External beam radiation doesn't at all times kill prostate cancer. Researchers estimate that roughly 20% to 30% of patients experience a rising prostate-specific antigen (PSA) or biochemical reoccurrence of their disease after treatment. Debate has raged about which secondary, or salvage, treatment needs to be attempted.
High-intensity focused ultrasound (HIFU), which uses sound waves to destroy cancerous tissue, is an option for treating local reoccurrence (see Figure 1 below). Because each pulse of energy destroys only a small amount of tissue, doctors can goal certain areas and spare others, theoretically reducing the possibility of uncomfortable side effects.
Figure 1: High Intensity Focused Ultrasound (HIFU)During HIFU, pulses of energy generated by a rectal probe destroy tissue at the purpose where the sound waves meet. Because the technology can goal certain areas and spare others, uncomfortable side effects could be minimized. |
British researchers recently evaluated the effectiveness of HIFU in 31 men who experienced biochemical reoccurrence of prostate cancer after external beam radiation. Before HIFU, the common PSA in men was 7.7 ng/ml. Three months after HIFU, roughly 65% ​​had a PSA of 0.2 ng/ml or less. About half of those that reached the six- and nine-month checkups maintained PSA at this level.
Side effects of HIFU include narrowing of the urethra and the necessity for procedures to remove dead tissue, urinary tract infections, painful urination, urinary incontinence, and, rarely, rectal and urethral strictures. Includes making a hole in between. The potential for uncomfortable side effects was just like that of other preventive treatments, making HIFU a seemingly viable option.
The researchers noted that choosing patients suitable for sparing HIFU is the most important challenge. HIFU is not going to effectively treat metastatic cancer, but some patients have cancer that has spread elsewhere within the body and escaped detection before HIFU.
Source: Zakrakis E, Ahmed HU, Ishaq A, et al. Feasibility and safety of high-intensity focused ultrasound as salvage therapy for recurrent prostate cancer after external beam radiation therapy. BJU International 2008; 102:786–92. PMID: 18564135.
Originally published on April 1, 2009. Last reviewed on March 31, 2011.