Since the discovery of radiation in 1901 radiotherapy has become a key tool for the treatment of cancer. Every year around the world, over 14 million people are diagnosed with cancer according to data from the International Atomic Energy Agency (IAEA). Around half of these patients recieve radiotherapy at some point during their treatment; it is usually combined with other methods such as surgery and chemotherapy.
Cancer is produced when the organism's cells grow and divide in an anomalous and incontrolled way. In radiotherapy, a team of oncologists, physicists, doctors and technicians use a beam with a carefully-measured dose of radiation on the cancerous cells. Depending on the type of cancer and its location, the team must decide between using rexternal radiotherapy via radiation beams or placing radiation sources inside the patient's organism. Radiation harms the DNA of cancerous cells. As they become defective their DNA cannot be repaired, they can no longer divide and grow and eventually die.
The higher the radiation the more cancerous cells are destroyed, but this also means a higher risk for surrounding healthy tissue. For this reason maximum precision is of essential importance in the delimitation of the tumor and the application of the exact radiation doses.
Every year around the world, over 14 million people are diagnosed with cancer according to data from the IAEA
Nowadays, thanks to advances in physics, technology and computer science, and especially thanks to nuclear technology, radiotherapy is much more effective than ever.
According to May Abdel-Wahab, director of the Human Health Division at IAEA,, "these advances may improve the patient's life expectancy during treatment, and in the case of many types of cancer it can also improve the contouring and targeting of the tumor, reduce relapses and increase survival rates".
Tridimensional radiotherapy techniques can already be applied to define where the tumor ends and where the healthy tissue begins
More exact techniques against cancer
Previously, radiotherapy used bidimensional images of tumors, resulting in a lack of precision and danger to surrounding tissues. Thanks to advances in imaging and treatment planning, tridimensional radiotherapy techniques can already be applied to define where the tumor ends and where the healthy tissue begins, thus defining the outline with precision before applying radiation. Thanks to automatic planning instruments, specialists can locate the tumors and plan the exact amount of radiation that must be applied to each part of the tumor and from what angles.
Brachytherapy and SBRT
One of these innovative techniques is tridimensional brachytherapy, a type of internal radiotherapy that uses seeds, bars or capsules with a radiation source. These are introduced in the body near or inside the tumor.
Another even more revolutionary technique is Stereotactic Body Radiation Therapy (SBRT). It consists of obtaining four-dimensional images (height, width, depth and in some cases movement) to radiate from multiple angles, making it possible to apply higher doses with shorter treatments. The patient receives a more effective treatment with less sessions and thus less harmful side effects.
Stereotactic Body Radiation Therapy (SBRT) obtaines four-dimensional images to radiate from multiple angles
"In the case of some types of cancer that cannot be operated on or effectively treated with traditional radiotherapy, SBRT is a new opportunity to lenghten life", indicates Tarek Shouman, Radio Oncology Director at the National Cancer Institute in (NCI) in Egypt.
Dr. Shouman and the NCI team already use SBRT, partly thanks to support from IAEA, to treat lung cancer at its initial stage and recurrent head and neck cancer as well as hepatocellular carcinoma, a type of liver cancer.
Currently, liver cancer is the third cause of death by cancer worldwide. For years, traditional radiotherapy could not successfully treat this type of cancer as it was not possible to administer a second dose of high enough radiation to a liver cancer because of the risks to surrounding healthy tisuses. With SBRT, even small liver cancers can be treated with higher doses of radiation without harming healthy tissue.