Targeted prostate cancer treatment hopes to minimise side effects

The Icon Cancer Centres in Victoria are using focal low dose rate (LDR) brachytherapy to provide highly targeted radiation for prostate cancer.

The data is being collected as a part of the LIBERATE registry, examining oncologic outcomes and the possible reduction of the side effects such as erectile dysfunction, which are present in other treatments.

While LDR brachytherapy has been a standard treatment option for some years, and offers a similar side effect profile compared to external beam radiation and surgery, the newer focal approach is designed to target the cancer more closely.

The focal treatment is said to be suitable for about 15–25% of prostate cancers that are confined to one area of the prostate and assessed on biopsy as low to intermediate risk.

A targeted approach

Dr Andrew See, radiation oncologist at Icon Cancer Centres and co-lead of the LIBERATE registry, said, “Because of advances in diagnostics and imaging, we now have an unprecedented level of understanding of where the cancer is within the prostate, like having precise GPS coordinates. We can go in with a very targeted approach just to treat that geographic area with a small margin.

“We’re treating only about 20% of the prostate using the brachytherapy seeds, instead of all of it, and you’re getting rid of the cancer with a 15-minute outpatient procedure, which is like a haircut, but you’re leaving 80% of their prostate untouched. Doing this minimises the risks of erectile dysfunction, urinary incontinence and bowel injury.”

Focal LDR brachytherapy treatment involves radioactive seeds being inserted into the prostate to deliver radiation directly to cancer cells, while minimising damage to the surrounding healthy tissue.

Studies into the procedure to insert the seeds have shown it is comparatively quicker, less invasive and with a decreased likelihood of ongoing side effects, such as urinary incontinence and erectile dysfunction, than surgery or external beam radiation.¹

See said, “All prostate cancer treatments come with some level of risk. With active surveillance men can feel a psychological burden of knowing they have cancer, and the ongoing testing can be fatiguing, even when their cancer is not symptomatic.

“We are always looking at how we can kill the cancer whilst reducing risks and side effects for patients.”

Brachytherapy seeds emit radiation for three months, with the cancer being destroyed during this time. The seeds then become inert and do not need to be removed.

Additional advantages

Focal LDR brachytherapy is said to have additional clinical advantage for patients should another prostate cancer be found later in life, with other treatment options remaining available.

“If a new cancer appears on the other side of the prostate, the patient can still have surgery if needed. Successful treatment via focal brachytherapy doesn’t prevent a new cancer occurring later on. We know from surgeon feedback that there is no issue removing the prostate if this occurs, and for those few patients we have still given them perhaps several years with their prostate and without issues of incontinence and sexual dysfunction that could occur from standard treatments of the whole gland,” See said.

So far, 110 men have contributed their data to the registry. See said early results are promising but they will have to wait some years for long-term data.

“The sense is that morbidity is definitely less, and tolerance is much better. Early oncological outcomes are still a few years off, but there’s been no reason not to be positive,” See said.

The importance of early detection

According to the Australian Institute of Health and Welfare², prostate cancer is estimated to be the most commonly diagnosed cancer for males and for Australia overall in 2023, with an estimated total of 25,500 cases.

The majority of prostate cancers are diagnosed at stage I or stage II, and early-stage localised prostate cancer is most suitable for focal LDR brachytherapy.

Focal LDR brachytherapy treatment is available at Icon Cancer Centres located in Epworth hospitals in Geelong, Richmond and at Epworth Freemasons in East Melbourne.

See is co-leading the LIBERATE registry with urologist colleague Associate Professor Jeremy Grummet. He said, “As a surgeon, I also treat more aggressive prostate cancers with robotic prostatectomy, so I see the typical side effects our standard treatments so often cause. But seeing our patients after focal brachytherapy and their lack of side effects, it’s like chalk and cheese. As our study’s name implies, we are really trying to “liberate” prostate cancer patients from the burden of treatment side effects.”

Grummet, however, also stressed the importance of early detection. “Focal LDR brachytherapy is most suited to men whose prostate cancer is low–intermediate risk and these men are most likely to be asymptomatic. This highlights the importance of early detection,” he said.

It is recommended that men aged 50 and over or aged 40 and over with a family history of prostate cancer consider prostate specific antigen (PSA) testing.

<sup>1. https://bjui-journals.onlinelibrary.wiley.com/doi/full/10.1111/bju.13252
2. https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/overview-of-cancer-in-australia-2023</sup>

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