When for the first time on 27th April 2015 the news of developing innovative 3D-printed shields for prostate cancer radiotherapy was published on the internet, the importance of radiotherapy was once again highlighted. Radiotherapy along with surgery and chemotherapy are the three pillars of cancer treatment. Nearly two-thirds of cancer patients receive radiotherapy. The first radiotherapy was done only thirty years after the discovery of X-rays by Wilhelm Roentgen (1845-1923). Emil Grubbe was a medical student who convinced one of his professors to perform radiotherapy for a woman who no longer responded to medical treatment for breast cancer. He became the first radiation oncologist. In a few years radiotherapy spread first in the United States and Europe and then worldwide. The biggest complication of conventional radiation therapy is that it does not discriminate between healthy and cancerous cells. Thus for tumours that are deep inside the body, radiation therapy often yields poor results, while destroying lots of normal cells and tissues. Radiotherapy has many side effects such as sore skin or peeling, tiredness, nausea, loss of appetite, diarrhoea, hair loss, effect on fertility, stiff joints and muscles.
While in conventional radiotherapy the X-rays or other rays are usually made artificially through specific tubes, there are also some certain atoms which naturally emit radiation. These atoms are called radioactive atoms, i.e. polonium, Radium, iodine-125 and palladium-131. Many early advocates of Radiation Therapy in the 1920s had relied on the placement of radioactive sources in close proximity or even within the tumour, a technique known as brachytherapy. In many tumours, for example cervical and uterine cancers, brachytherapy became the backbone of treatment and remains so today.
Now prostate cancer is the first in line to be a target for radioactive atoms. At a meeting of the European Society for Radiotherapy and Oncology in Spain, researchers from the Vancouver Cancer Centre reportedthat patients undergoing low-dose-rate prostate brachytherapy via implanted radioactive “seeds” survived twice as long as those undergoing conventional high-dose radiotherapy.
The Canadian team performed a study involving 398 men diagnosed with prostate cancer who had no metastasis but were considered to be resistant to conventional therapies. In this method, seeds of radioactive atoms were implanted near the prostate tumour. Prostate cancer is the most common cancer affecting men, developing primarily in those over the age of 50. In 2012 there were 1.1 million reported cases with 307,000 deaths worldwide.
According to James Morris, who led the Vancouver study, brachytherapy is a highly cost-effective method, even though it requires long training and much experience to produce consistent results. The Canadian study with radioactive seeds is a promising cause of treatment, but so far it has only been tested on a small number of participants. Even though in brachytherapy the source of radioactivity is close to the tumour and low doses can be used, these seeds still release radiation in all directions. For example brachytherapy of the prostate may induce rectal inflammation and bleeding, narrowing of the urine passage and erection problems. So, for many decades, cancer research has been focused on finding more selective treatments.
Scientists have been looking for a way to localise the radiation on the target tumour and decrease the amount of radiation received by healthy cells. Different materials and technologies have been tested. Today it seems that 3D printing, has come to the rescue. Innovative 3D printers provide the opportunity of building delicate tiny shapes almost from all kinds of material.
Researchers at Louisiana Tech University and University of Mississippi Medical Centre have presented a simple solution by using innovative protective shields. They created customisable 3D-printed shields for low-dose-rate radioactive seeds from a combination of plastic forming raw material and Barium Sulphate. Barium Sulphate is not only compatible with human body cells and tissues, it is also a good compound for stopping radiation. The shield was implanted along with the radioactive seeds containing one of three types of radioactive atoms: Iodine, Cesium or Palladium. Applying 25% Barium Sulphate in the shield reduces the amount of radiation in unwanted directions from 76% to 93%.
X-rays are generally known as the rays used in radiology. The kind of X-rays which are used in radiology are low – energy X-rays that create images. Radiation therapy uses high-energy X-rays to treat patients. Radiation therapy uses high-energy particles or waves, such as X-rays, gamma rays, electron beams, or protons, to destroy or damage cancer cells. Other names for radiation therapy are radiotherapy, irradiation, or X-ray therapy. A patient may receive radiation therapy before, during, or after surgery, depending on the type of cancer being treated. Some patients receive radiation therapy alone, and some receive radiation therapy in combination with chemotherapy.
The global market for brachytherapy was estimated at $680 million in 2013 and is set to rise to $2.4 billion by 2020, according to an industry analysis by MEDraysintell (medical radiation strategic intelligence experts).
Radioactive atoms are also used in other ways for treating cancer. For example radioactive Iodine (Iodine – 131) is used for treating thyroid cancer. The thyroid gland absorbs nearly all the Iodine in the body. When radioactive Iodine is consumed orally (liquid or capsule form), it concentrates in the thyroid cells. The radiation emitted from Iodine atoms will destroy thyroid cells as well as cancerous cells with the least effect on the rest of the body cells. This method of treatment is an optional therapy for removal of any thyroid tissue not removed by surgery and for cases where cancer has spread to other nearby tissues. Another example is radioactive phosphorus injection for treating some blood disorders like PCRV (polycythaemia rubra vera) when the bone marrow makes too many red blood cells, platelets and white blood cells.
The new therapy method of applying a protective shield along with a radioactive source is still only proof-of-concept and is yet to be tested in humans. However, at least for people with prostate cancer, brachytherapy research seems to be pointing in the right direction.