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Ultrasound Therapy for Early Stage Prostate Cancer
Ultrasound treatment for prostate cancer is a new therapy that aims to destroy cancer cells in a minimally invasive manner. The procedure is commonly known as high intensity focused ultrasound (HIFU). It makes use of ultrasound energy to generate rapid heat that is concentrated on the affected area in order to burn out the cancerous tissue. The ultrasound technology helps to create a sharp focus on the target area, and the temperature can be elevated rapidly to 90 degrees C (194 degrees F) within a few seconds.
The ultrasound machine delivers a high intensity stream of sound waves to the target area. The procedure had been originally developed to treat benign prostatic hyperplasia, but now doctors are evaluating its effectiveness in destroying prostate cancer cells. Ultrasound is non-ionizing in character, unlike radiation which is ionizing and results in peripheral damage to the healthy tissue. The HIFU beam delivered by the ultrasound method does not harm the healthy tissue that comes in its path during entry and exit.
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Advantages of Ultrasound Therapy
The key benefit of ultrasound treatment for prostate cancer is that the patient does not have to suffer from too many adverse side effects. The therapy only makes use of sound waves to destroy cancer cells, which do not cause any substantive harm to the healthy tissue that may come in the path of the beam. The effectiveness of ultrasound to eliminate prostate cancer is a subject of ongoing research, but scientists are hopeful of achieving more success with this therapy. Clinical trials for this therapy have been conducted in Europe and China extensively. The US Food and Drug Administration also approved HIFU clinical trials in 2008 for recurrent prostate cancer.
Medical researchers are also evaluating the benefits of applying this treatment for such prostate cancer patients who are unable to have surgery. At present, the benefit of this treatment is only limited to removing smaller sized prostate tumors, or partial reduction of a large sized tumor of the prostate. However, if the tumor has already metastasized to other parts of the body, ultrasound therapy may not be useful to treat such condition. HIFU cannot be transmitted through air or through solid bone, which limits the type of cancers that may be treated with this therapy. HIFU may also be used as a salvage therapy after radiation for prostate cancer.
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How is the HIFU Treatment Delivered to the Prostate?
The prostate is located deep within the pelvis. Therefore, the best way to deliver HIFU to the target area within the prostate is by inserting a transrectal probe into the patient’s rectum. This position makes it possible to send sound beams directly to the affected area with greater precision. The high intensity beams that are generally used are in the range of 100 watts/pulse. The cell destruction is achieved thermally with this mechanism, as against mechanical forces or cavitation. The delivery of the energy dose takes place in less than a second, and it occurs in a highly controlled and well defined manner.
The results of clinical trials with this delivery mechanism have been quite encouraging till now. There are indications that HIFU may be able to achieve the same kind of success in removal of cancer cells as may be achieved with prostate surgery or radiation therapy. However, the long-term effects of this therapy are not yet clear. In both the United States and the UK, this treatment for prostate cancer is only being used as part of clinical trials.