External Beam Radiation Prostate Cancer Treatment
Following the same general idea of prostate seed implant treatment, external beam radiation focuses on delivering radioactive waves to hinder and destroy prostate cancer cells. However, instead of treating the prostate from within, external beam radiation uses high energy rays targeted directly to the affected area. Normally, this is delivered via extremely potent energy beams, like X-rays or protons.
There are a few instances where this therapy is used. It can be used as the main form of prostate cancer treatment for the early stages of cancer, particularly when it’s confined to the prostate gland. In addition, it is commonly used in conjunction with hormone therapy if the cancer is more developed but still localized to just the prostate. External beam radiation is also used post-surgery to help prevent a recurrence of the disease, either as a precaution (called adjuvant therapy) or if PSA levels increase post-surgery. Lastly, this treatment can be used to alleviate symptoms if cancer has advanced beyond the prostate gland.
Two major protocols exist for this kind of therapy. The first is called 3D conformal radiotherapy, abbreviated as 3D-CRT. Using pre-treatment scans, the beams are specifically targeted for each patient, taking into account the size, shape, and location of the gland. The beam then aims specifically for the affected areas with a consistent strength of radiation.
Growing in popularity is the Intensity-Modulated Radiotherapy, abbreviated IMRT. Similarly, to 3D-CRT, computer programs map the affected areas of the prostate from scans performed in a preparation session. The machine itself then takes these scans and delivers targeted radiation with varying amounts of strength to the affected parts of the prostate. The ability to control directly the amount of radiation each part of the prostate gets reduces the amount of damage to surrounding, healthy tissue which has a positive effect in reducing side effects. For this type of therapy to be the most successful, images of the prostate are taken at every session, to help ensure the treatment is as accurate as possible.
Treatment is generally performed over several weeks, including some preparatory treatment. Prior to the first appointment, a radiologist will insert marker seeds for the mapping of the prostate. In addition, there will normally be radiation simulation treatments, which help figure out a comfortable position for the treatment itself because it is particularly important for a patient to stay still during the procedure.
Advantages of External Beam Radiation
- For cancer located solely within the prostate, external beam radiation has a decent chance of eliminating the cancer.
- The procedure and treatments are relatively non-invasive. During the radiation therapy itself, a patient is asked to lie still while a machine called a linear accelerator delivers the radiation to the targeted areas. In some instances, a patient may be fitted to a customized immobilization set up to help keep the patient still.
- Treatments themselves are relatively short, lasting only about 10 minutes. Including preparation time, the outpatient procedure takes generally less than an hour.
- Patients can generally resume their usual daily activities, including going to work immediately.
- Can be used in conjunction with other therapies, particularly hormone therapy, to achieve greater results
- Treatment is considered pain free by almost all patients.
Disadvantages of External Beam Radiation
- External beam radiation is time-intensive, requiring treatment five days a week for several weeks. If the treatment clinic is far away, this can be inconvenient.
- For treatments, some patients need to have empty bowels. This may mean that a patient is given a laxative, which some find inconvenient.
- Compared to brachytherapy, there are higher rates of side effects from external beam radiation, particularly in terms of erectile dysfunction and urinary issues. Normally, these side effects can be eliminated or alleviated by medications.
- Radiation prior to surgery can make surgery no longer viable due to damage to the prostate and surrounding areas.