Post-prostatectomy image-guided radiation therapy: Evaluation of toxicity and inter-fraction variation using online cone-beam CT

Harriet B. Eldredge, Matthew Studenski, Scott W. Keith, Edouard Trabulsi, Costas D. Lallas, Leonard G. Gomella, Adam P. Dicker, Timothy N. Showalter

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Purpose: The purpose of this study is to assess the acute and late genitourinary (GU) and gastrointestinal (GI) toxicities of cone-beam computed tomography (CBCT) guided conformal adjuvant and salvage post-prostatectomy radiotherapy (RT) compared with RT with port films. Materials and methods: Sixty-eight patients (group 1) were treated with RT following radical prostatectomy (RP) using CBCT-guided conformal RT to a median dose of 68.4 Gy. CBCT images were acquired three to five times weekly and were automatically co-registered to a reference CT. A comparative group (group 2) included 150 patients who received post-RP RT with weekly port films to a median dose of 64.8 Gy. GU and GI toxicities were graded in both the acute and late settings using Radiation Therapy Oncology Group criteria. Associations between toxicity and study variables were evaluated by odds ratios (ORs) estimated by logistic regression. Results: Grades 2 and 3 acute GU toxicity were experienced by 13% (n = 9) and 2% (n = 1) of patients in group 1, respectively, while 13% (n = 19) had grade 2 acute GU toxicity in the control group (group 2). Grade 2 acute GI toxicity was experienced by 13% (n = 9) and 15% (n = 23) in groups 1 and 2, respectively. Acute GU (P = 0.67) and GI (P = 0.84) toxicities were not significantly different between the two groups. There were no associations detected between CBCT and acute GI toxicity (OR 0.76, P = 0.57) or acute GU (OR 1.16, P = 0.75). Increased odds of acute GU toxicity were observed for doses > 68.4 Gy (OR 12.81, P = 0.04), which were only delivered in the CBCT group. CBCT mean variations (standard deviation) for 1053 fractions were 2.8 mm (2.8), 2.0 mm (2.4) and 3.1 mm (2.9) in the left-to-right, anterior-to-posterior (AP) and superior-to-inferior (SI) axes, respectively. Corrective shifts for variance â?¥ 5 mm were required for 15%, 6% and 19% of fractions in the left-to-right, anterior-to-posterior and superior-to-inferior axes, respectively. Conclusions: Rates of acute toxicity with CBCT-guided post-RP RT to 68.4 Gy were similar to treatment to 64.8 Gy without image-guidance RT. Acceptable early toxicity profiles suggest that CBCT is a reasonable strategy for image guidance, but the value of CBCT must be weighed against potential increased risk of secondary cancers due to increased radiation exposure.

Original languageEnglish (US)
Pages (from-to)507-515
Number of pages9
JournalJournal of Medical Imaging and Radiation Oncology
Volume55
Issue number5
DOIs
StatePublished - Oct 1 2011
Externally publishedYes

Keywords

  • cone-beam CT
  • post-prostatectomy
  • prostate cancer
  • radiation therapy

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging

Fingerprint Dive into the research topics of 'Post-prostatectomy image-guided radiation therapy: Evaluation of toxicity and inter-fraction variation using online cone-beam CT'. Together they form a unique fingerprint.

  • Cite this