Brachytherapy

Brachytherapy (Seeds)

This is the implanting of radioactive pellets or seeds into the prostate. The implantation can be performed as an outpatient stay procedure with the use of I125 or palladium 103 radioactive seeds. Trans rectal ultrasonography guidance is used to insert needles through the perineal skin. Depending on the size of the prostate between 75 and 100 seeds are used. 14-year results have recently been published in America giving a 97% survival rate and a >70% biochemical control rate.

In order to minimise side effects it's important to pick the patients correctly. Patients should have a Gleason score of less than or equal to 6, PSA of less than or equal to 10, a clinical stage of T1C or T2A and no significant previous TURP should have been performed, prostate size must be rendered less than 40 cubic centimetres and urinary symptoms must be mild. In this carefully selected group results are extremely encouraging at 14 years of follow up. Impotence rates are currently being quoted at approximately 50%, which is higher than previously expected. Incontinence is rare as long as a previous TURP has not been performed. Rectal damage is also rare. Its major advantage is that it can deliver a high dose of radiotherapy with minimal side effects. There is an insurance item number and rebate for this procedure. A feeling of burning frequency and urgency may last for up to 6 to 8 months.

Once it has been established that a patient is potentially suitable for brachytherapy, a volume assessment is performed. This involves an ultrasound taking multiple 5 mm step sections of the prostate to get a prolific template of the prostate. This is done under a light anaesthetic and a cystoscopy (examination of the bladder) is performed at the same time. This template will tell the urologist whether a patient is suitable for brachytherapy and also can be used to plan the accurate placement of seeds. If the prostate size and shape is suitable, the medical physicist (Dr Cross) takes this information onto a computer and calculates the correct dosage of radiotherapy required for the prostate. A computer generated plan of where the seeds are to go is then generated. Once payment is received for the seeds, they are purchased from America. There is usually a 2-3 week time lag from the volume assessment to the actual placement of seeds. The seed placement is then done as a day surgery unit procedure and it is important that the bowel has been cleaned correctly the day before the treatment. The treatment takes between 1-2 hours to perform and between 60-120 seeds are inserted into the prostate depending on the size. These seeds are radio-iodine seeds. Most people stay until the next morning and then are fit to go back to work the day after.

Urinary frequency is common for the first 1-12 months and a very small minority have difficulty passing urine. Erectile dysfunction was previously believed to be less common with this technique than any other treatment for localised prostate cancer - more recently however, this has not been the case. If erectile dysfunction does occur, it is always less severe than post-surgical erectile dysfunction. The chance of it occurring varies between 30-50% at 5 years of follow-up. The variation depends on the age of the patient, the dose of radiotherapy delivered and the quality of erections before treatment. Other side effects are rare.

St Vincents Clinic has been performing the procedure since 1996 and have performed over 200 cases with excellent results to date. This is the largest Australian experience. Additionally St. Vincent's has mentored many other centres around Australia.

High Dose Rate Brachytherapy (Wires)

This treatment is also called brachytherapy but involves the placement of wires into the prostate to deliver high doses of radiation directly into the prostate. Three treatments are given over a 36 hour period. This treatment is meant for patients with much more advanced prostate cancer. By delivering a higher dose it is more likely to cure more aggressive cancers than conventional radiotherapy. Furthermore, the accuracy of the planning enables the protection of the bowel from being damaged by the radiation. There is a 5 fold decrease in damage to the rectum compared to conventional radiotherapy doses.

This treatment is always given in association with 4 weeks of external beam radiotherapy. The external beam radiotherapy is generally given two weeks after the completion of the high dose rate brachytherapy.

The typical patient who requires this treatment is a person with a high volume high grade cancer of any age with no major obstruction. It is particularly suitable when local factors mitigate against surgical treatment.

St Vincent's has done the largest series of this technique(over 500 cases)under the guidance of Dr Mark Stevens. Other members of the Department of Radiotherapy and Urology have been integral in this treatment. Major side effects have been exceedingly uncommon with only a 1% chance of major bowel damage. This treatment serves as an excellent option in locally advanced cancers which have not spread to other organs.