Evaluation of Truebeam for Low-Intermediate Risk Prostate Cancer

Prospective Evaluation of Truebeam STX Stereotactic Body Radiosurgery for Low and Intermediate Risk Prostate Cancer

The primary safety purpose of this study is to estimate the rates of immediate and long-term high grade (grade 3-5) gastrointestinal and genitourinary side effects during the five years after TrueBeam stereotactic body radiotherapy in low-risk and intermediate-risk prostate cancer patients. The primary efficacy purpose is to compare 5 year biochemical disease free survival rates with TrueBeam to 5 year biochemical diseases free survival rates with dose-escalated external beam radiation therapy.

The prescribed PTV dose of 36.25Gy shall be given in 5 fractions using the Truebeam STx. At one week after treatment, toxicity and AUA score will be evaluated. At 1 month following treatment, patients will be assessed for acute toxicity, and will fill out AUA form, SF-12, EPIC-26, SHIM and Utilization of Sexual Rx/Devices. At 3, 6, 12, 18, and 24 month intervals (and every 6 months thereafter, through year 5, and annually through year 10, if investigators opt to continue past year 5), patients will be seen and evaluated, including a history, physical exam, ECOG performance status, PSA, toxicity evaluation, and AUA score. In addition, at 6 months, 12 months and annually thereafter, the SF-12, EPIC-26, SHIM and Utilization of Sexual Medications/Devices will be administered. Examination and studies may be done at outside facility. A prostate biopsy will be performed at time of biochemical or local clinical failure, and is encouraged at 2 years following treatment and at time of distant failure.

The study is designed to test the null hypothesis that the acute and late GI/GU toxicity rate 5 years following treatment is greater than 10% versus the alternative hypothesis that the toxicity rate is less than or equal to 10%. The sample size is determined such that there is 90% probability, or power, of identifying excessive toxicity if the true toxicity rate is 20% at the one-sided 5% significance level.

a comparison of biochemical disease free survival in low risk patients treated with TrueBeam compared to (historical) biochemical disease free survival in patients treated with dose-escalated external beam radiation therapy

For the low-risk cohort, the study is powered to compare 5-year bDFS rates observed with TrueBeam STx to 5-year bDFS rates reported with dose-escalated external beam RT. In Beaumont's monotherapy HDR series treating LR patients, 5-yr ASTRO bDFS was 98%; in Demanes' series of 75% LR and 25% IR, this was 96%. Since TB delivers doses similar to HDR monotherapy, a conservative estimate of the success rate for TB is 97.5% for LR patients.

Inclusion Criteria: histologically proven prostate adenocarcinoma within 1 year of enrollment Low risk: Gleason <or=6 & PSA <or=10 & Clinical Stage T1b-T2a,Nx or N0, Mx or M0 Intermediate risk:Gleason <or=6 & PSA<or=10 & Clinical Stage T2b OR Gleason=7 & PSA<or=10 & Clinical Stage T1b-T2b OR Gleason <or=6 & PSA > 10 & < or =20 & Clinical Stage T1b- T2b, Nx or NO, Mx or M0 ECOG Performance Status 0-1 No prior prostate radiation or other definitive therapy Exclusion Criteria: implanted hardware or other material that would prohibit treatment planning or delivery chemotherapy for a malignancy within the previous 5 years history of an invasive malignancy (other than this prostate cancer,or basal or squamous skin cancers) within prior 5 years hormone ablation for 2 months prior to treatment or during treatment

King CR, Lehmann J, Adler JR, Hai J. CyberKnife radiotherapy for localized prostate cancer: rationale and technical feasibility. Technol Cancer Res Treat. 2003 Feb;2(1):25-30. doi: 10.1177/153303460300200104.