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Localised Prostate Cancer: New Treatment In Combination With Radiotherapy Beneficial, Says Study

Researchers at Queen's University Belfast have developed a new treatment to be used in combination with radiotherapy that could significantly improve treatment outcomes for men with locally advanced prostate cancer. The treatment can make cancerous cells up to 30 per cent more receptive to radiotherapy while simultaneously reducing adverse side effects that limit the quality of life [1].

Radiotherapy is extensively used to treat various localised cancers including prostate cancer, offering the best chance for curative intervention. However, approximately 30 per cent of prostate cancer patients experience treatment failure leading to disease progression.

The research team at Queen's have developed a new nanomedicine comprised of tiny gold particles, coated in a small peptide called RALA. If these nanoparticles are present in tumour cells when treated with radiotherapy, they increase the cell-killing potential of this conventional treatment, helping to reduce the risk of disease relapse. In the absence of radiation, the gold nanoparticles are not directly toxic, meaning that the risk of treatment-related toxicity is low [2].

What Is A Nanomedicine?

Nanomedicine is a medical application of nanotechnology. Nanomedicine covers a wide spectrum of applications from nanomaterials and biological devices to nanoelectronic biosensors and even future applications such as biological machines that could use molecular nanotechnology [3].

Various groups around the world have reported that gold nanoparticles, or other high atomic number elements, hold the potential to sensitise tumour cells to radiation treatment, but one key challenge has been delivering these particles in sufficient levels to the right regions within the tumour cells. Combining the gold particles with RALA increases the efficiency of nanoparticle uptake, while also enabling the gold particles to be delivered to regions within the cells that are more sensitive to the effects of radiation damage.

What Is Localised Prostate Cancer?

Cancer that is confined to the prostate and has not spread to other parts of the body is called localised prostate cancer. This type of prostate cancer may also be called early or organ-confined prostate cancer, or prostate cancer of stage T1 or T2.

According to physicians, prostate cancer can be classified as localised, locally advanced, or advanced. Cancer that is located completely inside the prostate gland is termed localised prostate cancer [4].

Generally, localised prostate cancer does not grow or grow very slowly and is not likely to spread. As a result, you may never experience any problems or experience any reduction in your life expectancy. Accordingly, localised prostate cancer might not require treatment. You might be able to have your cancer monitored through regular check-ups instead to ensure cancer does not progress more quickly than expected.

What Are The Study Findings?

The study, published in Nanobiotechnology, shows that through the new formulation, prostate cancer cells were rendered up to 30 per cent more sensitive to the cell-killing effects of the same radiotherapy used to treat patients. Furthermore, in experiments investigating the magnitude of effect in small 3-dimensional models of prostate tumours called tumour spheres, the combination of radiation and RALA-gold nanoparticles completely suppressed tumour sphere growth.

Professor Helen McCarthy, from the School of Pharmacy at Queen's University Belfast, explains: "The peptide enables the gold nanoparticles to be delivered more efficiently to the tumour cells. The gold then interacts with the radiotherapy, increasing the cell-killing effect in a highly localised manner."

The gold particles are up to three times more visible on standard medical imaging equipment. This means that if the nanoparticles are located within the tumour, they should help to improve the accuracy of radiotherapy delivery, reducing the risk of off-target damage to neighbouring normal tissue such as the bladder or bowel.

The multi-disciplinary team have recently been awarded £376,000 from Prostate Cancer UK to evaluate the effectiveness of these implants at increasing the sensitivity of prostate cancer cells to radiotherapy.

Dr Jonathan Coulter, from the School of Pharmacy at Queen's University Belfast, explains: "Our research has shown that ultra-low concentrations of the RALA-gold nanoparticles effectively sensitise prostate tumour cells to radiotherapy. Now we want to build on this work, to address the second major challenge, consistently delivering sufficient nanoparticles to the tumour throughout a patients' radiotherapy. We are delighted that Prostate Cancer UK is supporting our proposal to develop a biodegradable implant designed to provide sustained release of the gold nanoparticles."

"Following insertion into the main tumour lesion, the biodegradable implant will consistently release the nanoparticles over time. This is opposed to current approaches that involve daily injections. Following consultation with a local prostate cancer patient focus group, we learned that a one-off implant would be better tolerated by patients than regular injections to the tumour."

Who Are At The Risk Of Developing Localised Prostate Cancer?

Localised prostate cancer is divided into three risk groups according to the likelihood of the disease growing rapidly or spreading [5].

These factors determine your risk group:

  • Size of the tumour (stage T)
  • The cell appearance under a microscope (the grade) and The pattern of cells in the prostate tissue (this is called the Gleason score) are both taken into consideration.
  • Your prostate-specific antigen (PSA) blood test

Low-risk prostate cancer

Low-risk prostate cancers are unlikely to spread or grow for many years to come. The following characteristics indicate that you have low-risk cancer:

  • a T stage of T1 to T2a
  • a Gleason score no higher than 6
  • a PSA level less than 10 ng per ml (ng/ml)

Medium (intermediate) risk prostate cancers

A cancer of medium (intermediate) risk is unlikely to grow or spread for a few years. If you have the following characteristics, your cancer is of medium risk.

  • a T stage of T2b
  • a Gleason score of 7
  • a PSA level between 10 and 20 ng/ml

High-risk prostate cancer

High-risk cancers might grow or spread within a few years. Localized prostate cancer is considered to be high risk if you have any of the following characteristics:

  • a T stage of T2c
  • a Gleason score between 8 and 10
  • a PSA level higher than 20 ng/ml

High risk localised prostate cancer is also locally advanced prostate cancer. This means that your doctor may describe your cancer as locally advanced, even if it is contained within the prostate gland.