High-Intensity Focused Ultrasound (HIFU) is a non-invasive medical technology for treating prostate cancer. It uses precisely focused sound waves to target and destroy cancerous tissue within the prostate gland. The procedure aims to eliminate cancer cells without surgical incisions, offering a less invasive alternative for some patients.
What is High-Intensity Focused Ultrasound (HIFU)?
HIFU technology concentrates high-frequency sound waves at a specific focal point. When these sound waves converge, the energy converts into intense heat, raising the temperature within the targeted tissue to destroy cells through coagulative necrosis. This process is similar to using a magnifying glass to focus sunlight and generate heat at a single spot.
The precision of HIFU is an advantage, as it allows for the destruction of targeted cells while minimizing damage to surrounding healthy tissue. Beyond prostate cancer, HIFU has broader medical applications, including treating uterine fibroids and palliative ablation of bone metastases. This versatility shows its use as a precise, non-invasive tool for various medical conditions.
HIFU as a Prostate Cancer Treatment
For prostate cancer treatment, HIFU involves inserting an ultrasound probe into the rectum. This transrectal probe generates high-intensity ultrasound waves and provides real-time imaging of the prostate gland. Imaging techniques, such as magnetic resonance imaging (MRI) or ultrasound, guide the treatment, allowing the surgeon to precisely map the tumor’s location.
The focused sound waves are directed through the rectal wall to the prostate, heating and ablating (destroying) the cancerous tissue. Each energy pulse creates a small, ellipsoid-shaped area of destruction, about the size of a grain of rice. The HIFU machine systematically moves the beam to treat the entire target volume, eliminating cancerous cells while sparing adjacent structures like the urethra and nerves.
Patient Suitability for HIFU
HIFU is not suitable for all prostate cancer cases. It is considered for patients with localized prostate cancer, meaning the cancer is confined within the prostate gland and has not spread. Ideal candidates have low-to-intermediate risk disease, with a Gleason score of 7 or less. The tumor’s size and location are also important; for instance, lesions in the posterior or lateral prostate are more amenable to HIFU.
Prostate size can also influence suitability, as HIFU energy from the rectal probe has a limited reach. Large prostates or tumors located too far anteriorly may not be effectively treated. The presence of calcifications within the prostate can hinder ultrasound energy penetration and reflect heat back towards the rectum, making HIFU less effective or risky. Contraindications also include inflammatory bowel disease of the rectum, prior rectal surgery, or active infection.
What to Expect: Recovery and Results
Following a HIFU procedure, which is typically performed as an outpatient treatment, patients can return home the same day. A urinary catheter is often placed during the procedure and may remain for 5 to 7 days to manage post-treatment swelling of the prostate. Temporary urinary symptoms, such as urgency, frequency, a slower stream, or discomfort during urination, are common but generally improve within a few weeks. Some men may experience temporary erectile dysfunction, though this often resolves over time, with medication assisting recovery.
The success of HIFU treatment is monitored through regular follow-up assessments, including PSA blood tests and MRI scans. A decrease in PSA levels after treatment is an expected outcome, and a continuous rise can indicate recurrence. In some cases, a repeat biopsy may be performed several months after the procedure to check for any remaining cancer cells. Long-term outcomes for localized prostate cancer treated with HIFU are favorable, with studies showing high cancer-specific survival rates at 7 to 10 years, particularly for low and intermediate-risk patients.