discussion
Approximately 40% of cancer patients develop metastatic disease; 50% of these patients have poorly controlled pain.
Various therapies, including chemotherapy, hormonal therapy, localized irradiation, systemic radioisotope therapy, biphosphonate therapy, and surgery, may be used in an attempt to provide palliative pain relief.
Some patients fail to derive satisfactory pain relief with these therapies, and relief, when achieved, may not occur until 4–12 weeks after the initiation of the treatment. When these methods are not possible or are not effective, analgesic medications remain as the only current alternative therapy.
The main advantage of radio-frequency ablation is the ability to create a well-controlled focal thermal injury with minimal morbidity and mortality.
Unlike alcoholization (ethanol ablation), radio-frequency ablation creates a well-demarcated lesion. The bipolar technique is able to create a strictly limited coagulation between the electrodes and the duration of the ablation is relatively short.
Radiofrequency is particularly indicated for tumor therapy. While alcoholization is preferred in palliative bone metastases pain management because of its simplicity and low cost. However, the risk of leakage, collateral damage, necessity of multiple needle insertions, and the uneven distribution of ethanol are major limits with this technique.
The size of the thermal injury created by a single radio-frequency ablation is larger than that created by a single laser ablation; hence, there is less chance of missing large tumor.
The management of patients with bone metastases requires consideration of many factors:
- careful evaluation of the patient's general condition,
- an understanding of the disease process,
- an appreciation of the degree of bone destruction (consolidation),
- and working knowledge of available treatment options is required.
A factor of concern with RF ablation is the time currently necessary for the RF ablation treatment, particularly for large lesions (multiple applications necessary). These treatments require an average of 2 hours of anesthesia time with the patient in the CT suite; a substantial component of the time necessary for the procedure was an average of 40 minutes of ablation time. Optimization of RF electrode energy deposition especially with bipolar technique may allow a decrease in the amount of time necessary for this procedure. In the evaluation of this technique the cost should also be taken into account.
CONCLUSION
Pain management in cancer patients is an important and difficult task. In patients for whom anticancer therapy provides no relief or who have recurrence of pain that is not amenable to further palliative measures, it is essential to treat the pain symptomatically. RF ablation provides a potential alternative method for palliation of painful osteolytic metastatic lesions; the procedure is safe, and the pain relief is substantial.
Curative ablation is performed in some specific cases like bone metastases of thyroid cancer. The treatment begins with radio frequency ablation destroying more than 90% of the lesion allowing a radioisotope therapy (131- iodine) to complete the ablation of residual tumor.
A multidisciplinary approach is essential to determine the course of treatment that best alleviates pain, preserves function, and optimizes the quality of life remaining in the patient with metastatic disease. An combination of different methods could be necessary to treat cancer pain efficaciously and thermal ablation is another modality which could be useful in this therapeutic battery.
