Radio frequency ablation (RFA) enables doctors to destroy abnormal growths, quell arrhythmias and halt nerves’ transmission of pain signals.
Needlelike RFA probes generate heat that chars tissues within a millimeter or two of the probe’s tip. This is fine for small targets but the technology has been limited by its short range – the charred tissue impedes more distant ablation – and by somewhat unpredictable heat patterns caused by single-polarity probes (two or more probes have been needed to conduct energy).
Recent advances have overcome these challenges, thereby increasing RFA’s utility against cancer.
“The range increases to a sphere about the size of a ping-pong ball. If you need to ablate a malignant tumor, this type of device is effective,” said Michael Gofeld, a specialist at the UWMedicine Center for Pain Relief at UW Medical Center-Roosevelt.
New probes are internally water-cooled, which dissipates the heat around the needle such that tissue is ablated but without residual char. This extends the instrument’s reach. Also, the placement of positive and negative conductors on one probe creates a predictable zone of ablation.
Cancer specialists typically refer patients to Gofeld to relieve pain after chemotherapy and multiple external-beam radiation therapies have failed against the metastases. A metastases is cancer that has moved to another part of the body from its original location. Gofeld frequently treats people whose lung, kidney or breast cancer has spread, excruciatingly, to the pelvis or spine. Metastatic prostate cancer is most prone to invade bone but its accompanying pain is more diffuse, he added.
“Patients with a bone metastasis receive radiation therapy as the standard of care,” he said, “but a large portion of them are not candidates because of vital organs located nearby or because they have exceeded the maximum radiation dose. About 30 percent of patients don’t respond to radiation at all. Others cannot lie still for the treatment because of pain.”
For these patients, some cancer specialists may perceive hospice care and high-dose opioid painkillers as the lone remaining options. Gofeld instead would propose RFA – and as an earlier consideration, too.