Prostate Brachytherapy
  • Advantages of brachytherapy:
    • Convenience
    • Effectiveness
    • Low morbidity
  • Work-Up:
    • History
      • Determine basic urinary function
        • IPSS
    • Physical Exam ( DRE )
      • Clinical Stage
    • PSA
    • TransRectal US Biposy
      • Size, nodule, extra-capsular extension
      • Gleason
      • Number of cores
    • CT or MRI of pelvis to assess pelvic node
  • Indication:
    • In Ontario/Ottawa
      • Low-risk prostate Ca
      • Prostate Volume < ~60cc
        • if volume large can give 3m months of neo-adj hormonal therapy to reduce gland size
    • details of indications!
      • Node Negative
      • Mets Negative
      • T1-T2
  • Contra-indication:
    • Recent TURP
      • higher rate of incontinence
      • also size of cavity makes it very difficult to achieve satisfactory seed placement
    • Large prostate ( > 60cc)
    • Large median lobe
      • why (????should clarify)
    • Pubic arch interface ( > %25 )
    • IPSS > 15
    • High risk / in ON even intermediate risk
      • Some centers for intermediate risk
        • EBRT 45-50Gy —> followed by 110Gy boost ( I-125 ) or 100Gy ( Paladium )
  • Volumes:
    • Prostate + 2-3mm
      • Prostate is contoured with:
        • Transrectal US
        • Patient in lithotomy position
        • Transeverse images taken q5mm
          • from base to apex
          • Images be superimposed and transfered into a dedicated treatment planning system
  • LDR ( low dose rate )
    • Iodine
      • half life —> 60 days
    • Paladium
      • half life —> 17 days
  • Both low energy radiation
    • 23-27KeV
  • Treatment Planning
    • Software receives the images
    • Determine the exact number of seeds and their location which is required to
      • deliver the prescribed minimal peripheral dose to the margins of the target volume
        • Dr Perry: 145Gy to prostate + 3mm margin
          • V150:<67%
          • V200:<33%
          • Rectal dose: 145 Gy to < 2cc rectal wall
          • Urethral dose: <150% of prescribed dose
  • Patient Preparation
    • Enema to clear rectum
    • Anesthesia consult
      • Spinal anesthesia
  • Treatment
    • Positioning
      • Dorsal lithotomy
    • US probe is inserted and attached to a stepper unit and a template for volume study
      • Positioning checked to be identical in pre-treatment position ( for volume study )
    • Distance from bladder base to template is measured
      • This is used as a reference of retraction of the needle tip from the base!
  • Side Effects:
    • GU
      • temporary hematuria
      • urethritis
        • may persist at low level up until 6-8m
      • Acute Retention
        • 15%
        • require catheterisation
        • Majority resume normal function after 10-14days
          • If persist more, surgical intervention should be delayed as long as possible
        • Urethral stricture
          • 4-5%
      • Proctitis
          • 2%
      • Impotency
        • 30%
        • Majority respond to Viagra
        • Amount of ejaculation usually is significantly reduced