Radiation therapy for prostate cancer is administered by our radiation oncology colleagues at BC Cancer Agency. www.bccancer.bc.ca/our-services/services/radiation-therapy
There are two types of radiation treatment available to prostate cancer patients: External Beam Radiotherapy (EBRT) and Brachytherapy.
External Beam Radiotherapy Therapy has been in medically-effective practice for longer than Brachytherapy. This treatment is often simply referred to as Radiotherapy. The goal of treatment is to irradiate a targeted area with as much energy as possible, while avoiding the neighboring organs. Intensity Modulated Radiation Therapy (IMRT), and 3 Dimensional Conformal Radiation Therapy (3D-CRT) are newer versions of EBRT that better achieve this goal. Proton Beam Therapy is becoming a more widely accepted treatment for prostate cancer, while Neutron Beam Therapy is still in the experimental stages.
How Does Radiation Therapy Work On Prostate Cancer?
Radiation is used as a prostate cancer treatment because high energy waves damage the DNA of cells. If a cell divides prior to repairing the damage, the cell will die. Since cancerous cells divide more rapidly than healthy cells, carefully aimed energy will cause their destruction; however, prostate cancer radiation treatment will last over a period of 5 to 9 weeks. During this process, the healthy cells that are repeatedly exposed will be unable to repair the extensive damage. Therefore, the precise aiming of the beam is crucial to the success of the treatment and the avoidance of side effects.
How Do These Radiation Treatments Differ From One Another?
Prostate cancer radiation treatment can be divided into three categories based on the high-energy wave they use: EBRT, IMRT, and 3D-CRT which accelerates subatomic particles called electrons to generate waves of high energy photon radiation. Proton beams use a subatomic particle called protons. Neutron Beam Therapy uses the subatomic particles called neutrons. To continue reading about the different types of subatomic particles, go to the Tools section.
The History Of Radiation Therapy
Prostate cancer radiation treatment has been used in Canada since 1915. The first radiotherapy used radium applicators positioned adjacent to the prostate gland; unfortunately, this technique resulted in significant morbidity. The next technique in radiotherapy used electron beam X-rays; however, these X-rays could not penetrate deeply enough to irradiate the affected tissue. The X-rays were used mainly for palliative care because they also caused skin cancer. After World War II, doctors were able to use megavoltage in prostate cancer treatment. They used radioactive isotopes from Cobalt 60, but by the 1980’s, radiation oncologists began using the linear accelerator, which increased the speed of particles and allowed for the most process aiming of the beam.
Fractionated Prostate Cancer Radiation Treatment
External beam radiation is sometimes called Fractionated, meaning that small doses are given over a long period of time. Patients receive radiotherapy once a day, Monday through Friday over 5-9 weeks, depending on the patient. Normal prostate cells can repair the damage of a small amount of radiation fairly quickly. Cancerous cells cannot. Receiving a small dose everyday helps to minimize the damage sustained by the healthy cells of the surrounding organs. Giving patients the weekend off helps their body to recover enough to withstand the next five days of treatment.