Brachytherapy is a form of radiation therapy where the radiation source is delivered directly into or next to the target tissue.
Low dose rate (LDR) brachytherapy
Radioactive seeds directly implanted into the prostate.
Most commonly used Iodine-125, but can use Palladium or Cesium.
Delivers a lower dose rate but radiation is delivered over weeks-months, resulting in a higher total dose – at least 100 Gy (EAU suggests total dose (D90) > 140 Gy leads to higher biochemical control rate)
EAU suggests can be combined with EBRT for intermediate-high risk disease with slight improvement in disease control but higher toxicity rates.
May pass seeds in urine or ejaculate post procedure. No baby on lap, wear condoms for first few ejaculations.
Eligibility:
- Low or favourable-intermediate risk (ISUP grade 1 or 2) organ confined disease
- < one third of cores ISUP 2
- IPSS 12 or less
- QMax 15 or greater
- Prostate volume no greater than 50 – 60 cc
- No middle lobe
- No previous TURP
- No contra-indications to radiation – previous radiation, rectal inflammatory bowel disease
Other considerations – need to be able to place in lithotomy, no pubic arch interference, need to be able to have TRUS and anaesthetic.
Efficacy
No RCT comparing LDR brachytherapy to radical prostatectomy.
Large population cohorts show good biochemical disease-free rates at 10 years, comparable to surgery
However, these are only in low-risk cohorts, who will have favourable outcomes regardless of treatment (and generally contemporaneously managed with surveillance).
Side effects of brachytherapy
- Urinary incontinence – about 7 %, up to 30 % with TURP before or after
- Urinary retention (up to 15 %)
- Perineal pain and haematoma rare
- Urethral stricture
- Rectal irritation and rectal frequency, radiation proctitis (less than EBRT)
- Erectile dysfunction – after a few years
- Seed migration
- Rectourethral fistula (beware endoscopists doing rectal biopsies)
- Radiation cystitis and haematuria
- Secondary malignancy
| Pros | Cons |
| Less toxicity (incontinence, ED) cf. surgery, esp early
Day case (cf. EBRT)
Less invasive cf. surgery
Good cancer control for low risk disease
Higher dose to prostate cf. EBRT
Less effect on surrounding tissues cf. EBRT
|
Limited availability / need subspecialist rad onc and urologist
Not suited to all prostates
Long term side effects as above
Likely inferior cancer control for intermediate/higher risk disease
PSA bounce / more difficult to monitor treatment response
Difficulty of salvage treatment if local recurrence
|
High dose rate (HDR) brachytherapy
HDR brachytherapy uses radioactive ‘rods’ or cannulas inserted into the prostate temporarily to allow delivery of Iridium 192 over 1 – 2 days.
Delivered at a higher dose rate with radiation delivered over a couple of minutes, at a total lower dose cf. LDR
12 – 20 Gy in 2 – 4 fractions – about 80 Gy total but not directly comparable due to fractionation.
Can be combined with EBRT, especially in locally advanced high risk disease.
Treatment regimes vary between centres, and therefore medium to long term evidence for cancer control rates is limited.
