title: Effects of Preoperative Chemoradiotherapy on the Likelihood of Sphincter Preservation Surgery in Locally Advanced Distal Rectal Cancer: A Longitudinal Study Based on Pelvic Magnetic Resonance Imaging.
abstract: BACKGROUND
  It is unclear whether preoperative chemoradiotherapy (pCRT) increases the rate of sphincter-preserving surgery (SPS), avoiding abdominoperineal resection (APR), for the treatment of distal rectal cancer. We examined whether pCRT increases the likelihood of SPS based on changes in tumor height using pelvic magnetic resonance imaging (MRI).
  
  
  METHODS
  Between January 2009 and December 2013, 105 patients underwent long-course pCRT for locally advanced distal rectal cancer (≤5 cm from the anal verge) and were included in this study. The surgical procedures were analyzed in terms of radiologic findings, including the distance from the inferior margin of tumor to the superior margin of the anorectal ring (tumor height) measured by pelvic MRI before and after pCRT.
  
  
  RESULTS
  Eighty-six (81.9 %) patients underwent SPS. Overall clinical downstaging occurred in 48 (45.7 %) patients. Tumor height increased significantly after pCRT (from 15.0 ± 15.3 to 18.1 ± 16.9 mm, change 3.1 ± 9.7 mm, p = 0.01). The mean change in tumor height was not significantly different between patients who underwent SPS or APR (mean change 3.3 ± 9.6 vs. 2.3 ± 10.5 mm, p = 0.68). The mean change was significantly greater in the double-stapled anastomosis group than in the handsewn anastomosis group (mean change 5.6 ± 9.9 vs. -0.6 ± 8.6 mm, p = 0.02).
  
  
  CONCLUSIONS
  This was the first MRI-based longitudinal study to show that pCRT does not appear to increase the likelihood of SPS in locally advanced distal rectal cancer, although it could improve the potential of double-stapled anastomoses.
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Myong Hoon
authors.initials: MH
authors.lastname: Ihn
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Kim
authors.forename: Duck-Woo
authors.initials: DW
authors.lastname: Kim
authors.forename: Heung-Kwon
authors.initials: HK
authors.lastname: Oh
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Jin Taek
authors.initials: JT
authors.lastname: Park
authors.forename: Il Tae
authors.initials: IT
authors.lastname: Son
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Park
authors.forename: Yoon Jin
authors.initials: YJ
authors.lastname: Lee
authors.forename: Jin Won
authors.initials: JW
authors.lastname: Kim
authors.forename: Keun-Wook
authors.initials: KW
authors.lastname: Lee
authors.forename: Jee Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Eun
authors.initials: E
authors.lastname: Shin
authors.forename: Hye Seung
authors.initials: HS
authors.lastname: Lee
authors.forename: Soyeon
authors.initials: S
authors.lastname: Ahn
authors.forename: Sung-Bum
authors.initials: SB
authors.lastname: Kang
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000628:therapy*; D000368:Aged; D001003:Anal Canal / Q000503:physiopathology / Q000601:surgery*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D059248:Chemoradiotherapy; D003131:Combined Modality Therapy; D013505:Digestive System Surgical Procedures; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D059351:Organ Sparing Treatments; D011300:Preoperative Care; D011379:Prognosis; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies