Last updated May 24, 2017 at 10:44 am
Cancer poses a significant threat to thousands of people within the Australian community, with over 130,000 new cases of cancer-afflicted patients predicted here in 2017. For over a century now, tumours have been treated with radiotherapy – a method using specialised equipment to blast cancerous tissues with radiation.
Typically, ‘external beam radiotherapy’ (irradiation from sources outside of the patient’s body) is used to treat cancerous tumours throughout the body. Though this is mainly performed in two different ways – using either photons (X-Rays) or protons – the basic biological effects are, for the most part, the same: energy is delivered to cancerous tumours, the DNA of the rogue cancerous cells is damaged, the cells fail to replicate, and therefore they die off and the tumour recedes. However, there are several differences between these approaches.
Conventional radiotherapy uses a beam of X-Rays produced from a linear accelerator that uses electricity to form a sub-atomic particle beam to be used as the source of high-energy radiation for treatment. The source of radiation is delivered at the surface of the body and penetrates through the patient – including the area in front of, and behind, the target tumour. Though very effective, conventional external radiotherapy can be difficult to perform when malignant tumours are close to vital organs as radiation can progress past the original tumour and through to the other side of a patient’s body.
Despite the use of strict intensity modulation, this form of conventional radiotherapy inevitably results in damage to the tissues surrounding cancerous tumours, and can result in additional complications. For example, photon radiotherapy of tumours in close proximity to a vital organ such as the heart can lead to heart failure. This poses a major concern for patients who are already at a significant health risk. A newer technology has been designed specifically to target tumours via external treatment while reducing the potential of adverse effects in the surrounding tissues, and this is where proton radiotherapy comes into play.
Proton Beam Therapy (PBT) for the treatment of cancer was first proposed in 1946 and involves depositing positively charged subatomic particles called protons into targeted tumours, where they deliver their radiation to destroy cancerous cells. For this process, protons are sped up in a cyclic high frequency accelerator which utilises an electromagnet with a high frequency alternating voltage to move protons in a spiral that increases their speed. When protons reach the required speed they are deflected by magnets to produce a high-energy beam, the energy of which is determined by the speed that the particles have been accelerated to – the higher the energy of the beam, the further into the body it can travel.
Though PBT delivers radiation to the healthy tissue in front of the tumour, the tumour takes in approximately 80% of the energy from the beam, leaving the area behind the tumour unharmed. This provides a distinct advantage over conventional radiotherapy, as surrounding tissue remains unaffected by the harmful radiation, meaning that PBT can be used to reliably treat several cancers close to vital organs or tissues, such as; central nervous system cancers, eye cancer, head and neck cancer, liver cancer, and prostate cancer, as well as noncancerous brain tumours. Additionally, this means that patients have a significantly reduced recovery time, a reduced risk of developing secondary tumours as a result of radiation exposure, as well as a higher probability of tumour eradication and therefore survival.
Proton beams treat malignant tumours in areas where conventional radiotherapy would put patients at risk of adverse side effects. By ensuring that the majority of high-energy radiation is delivered to the site of the tumour, Proton Beam Therapy results in eradication of tumours with a reduced risk of damaging surrounding tissues. Source: http://www.proton-cancer-treatment.com/proton-therapy/advantages-of-proton-therapy/
Radiotherapy is widely accessible in Australia, and a wide range of cancers are able to be treated via local methods available. However, at present PBT is not available in Australia and, while Australians requiring therapy may apply for funding from the Federal Government, patients are required to fork out up to $200,000 in order to be treated in overseas facilities. Despite this, some very positive news has come out in the past week regarding PBT in Australia – although they are currently unavailable Down Under, the 2017 federal budget has a large sum of money earmarked for the implementation of these technologies within Australia. This will see a new facility built in Adelaide that is slated to be a 14-floor building totalling 21,000 square meters, with three floors dedicated to the PBT facility, while the rest of the space will be used for dry lab research on the therapy, 10 clinical trial rooms and the potential for industry to establish within the precinct. The new facility will be fully operational by 2020 and serve as a beacon of hope for all Australian’s suffering from difficult-to-treat-cancers, as well as provide the research required to make PBT technology widely available throughout Australia.