title: Quality of life and toxicity from passively scattered and spot-scanning proton beam therapy for localized prostate cancer.
abstract: OBJECTIVE
  To report quality of life (QOL)/toxicity in men treated with proton beam therapy for localized prostate cancer and to compare outcomes between passively scattered proton therapy (PSPT) and spot-scanning proton therapy (SSPT).
  
  
  METHODS
  Men with localized prostate cancer enrolled on a prospective QOL protocol with a minimum of 2 years' follow-up were reviewed. Comparative groups were defined by technique (PSPT vs SSPT). Patients completed Expanded Prostate Cancer Index Composite questionnaires at baseline and every 3-6 months after proton beam therapy. Clinically meaningful differences in QOL were defined as ≥0.5 × baseline standard deviation. The cumulative incidence of modified Radiation Therapy Oncology Group grade ≥2 gastrointestinal (GI) or genitourinary (GU) toxicity and argon plasma coagulation were determined by the Kaplan-Meier method.
  
  
  RESULTS
  A total of 226 men received PSPT, and 65 received SSPT. Both PSPT and SSPT resulted in statistically significant changes in sexual, urinary, and bowel Expanded Prostate Cancer Index Composite summary scores. Only bowel summary, function, and bother resulted in clinically meaningful decrements beyond treatment completion. The decrement in bowel QOL persisted through 24-month follow-up. Cumulative grade ≥2 GU and GI toxicity at 24 months were 13.4% and 9.6%, respectively. There was 1 grade 3 GI toxicity (PSPT group) and no other grade ≥3 GI or GU toxicity. Argon plasma coagulation application was infrequent (PSPT 4.4% vs SSPT 1.5%; P=.21). No statistically significant differences were appreciated between PSPT and SSPT regarding toxicity or QOL.
  
  
  CONCLUSIONS
  Both PSPT and SSPT confer low rates of grade ≥2 GI or GU toxicity, with preservation of meaningful sexual and urinary QOL at 24 months. A modest, yet clinically meaningful, decrement in bowel QOL was seen throughout follow-up. No toxicity or QOL differences between PSPT and SSPT were identified. Long-term comparative results in a larger patient cohort are warranted.
authors.affiliation: Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Pugh
authors.forename: Mark F
authors.initials: MF
authors.lastname: Munsell
authors.forename: Seungtaek
authors.initials: S
authors.lastname: Choi
authors.forename: Quyhn Nhu
authors.initials: QN
authors.lastname: Nguyen
authors.forename: Benson
authors.initials: B
authors.lastname: Mathai
authors.forename: X Ron
authors.initials: XR
authors.lastname: Zhu
authors.forename: Narayan
authors.initials: N
authors.lastname: Sahoo
authors.forename: Michael
authors.initials: M
authors.lastname: Gillin
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Johnson
authors.forename: Richard A
authors.initials: RA
authors.lastname: Amos
authors.forename: Lei
authors.initials: L
authors.lastname: Dong
authors.forename: Usama
authors.initials: U
authors.lastname: Mahmood
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Kuban
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Frank
authors.forename: Karen E
authors.initials: KE
authors.lastname: Hoffman
authors.forename: Sean E
authors.initials: SE
authors.lastname: McGuire
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D007422:Intestines / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects*; D011446:Prospective Studies; D011467:Prostate / Q000528:radiation effects; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D061766:Proton Therapy / Q000009:adverse effects* / Q000379:methods; D011788:Quality of Life; D012542:Scattering, Radiation; D012669:Seminal Vesicles / Q000528:radiation effects; D019529:Sexuality / Q000528:radiation effects; D001743:Urinary Bladder / Q000528:radiation effects; D014555:Urination Disorders / Q000209:etiology