Dose-Escalated Stereotactic Body Radiation Therapy for Patients with Intermediate and High-Risk Prostate Cancer: Initial Dosimetry Analysis and Patient Outcomes

Publication date: Available online 6 February 2016
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Rupesh Kotecha, Toufik Djemil, Rahul D. Tendulkar, Chandana A. Reddy, Richard A. Thousand, Andrew Vassil, Mark Stovsky, Ryan K. Berglund, Eric A. Klein, Kevin L. Stephans
PurposeTo report the short-term clinical outcomes and acute and late treatment-related genitourinary (GU) and gastrointestinal (GI) toxicities in patients with intermediate- and high-risk prostate cancer treated with dose-escalated stereotactic body radiotherapy (SBRT).Methods and MaterialsBetween 2011 and 2014, 24 patients with prostate cancer were treated with SBRT to the prostate gland and proximal seminal vesicles. A high-dose avoidance zone (HDAZ) was created by a three mm expansion around the rectum, urethra, and bladder. Patients were treated to a minimum dose of 36.25 Gy in five fractions with a simultaneous dose-escalation to a dose of 50 Gy to the target volume away from the HDAZ. Acute and late GU and GI toxicity outcomes were measured according to the National Cancer Institute Common Toxicity Criteria (v4).ResultsThe median follow-up was 25 months (Range: 18-45 months). Nine patients (38%) experienced an acute grade 2 GU toxicity, which was medically managed, and no patients experienced an acute Grade 2 GI toxicity. Two patients (8%) experienced late Grade 2 GU toxicity and two patients (8%) experienced late Grade 2 GI toxicity. No acute or late grade ≥ 3 GU or GI toxicities were observed. The 24-month PSA relapse-free survival outcome for all patients was 95.8% (95% CI: 75.6-99.4%) and both biochemical failures occurred in patients with high-risk disease. All patients are currently alive at the time of this analysis and continue to be followed.ConclusionsA heterogeneous prostate SBRT planning technique with differential treatment volumes (low dose: 36.25 Gy and high-dose: 50 Gy) with a HDAZ provides a safe method of dose-escalation. Favorable rates of biochemical control and acceptably low rates of acute and long-term GU and GI toxicity can be achieved in patients with intermediate- and high-risk prostate cancer treated with SBRT.

Teaser

SBRT has demonstrated promising outcomes for patients with low-risk prostate cancer. In this study, we demonstrate a safe method of dose-escalation to a mean dose of 50 Gy in five fractions for patients with higher risk disease, by using a high-dose avoidance zone (around the urethra, bladder, and rectum). This early experience is associated with high biochemical control rates and acceptably low-rates of treatment-related genitourinary and gastrointestinal toxicity.


from Cancer via ola Kala on Inoreader http://ift.tt/1XbKopo
via IFTTT