Initial report of the genitourinary and gastrointestinal toxicity of post-prostatectomy proton therapy for prostate cancer patients undergoing adjuvant or salvage radiotherapy

Curtiland Deville, Akansha Jain, Wei Ting Hwang, Kristina D. Woodhouse, Stefan Both, Shiyu Wang, Peter E. Gabriel, John P. Christodouleas, Justin Bekelman, Zelig Tochner, Neha Vapiwala

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: To report acute and late genitourinary (GU) and gastrointestinal (GI) toxicities associated with post-prostatectomy proton therapy (PT). Methods: The first 100 consecutive patients from 2010 to 2016 were retrospectively assessed. Baseline characteristics, prospectively graded CTCAE v4.0 toxicities, and patient-reported outcomes were reported. Late outcomes were reported for 79 patients with 3 months minimum follow up. Toxicity-free survival Kaplan-Meier curves were estimated. Logistic regression assessed associations between toxicities and clinical and treatment characteristics (p <.05 significance). Results: Median age, months after surgery, and months of follow-up were respectively 64 years (range 42–77), 25 (5–216), and 25 (0–47). PT received was 70.2 Gy (RBE) (89%), salvage (93%), prostate bed only (80%), pencil beam scanning (86%), with IMRT (31%), and with androgen deprivation (34%). Acute and late maximum toxicities, respectively were: GU grade 0 (14%; 18%), 1 (71%; 62%), 2 (15%; 20%), ≥3 (0), and GI: grade 0 (66%; 73%), 1 (34%; 27%), ≥2 (0). Toxicity-free survival at 24 months was GU grade 2 (83%) and GI grade 1 (74%). Mean (±std dev) baseline International Prostate Symptom Score (IPSS), International Index of Erectile Function, and Expanded Prostate Cancer Index Composite bowel function and bother were 6.6 ± 6.1, 10.5 ± 7.3, 90.9 ± 10.8, 93.3 ± 11.2, respectively, and largely unchanged at 2 years: 6.3 ± 3.6, 11.1 ± 6.3, 92.8 ± 5.8, and 90.9 ± 10.3. On multivariate analysis, baseline IPSS (p =.009) associated with GU grade 2 acute toxicity. Bladderless-CTV median dose, V30, and V40 associated with GU grade 2 acute toxicity and maximum dose with late (Ps <0.05). For GI, on multivariate analysis, baseline bowel function (p =.033) associated with acute grade 1 toxicity. Rectal minimum and median dose, V10, and V20, and anterior rectal wall median dose and V10 through V65 associated with acute grade 1 GI toxicity (Ps <.05). Conclusions: Post-prostatectomy PT for prostate cancer is feasible with a favorable GU and GI toxicity profile acutely and through early follow up.

Original languageEnglish (US)
Pages (from-to)1506-1514
Number of pages9
JournalActa Oncologica
Volume57
Issue number11
DOIs
StatePublished - Nov 2 2018

ASJC Scopus subject areas

  • Hematology
  • Oncology
  • Radiology Nuclear Medicine and imaging

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