title: Orthovoltage intraoperative radiotherapy for locally advanced and recurrent colorectal cancer.
abstract: BACKGROUND
  Locally advanced and recurrent colorectal cancers pose a significant therapeutic challenge. Orthovoltage intraoperative radiotherapy provides one potential means of improving disease control at the time of surgery.
  
  
  OBJECTIVE
  This study sought to analyze outcomes and identify prognostic factors of patients treated with orthovoltage intraoperative radiotherapy for locally advanced or recurrent colorectal cancer.
  
  
  METHODS
  This study is a retrospective chart review conducted at a tertiary medical center.
  
  
  METHODS
  Between January 1990 and July 2009, 55 patients underwent intraoperative radiotherapy to a total of 61 sites for locally advanced (n = 14) or recurrent (n = 41) cancers of colon (n = 18) or rectum/rectosigmoid junction (n = 37).
  
  
  METHODS
  Median dose was 12 Gy (range, 7.5-20 Gy). Among locally advanced rectal/rectosigmoid cases, surgery included abdominoperineal resection (n = 3) or low anterior resection (n = 9). Seven treated sites had gross residual (R2) disease, 28 had pathologic or clinical microscopic residual disease (R1), and 15 were complete resections (R0). Treated sites included sacrum (n = 22), anterior pelvis/pelvic sidewall (19), sacrum and sidewall (n = 1), aortic bifurcation (n = 2), vaginal cuff (n = 2), psoas (n = 3), perivesicular region (n = 2), and other (n = 10).
  
  
  METHODS
  Outcomes measures included in-field local control, locoregional control, overall survival, and grade ≥3 toxicity.
  
  
  RESULTS
  At a median follow-up of 27 months (range, 4-237) among living patients, 2-year Kaplan-Meier estimates of in-field local control, locoregional control, and overall survival were 69%, 51%, and 59%. Margin status predicted for improved locoregional control (p = 0.01) and overall survival (p = 0.01). Seventeen patients (31%) developed a grade 3 to 5 toxicity following surgery with intraoperative radiotherapy.
  
  
  CONCLUSIONS
  This study was limited by its retrospective nature and relatively small sample size.
  
  
  CONCLUSIONS
  Local control with intraoperative radiotherapy for locally advanced and recurrent colorectal cancers is good despite the high risk of residual disease. Among carefully selected patients, multimodality regimens including intraoperative radiotherapy may permit long-term survival.
authors.affiliation: Department of Radiation Oncology, University of California Davis, Sacramento, California 95817, USA. megan.daly@ucdmd.ucdavis.edu
authors.forename: Megan E
authors.initials: ME
authors.lastname: Daly
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Kapp
authors.forename: Peter G
authors.initials: PG
authors.lastname: Maxim
authors.forename: Mark L
authors.initials: ML
authors.lastname: Welton
authors.forename: Phuoc T
authors.initials: PT
authors.lastname: Tran
authors.forename: Albert C
authors.initials: AC
authors.lastname: Koong
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Chang
mesh_terms: D015179:Colorectal Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007430:Intraoperative Care; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D011379:Prognosis; D016016:Proportional Hazards Models; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D016896:Treatment Outcome