Prof Saim Yılmaz, MD
"HIFU is a viable treatment option in only 1/4 of patients with uterine fibroids"
In which patients with fibroids is HIFU treatment effective?
HIFU (High Intensity Focused Ultrasound) is the process of focusing high-intensity ultrasound waves on the desired tissue with the help of a lens under the guidance of MRI or ultrasound and burning that tissue with the high heat generated. HIFU is a method that has been increasingly used in cancer treatment in the last 10 years. HIFU tudies are mostly carried out on prostate, pancreas, bone and soft tissue tumors. However, it has not been clearly revealed yet to what extent the method is successful in which tumor types. Also, comparative studies with other proven treatment modalities are scarce. The method has also been used in uterine fibroids and promising results have been obtained. The most important advantage of HIFU is that it provides treatment without any incision in the skin and the hospital stay is short. However, the method also has some disadvantages and limitations.
For HIFU, ultrasound waves must be able to reach the tumor from the skin without any obstruction. However, bone tissue and organs filled with air (lung, stomach, intestine, etc.) block ultrasound waves. Therefore, if there are such tissues or organs between the skin and the target tumor tissue, HIFU cannot be applied. In addition, while the tumor is burned during the procedure, heating occurs also in the tissues next to the tumor. This may cause leg pain, skin burns or hardening of the subcutaneous fat tissue as well as sciatic nerve damage in some patients.
In the HIFU, the tumor is displayed on the ultrasound or MRI screen, and the focal point of the ultrasound waves is constantly shifted within the tumor, trying to burn every part of the tumor. This is a long and time-consuming process. Especially if it is done under the guidance of MRI, the cost increases as the MRI devices are very busy and have to be reserved for this process for a long time. The more the number and diameter of the tumors are, the longer and more costly the HIFU is. For this reason, HIFU may be a good option in patients with a single or several fibroids in the uterus that are not very large in diameter, especially if the fibroids are located close to the skin. Hayfu application is not practical in patients other than this group of patients. In addition, for HIFU, the fibroid must be seen on ultrasound or MRI. HIFU will not have any effect on small fibroids that cannot be seen with these methods. Studies have shown that HIFU can only be applied in about 25% of myoma patients, and that it is not a suitable option for the remaining patients.
HIFU is a method with few side effects and complications. However, there are some questions about its long-term effectiveness in fibroids. This is because it is difficult to burn all of the fibroids at once with HIFU. For this reason, the procedure may need to be repeated several times in order to completely burn the fibroid. Fibroids that are not completely treated can grow back and cause problems. In a study comparing HIFU with percutaneous radiofrequency ablation, it was found that the rate of complete burning of fibroids was lower with HIFU (Meng X et al, CVIR 2010). It has also been shown that secondary treatments are needed more more frequently (Froeling et al, CVIR 2013). Despite this, HIFU treatment is an important option in suitable patients. However, it is a costly method and devices used for uterine fibroids are not yet available in many countries.
Video: HIFU and other treatment options in myoma, Prof Dr Saim Yılmaz