Lately, many advancements have been made in the field of oncology. You may have heard of some of them like- chemotherapy, radiation therapy and surgery. However, did you know that even sound waves can be used to treat cancer?
High-Intensity Frequency Ultrasound (in short, HIFU) was developed back in the 1940s but became popular very recently. It is a procedure that is minimally invasive (doesn’t require any surgical incision). HIFU uses ultrasound waves to treat conditions like tumors. Before we delve into the technical aspects of HIFU, let us look at how ultrasound works.
Ultrasound scans are used for imaging purposes. Ultrasound uses high-frequency sound waves to create real-time pictures or videos of internal organs. The sound waves are reflected back to the transducer (the machine that emits ultrasound waves). The machine records the wave that echoes back. Since the speed, direction, and distance waves travel differ, depending on the boundary they run into, a computer can interpret this information as a two-dimensional image on a screen.
However, in HIFU, ultrasound isn’t used to create images. These high-frequency waves interact with targeted cells in our body and heat them up to modify or destroy them. It’s similar to how a magnifying glass focuses sunlight on paper. In HIFU, many beams of the ultrasound focus on the exact tissue area that requires treatment. The highly focused energy from the ultrasound causes the temperature of the tissue to rise, and the heat destroys the targeted tissue area. The waves can pass through layers of tissue until they reach their target. This also protects the healthy parts of the tissue while ablating only the diseased parts of it. Providers often use magnetic resonance imaging (MRI) or ultrasound imaging to guide and assess the procedure.
A common type of HIFU is magnetic resonance-guided focused ultrasound or MRgFUS.
Most of the research for HIFU so far has been for treating prostate cancer. But it can also be used for:
Breast cancer
Cervical cancer
Womb cancer
Pancreatic cancer
Soft tissue sarcoma
and more.
HIFU for prostate cancer:
The first HIFU trials were completed in the 1990s which certified it as safe for ablating prostate cancer. Initially, HIFU was used to perform whole-gland ablations. While this application was successful, there was increasing interest in limiting treatment-related side effects by restricting the amount of the prostate that was treated. This treatment approach is termed focal therapy.
The ideal candidate for focal therapy typically has intermediate-risk prostate cancer located in only one area of the prostate. This location is determined by prostate magnetic resonance imaging (MRI) and targeted prostate biopsy.
The HIFU procedure is done while the patient is under the effect of anaesthesia. Once the patient is completely anaesthetized, an ultrasound probe is placed in the rectum. There are no incisions or even any needles used i.e. it is a non-invasive procedure. This ultrasound probe is used to both image the prostate and deliver the treatment. Once the initial positioning and planning steps are complete, treatment is delivered.
Each HIFU treatment lasts just a few seconds and destroys an area of tissue that is about the size of a grain of rice. An ablation zone is created by delivering multiple treatments to cover a predefined area of the prostate based on imaging and biopsy results. The procedure length depends on the size of the area to be ablated but in general, takes approximately two hours.
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Advantages of HIFU over other clinical procedures:
It is non-invasive and doesn’t require any surgical incisions into your body
It doesn’t require radiation therapy
It only targets diseased tissue, leaving the healthy parts of the organ unharmed
It is usually an outpatient procedure with minimal recovery time
It has fewer, and less complicated side effects than radiotherapy, surgery or chemotherapy
Although HIFU is not as prevalent as chemotherapy or radiation therapy, it shows promising, favorable results. There are a lot of factors to take into consideration before opting for HIFU treatment but till now, it has been the safest alternative to chemotherapy and other high-risk procedures.
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