surgery, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Seok-Byung
authors.initials: SB
authors.lastname: Lim
authors.affiliation: Department of Colon and Rectal Surgery, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Jin Cheon
authors.initials: JC
authors.lastname: Kim
authors.affiliation: Center for Colorectal Cancer, National Cancer Center, Goyang-si, Korea.
authors.forename: Jae Hwan
authors.initials: JH
authors.lastname: Oh
authors.affiliation: Center for Colorectal Cancer, National Cancer Center, Goyang-si, Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Woo Yong
authors.initials: WY
authors.lastname: Lee
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Jung Bok
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Department of Colon and Rectal Surgery, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea. Electronic address: csyu@amc.seoul.kr.
authors.forename: Chang Sik
authors.initials: CS
authors.lastname: Yu
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology* / Q000556:secondary / Q000601:surgery / Q000628:therapy*; D000368:Aged; D001003:Anal Canal; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D000069287:Capecitabine; D059186:Chemoradiotherapy, Adjuvant; D017024:Chemotherapy, Adjuvant; D016001:Confidence Intervals; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives; D018572:Disease-Free Survival; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000031:analogs & derivatives; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D059351:Organ Sparing Treatments; D011300:Preoperative Care; D057216:Propensity Score; D011879:Radiotherapy Dosage; D012004:Rectal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery / Q000628:therapy*; D012044:Regression Analysis; D016896:Treatment Outcome
chemical_list: D003841:Deoxycytidine; D000069287:Capecitabine; D005472:Fluorouracil