title: Comparative toxicity and dosimetric profile of whole-pelvis versus prostate bed-only intensity-modulated radiation therapy after prostatectomy.
abstract: OBJECTIVE
  To assess whether whole-pelvis (WP) intensity modulated radiation therapy (IMRT) for prostate cancer (PCa) after prostatectomy is associated with increased toxicity compared to prostate-bed only (PB) IMRT.
  
  
  METHODS
  All patients (n = 67) undergoing postprostatectomy IMRT to 70.2 Gy at our institution from January 2006 to January 2009 with minimum 12-month follow-up were divided into WP (n = 36) and PB (n = 31) comparison groups. WP patients received initial pelvic nodal IMRT to 45 Gy. Pretreatment demographics, bladder and rectal dose-volume histograms, and maximum genitourinary (GU) and gastrointestinal (GI) toxicities were compared. Logistic regression models evaluated uni- and multivariate associations between pretreatment demographics and toxicities.
  
  
  RESULTS
  Pretreatment demographics including age and comorbidities were similar between groups. WP patients had higher Gleason scores, T stages, and preoperative prostate-specific antigen (PSA) levels, and more WP patients underwent androgen deprivation therapy (ADT). WP minimum (Dmin) and mean bladder doses, bladder volumes receiving more than 5 Gy (V5) and V20, rectal Dmin, and PB bladder and rectal V65 were significantly increased. Maximum acute GI toxicity was Grade 2 and was increased for WP (61%) vs. PB (29%) patients (p = 0.001); there was no significant difference in acute Grade ≥2 GU toxicity (22% WP vs. 10% PB; p = 0.193), late Grade ≥2 GI toxicity (3% WP vs. 0% PB; p = 0.678), or late Grade ≥2 GU toxicity (28% WP vs. 19% PB; p = 0.274) with 25-month median follow-up (range, 12-44 months). On multivariate analysis, long-term ADT use was associated with Grade ≥2 late GU toxicity (p = 0.02).
  
  
  CONCLUSIONS
  Despite dosimetric differences in irradiated bowel, bladder, and rectum, WP IMRT resulted only in clinically significant increased acute GI toxicity in comparison to that with PB IMRT, with no differences in GU or late GI toxicity.
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. deville@uphs.upenn.edu
authors.forename: Curtiland
authors.initials: C
authors.lastname: Deville
authors.forename: Neha
authors.initials: N
authors.lastname: Vapiwala
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Hwang
authors.forename: Haibo
authors.initials: H
authors.lastname: Lin
authors.forename: Voichita Bar
authors.initials: VB
authors.lastname: Ad
authors.forename: Zelig
authors.initials: Z
authors.lastname: Tochner
authors.forename: Stefan
authors.initials: S
authors.lastname: Both
mesh_terms: D000368:Aged; D005500:Follow-Up Studies; D041981:Gastrointestinal Tract / Q000528:radiation effects; D006801:Humans; D015182:Lymphatic Irradiation / Q000379:methods; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D058958:Organs at Risk / Q000528:radiation effects*; D010388:Pelvis; D011182:Postoperative Care / Q000379:methods; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D011832:Radiation Injuries / Q000209:etiology*; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects* / Q000379:methods; D012007:Rectum / Q000528:radiation effects; D012189:Retrospective Studies; D001743:Urinary Bladder / Q000528:radiation effects; D014566:Urogenital System / Q000528:radiation effects
chemical_list: D017430:Prostate-Specific Antigen