Slow accrual

This is a dose finding Phase I/II study of combined focused LDR brachytherapy boost with whole gland single fraction HDR for men with low and intermediate risk prostate cancer and Dominant Intraprostatic Lesion (DIL) visible on multi parametric MRI. Patients will receive 19 Gy HDR to the whole gland with concurrent LDR brachytherapy boost to the DIL, in a sequential dose escalation manner. Primary endpoints are early toxicity.

Eligible patients will have low and intermediate risk prostate cancer with a dominant intraprostatic lesion definable on multi parametric MRI (PIRADS 4 or 5). Patients will have MR planned LDR focal brachytherapy to the DIL using iodine-125, while at the same time have single 19 Gy delivered to the whole prostate using ultrasound directed high dose-rate brachytherapy (HDR). The LDR boost dose will start at 50 Gy, and increase DIL dose in sequential cohorts of patients up until a dose of 80 Gy. Up to 20 patients will be included. Primary endpoint is toxicity at 3 months.

Inclusion Criteria:

• Confirmed Adenocarcinoma of the prostate
• Single PIRADS 4 or 5 lesion on multiparametric MRI
• T1c-T2b on rectal exam
• Gleason 3+3 and PSA < 20ng/mL
• Gleason 3+4 and PSA <10ng/mL
• Less than 50% of the cores positive in an untargeted prostate biopsy.
• Prostate volume < 60 cc

Exclusion Criteria:

• Incapable or ineligible for MRI imaging
• Previous trans-urethral resection of prostate (TURP)
• Previous or current use of androgen deprivation
• Baseline International Prostate Symptom Score (IPSS) > 15
• Evidence of distant or nodal metastasis
• Disease that contraindicates treatment with radiation (e.g connective tissue disease)
• Unsuitable for anesthesia due to comorbidity