title: Comparative study of late rectal toxicity in prostate cancer patients treated with low-dose-rate brachytherapy: With or without supplemental external beam radiotherapy.
abstract: Supplemental external beam radiation therapy (sEBRT) is often prescribed in men undergoing low-dose-rate (LDR) brachytherapy. A population of patients was analyzed to assess the effect of sEBRT on late rectal toxicity. It was hypothesized that sEBRT + LDR would be associated with a higher risk of late rectal toxicity.
  
  
  
  This retrospective cohort study examined LDR brachytherapy patients, treated with or without sEBRT, with a minimum of 5-year followup. Longitudinal assessments were evaluated using the computerized patient record system. The Kaplan-Meier method was used for analysis.
  
  
  
  Median followup was 7.5 years for 245 patients from 2004 to 2007. sEBRT was administered to 33.5%. Followup beyond 5 years was available for 89%. Overall rates of Grade ≥2 and ≥3 rectal toxicities were 6.9% and 2.9%, respectively. The risk of Grade ≥2 rectal toxicity was 2.8-fold higher for patients receiving sEBRT (95% confidence interval: 1.1-7.2; p = 0.02). The risk of Grade ≥3 rectal toxicity was 11.9-fold higher for patients who received sEBRT (1.5-97.4, 95% confidence interval; p = 0.003). Six of seven patients with a Grade ≥3 rectal toxicity received sEBRT, including one who required an abdominoperineal resection. Median post-LDR D90, V150, V200, and R100 values were 103.3%, 59.4%, 30.1%, and 0.5 cc.
  
  
  
  In a cohort of LDR brachytherapy patients with high rates of followup, sEBRT + LDR was associated with significantly higher risk of Grade ≥2 and ≥3 late rectal toxicity. This analysis supports previous findings and maintains concern about the supplemental use of external beam radiation therapy with LDR brachytherapy while its benefit for tumor control has yet to be prospectively validated.
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA 23221.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Serrano
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA 23221; Department of Radiation Oncology, Hunter Holmes McGuire VA Medical Center, Richmond, VA 23249. Electronic address: dmoghanaki@vcu.edu.
authors.forename: Drew
authors.initials: D
authors.lastname: Moghanaki
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA 23221.
authors.forename: David
authors.initials: D
authors.lastname: Asher
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA 23221.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Karlin
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA 23221; Department of Radiation Oncology, Hunter Holmes McGuire VA Medical Center, Richmond, VA 23249.
authors.forename: Matthew
authors.initials: M
authors.lastname: Schutzer
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA 23221; Department of Radiation Oncology, Hunter Holmes McGuire VA Medical Center, Richmond, VA 23249.
authors.forename: Michael
authors.initials: M
authors.lastname: Chang
authors.affiliation: Department of Radiation Oncology, Virginia Commonwealth University, Massey Cancer Center, Richmond, VA 23221; Department of Radiation Oncology, Hunter Holmes McGuire VA Medical Center, Richmond, VA 23249.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Hagan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000379:methods*; D015331:Cohort Studies; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology*; D011878:Radiotherapy / Q000379:methods; D011879:Radiotherapy Dosage; D012002:Rectal Diseases / Q000209:etiology*; D012189:Retrospective Studies
keywords: Brachytherapy; External beam radiation therapy; LDR; Prostate; Rectal toxicity