Ablations for pain relief
The primary objective of ablation in oncology is to completely kill the tumor. However, in some cases, pain relief may be more important than the treatment of the tumor. In such cases, ablation can be used not to kill the tumor completely, but to relieve or reduce the pain it creates (palliative ablation).
Ablation is one of the most important methods used to treat pain in oncology. Although radiotherapy is the most common method for this purpose, it has some disadvantages in the palliation of pain:
1. Pain reduction in radiotherapy occurs late (after 1-2 weeks).
2. Is not beneficial in about 1/3 of patients.
2. Even the pain is relieved, in about half of the patients it may recur after some time. However, radiotherapy cannot be applied to the same area.
In contrast, pain relief starts immediately after ablation and lasts longer. It is generally more effective than radiotherapy, and if the pain relapses ablation can be repeated as many times as necessary in the same region.
The most common methods of percutaneous ablation to relieve pain are radiofrequency, microwave and cryoablation. All of these methods are beneficial, but cryoablation is more effective and advantageous because the procedure can be performed under local anesthesia and can permanently destroy nerve cells without causing any pain. All three ablation methods are performed by inserting needles from the skin into the tumor or the area where the pain occurs.
Apart from these methods, the HIFU (High Intensity Focused Ultrasound) can also be used to relieve the pain, which can do ablation noninvasively (without sticking any needle). In the HIFU, high intensity sound waves are focused into the tumor from outside the body with a special lens. These waves form a temperature of around 80-100 degrees in the area of several millimeters. Ablation can be performed in large areas by moving this focus within the tumor. HIFU is mostly used to treat uterine fibroids from outside the body without surgery. Another area of use approved by the FDA (Food and Drug Administration) in America is pain relief of bone metastases. For this, HIFU is applied to the area where the tumor destroys the bone membrane (periosteum) and the nerves in this area can be killed to reduce the pain.