title: Preoperative chemoradiotherapy with concomitant small field boost irradiation for locally advanced rectal cancer: a multi-institutional phase II study (KROG 04-01).
abstract: OBJECTIVE
  This study was designed to determine the effect of concomitant small field boost irradiation given during preoperative chemoradiotherapy for patients with locally advanced rectal cancer.
  
  
  METHODS
  The study prospectively enrolled 38 patients scheduled for preoperative chemoradiotherapy. Pelvic radiotherapy of 43.2 Gy/24 fractions was delivered and boost radiotherapy of 7.2 Gy/12 fractions was concomitantly administered during the latter half of the pelvic radiotherapy treatment period. Two cycles of a bolus 5-fluorouracil and leucovorin injection in the first and fifth weeks of radiotherapy were administered. The median time to surgery after completion of chemoradiotherapy was six weeks. Tumor responses to chemoradiotherapy were assessed by using magnetic resonance volumetry and post-chemoradiotherapy pathology tests to determine tumor downstaging and tumor regression rate.
  
  
  RESULTS
  Thirty-six of 38 patients (94.7 percent) underwent the scheduled surgery. The mean tumor volume reduction rate was 70.3 percent, and the clinical response rate was 66.7 percent. The downstaging rates were 41.7 percent for T classification, 85.2 percent for N classification, and 72.2 percent for stage. Tumor regression grades after preoperative chemoradiotherapy were Grade 1 in 5 patients (13.9 percent), Grade 2 in 24 patients (66.7 percent), Grade 3 in 3 patients (8.3 percent), and Grade 4 in 4 patients (11.1 percent). Ten patients (26.3 percent) experienced > or = Grade 3 acute toxicity.
  
  
  CONCLUSIONS
  Our data suggest that concomitant boost irradiation does not improve clinical outcomes compared with other published preoperative chemoradiotherapy regimens. In addition, the clinicians choosing to use concomitant small field boost irradiation should be cautious to minimize the risk of unplanned sphincter ablation.
authors.affiliation: Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang, South Korea.
authors.forename: Dae Yong
authors.initials: DY
authors.lastname: Kim
authors.forename: Tae Hyun
authors.initials: TH
authors.lastname: Kim
authors.forename: Kyung Hae
authors.initials: KH
authors.lastname: Jung
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Chang
authors.forename: Seok-Byung
authors.initials: SB
authors.lastname: Lim
authors.forename: Hyo Seong
authors.initials: HS
authors.lastname: Choi
authors.forename: Seung-Yong
authors.initials: SY
authors.lastname: Jeong
authors.forename: Taek-Keun
authors.initials: TK
authors.lastname: Nam
authors.forename: Seong Yeob
authors.initials: SY
authors.lastname: Ryu
authors.forename: Doo Suk
authors.initials: DS
authors.lastname: Lee
authors.forename: Sung Il
authors.initials: SI
authors.lastname: Choi
authors.forename: Jin Hyung
authors.initials: JH
authors.lastname: Kang
authors.forename: Sei-Chul
authors.initials: SC
authors.lastname: Yoon
mesh_terms: D000328:Adult; D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D019583:Dose Fractionation, Radiation; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D006801:Humans; D007275:Injections, Intravenous; D002955:Leucovorin / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D011446:Prospective Studies; D020266:Radiotherapy, Conformal / Q000379:methods; D012004:Rectal Neoplasms / Q000473:pathology / Q000628:therapy*; D014803:Vitamin B Complex / Q000627:therapeutic use
chemical_list: D000964:Antimetabolites, Antineoplastic; D014803:Vitamin B Complex; D002955:Leucovorin; D005472:Fluorouracil