CyberKnife Dose Escalation Prostate Cancer Trial — CK-DESPOT  

Prostate Cancer Clinical Trial

Official title: CyberKnife Dose Escalation for Unfavorable and High-risk Prostate Cancer

Status Recruiting

Clinical Trial Summary

Stereotactic body radiation therapy (SBRT) has been employed in the treatment of prostate cancer. Multiple single institution experiences suggest high biochemical control rates with acceptable toxicity in low risk prostate cancer but efficacy data in unfavorable type prostate cancer is less convincing. CyberKnife-SBRT (CK-SBRT) can be used to escalate radiation dose delivery to the prostate while sparing normal tissue.

Clinical Trial Description

The optimal radiation schedule for the curative treatment of prostate cancer remains unknown. Prostate cancer patients receiving radiation therapy are typically treated 5 days per week for 8-9 weeks. Recent data suggest that large radiation fraction sizes are radio-biologically favorable over lower fraction sizes in prostate cancer radiotherapy. The sensitivity of a tumor or normal tissue to fraction size of radiation can be approximated by the alpha-beta ratio. It has been suggested that the alpha/beta ratio for prostate cancer is actually as low as 1.5 implying that the current radiation therapy paradigm for prostate cancer treatment might be fundamentally flawed, as high fraction sizes would be expected to damage tumor more readily.

Typical prostate SBRT doses do not appear to have similar efficacy in higher risk prostate cancer suggesting even higher doses are required. Many techniques including dose escalated external beam radiation therapy (EBRT), proton therapy (PT) and brachytherapy have been employed to increase dose to the prostate. Data from the ASCEND-RT trial utilizing low dose rate brachytherapy boost showed a dramatic 21% improvement in biochemical control at 9 years favoring brachytherapy boost compared to conventional dose escalated EBRT radiation therapy. However, no corresponding benefit was identified in overall survival, incidence of bone metastases or prostate cancer specific mortality while a 3 fold increase in late urinary toxicity was noted.

SBRT is well tolerated with minimal acute and late side effects. In this protocol, CK-SBRT will be used to target the microscopic and gross disease in the prostate, seminal vesicles. An escalated dose of 40 Gy in 5 fractions will be delivered to the entire target volume while any nodules visible within the prostate gland on endorectal MRI will receive 50 Gy in 5 fractions. ;

Related Conditions & MeSH terms

• Prostate Adenocarcinoma
• Prostate Cancer
• Prostate Neoplasm
• Prostatic Neoplasms

• NCT number: NCT03822494
• Study type: Interventional
• Source: Crozer-Keystone Health System
• Contact: Rachelle Lanciano, MD
• Phone: 610-446-6850
• Email: rachelle.lanciano@crozer.org
• Status: Recruiting
• Phase: N/A
• Start date: July 12, 2018
• Completion date: July 12, 2028