title: Combined modality therapy including intraoperative electron irradiation for locally recurrent colorectal cancer.
abstract: OBJECTIVE
  To evaluate survival, relapse patterns, and prognostic factors in patients with colorectal cancer relapse treated with curative-intent therapy, including intraoperative electron radiation therapy (IOERT).
  
  
  METHODS
  From April 1981 through January 2008, 607 patients with recurrent colorectal cancer received IOERT as a component of treatment. IOERT was preceded or followed by external radiation (median dose, 45.5 Gy) in 583 patients (96%). Resection was classified as R0 in 227 (37%), R1 in 224 (37%), and R2 in 156 (26%). The median IOERT dose was 15 Gy (range, 7.5-30 Gy).
  
  
  RESULTS
  Median overall survival was 36 months. Five- and 10-year survival rates were 30% and 16%, respectively. Survival estimates at 5 years were 46%, 27%, and 16% for R0, R1, and R2 resection, respectively. Multivariate analysis revealed that R0 resection, no prior chemotherapy, and more recent treatment (in the second half of the series) were associated with improved survival. The 3-year cumulative incidence of central, local, and distant relapse was 12%, 23%, and 49%, respectively. Central and local relapse were more common in previously irradiated patients and in those with subtotal resection. Toxicity Grade 3 or higher partially attributable to IOERT was observed in 66 patients (11%). Neuropathy was observed in 94 patients (15%) and was more common with IOERT doses exceeding 12.5 Gy.
  
  
  CONCLUSIONS
  Long-term survival and disease control was achievable in patients with locally recurrent colorectal cancer. Continued evaluation of curative-intent, combined-modality therapy that includes IOERT is warranted in this high-risk population.
authors.affiliation: Department of Radiation Oncology, Mayo Clinic, Rochester, MN 55905, USA. haddock.michael@mayo.edu
authors.forename: Michael G
authors.initials: MG
authors.lastname: Haddock
authors.forename: Robert C
authors.initials: RC
authors.lastname: Miller
authors.forename: Heidi
authors.initials: H
authors.lastname: Nelson
authors.forename: John H
authors.initials: JH
authors.lastname: Pemberton
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Dozois
authors.forename: Steven R
authors.initials: SR
authors.lastname: Alberts
authors.forename: Leonard L
authors.initials: LL
authors.lastname: Gunderson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D003131:Combined Modality Therapy / Q000379:methods / Q000401:mortality; D004583:Electrons / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007430:Intraoperative Care; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D011832:Radiation Injuries / Q000473:pathology; D011879:Radiotherapy Dosage; D012004:Rectal Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D015996:Survival Rate; D055815:Young Adult