title: Fecal incontinence and radiation dose on anal sphincter in patients with locally advanced rectal cancer (LARC) treated with preoperative chemoradiotherapy: a retrospective, single-institutional study.
abstract: BACKGROUND
  The objective of the study is to determine the correlations among the variables of dose and the sphincter function (SF) in patients with locally advanced rectal cancer treated with preoperative capecitabine/radiotherapy followed by low anterior resection (LAR) + TME.
  
  
  METHODS
  We retrospectively reviewed 92 consecutive patients with LARC treated at our center with LAR from 2006 and more than 2 years free from disease. We re-contoured the anal sphincters (AS) of patients with the help of the radiologist. SF was assessed with the Wexner scale (0-20 points, being punctuation inversely proportional to annal sphincter functionality). All questionnaires were filled out between January 2010 and December 2012. Dosimetric parameters that have been studied include V20, V30, V40, V50, mean dose (Dmean), minimum dose (Dmin), D90(dose received by 90% of the sphincter) and D98.
  
  
  METHODS
  The correlations among the variables of dose and SF were studied by the Spearman correlation coefficient. Differences in SF relating to maximum doses to the sphincter were assessed by the Mann-Whitney test.
  
  
  RESULTS
  Mean Wexner score was 5.5 points higher in those patients with V20> 0 compared to those for which V20= 0 (p = 0.008). In a multivariate regression model, results suggest that the effect of V20on poor anal sphincter control is independent of the effect of distance, with an adjusted OR of 3.42.
  
  
  CONCLUSIONS
  In order to improve the SF in rectal cancer treated with preoperative radiotherapy/capecitabine followed by conservative surgery, the maximum radiation dose to the AS should be limited, when possible, to <20 Gy.
authors.affiliation: Radiation Oncology Department, Complejo Hospitalario de Navarra, Irunlarrea 3, Pamplona, 31008, Spain. fariasde@cfnavarra.es.
authors.forename: F
authors.identifier: http://orcid.org/0000-0003-1288-9356
authors.initials: F
authors.lastname: Arias
authors.affiliation: Radiation Oncology Department, Complejo Hospitalario de Navarra, Irunlarrea 3, Pamplona, 31008, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Eito
authors.affiliation: Radiation Oncology Department, Complejo Hospitalario de Navarra, Irunlarrea 3, Pamplona, 31008, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Asín
authors.affiliation: Radiation Oncology Department, Complejo Hospitalario de Navarra, Irunlarrea 3, Pamplona, 31008, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Mora
authors.affiliation: Department of Statistics, Complejo Hospitalario de Navarra, Pamplona, Spain.
authors.forename: K
authors.initials: K
authors.lastname: Cambra
authors.affiliation: Department of Physics, Complejo Hospitalario de Navarra, Pamplona, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Mañeru
authors.affiliation: Department of Statistics, Complejo Hospitalario de Navarra, Pamplona, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Ibáñez
authors.affiliation: Radiation Oncology Department, Clinica Universitaria de Navarra, Pamplona, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Arbea
authors.affiliation: Medical Oncology Department, Complejo Hospitalario de Navarra, Pamplona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Viudez
authors.affiliation: Medical Oncology Department, Complejo Hospitalario de Navarra, Pamplona, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Hernández
authors.affiliation: Radiation Oncology Department, Clinica Universitaria de Navarra, Pamplona, Spain.
authors.forename: J I
authors.initials: JI
authors.lastname: Arrarás
authors.affiliation: Radiation Oncology Department, Clinica Universitaria de Navarra, Pamplona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Errasti
authors.affiliation: Radiation Oncology Department, Complejo Hospitalario de Navarra, Irunlarrea 3, Pamplona, 31008, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Barrado
authors.affiliation: Radiation Oncology Department, Complejo Hospitalario de Navarra, Irunlarrea 3, Pamplona, 31008, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Campo
authors.affiliation: Radiation Oncology Department, Complejo Hospitalario de Navarra, Irunlarrea 3, Pamplona, 31008, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Visus
authors.affiliation: Radiation Oncology Department, Clinica Universitaria de Navarra, Pamplona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Flamarique
authors.affiliation: Department of Surgery, Complejo Hospitalario de Navarra, Pamplona, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Ciga
mesh_terms: D000230:Adenocarcinoma / Q000556:secondary / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000473:pathology* / Q000528:radiation effects; D059248:Chemoradiotherapy / Q000009:adverse effects*; D005242:Fecal Incontinence / Q000209:etiology* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D011379:Prognosis; D011829:Radiation Dosage; D012004:Rectal Neoplasms / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D015996:Survival Rate
keywords: Anal function; Radiotherapy; Rectal cancer; Sphincter dose