To download and print a PDF version of this document, click here LDR Brachytherapy.pdf

Low dose rate prostate brachytherapy (LDR) treatment involves permanently implanting tiny radioactive seeds directly into the diseased prostate - killing the growing cancer cells by damaging their ability to divide and grow.

The radioactive seeds are less than 5mm long and 1mm in diameter. They are made from radioactive iodine (I125) and are encapsulated in titanium. Using sophisticated ultrasound and computer technology, between 70 and 120 radioactive seeds are inserted into the prostate. Unlike conventional external beam radiotherapy where the radiotherapy beams travel through the body’s tissues to get to the prostate, the configuration of the seeds placed during brachytherapy, creates a high field of radiation that is essentially totally confined to the prostate.

The radiation given off by the seeds decreases or “decays” over several months and reduces at a rate of 50% each 59 days. By 6 months, 85% of the radiation has been delivered and by 12 months almost 100% of the radiation dose has been delivered to the prostate gland and the seeds are biologically inactive. The inactive seeds remain in the prostate forever.

Who is suitable for Low Dose Rate Brachytherapy?

Patients with low to intermediate risk localised prostate cancer are suitable for low dose rate brachytherapy. To be eligible for a Medicare rebate, patients must meet the following criteria;

• PSA ≤ 10 at the time of diagnosis
• Gleason score ≤ 7
• Clinical stage ≤ ct2b

In addition, there are other criteria that patients must satisfy to be suitable. These criteria are not hard and fast and there is some leeway in these criteria.

• Prostate volume < than 45 mls. Larger prostates can cause technical problems with insertion of the radio active seeds. Patients with prostate volumes up to approximately 65mls can occasionally be treated after reducing the size of the prostate with medications.
• IPSS (international prostate symptom score) score < 15 (men must not have difficulty in passing urine)
• UFR (urinary flow rate) > 15 mls per second
• Patients must not have had a prior TURP
• Patients must not have a large middle lobe of the prostate (detected on cystoscopy)

Low dose rate brachytherapy has a proven track record over 13-15 years and after this time the results are not defined. As a general rule, low dose rate brachytherapy is considered for men with a life expectancy of a minimum of 13-15 years ie. from the age of 62 onwards. In special circumstances, younger men can be considered for low dose rate brachytherapy.