A minimally invasive procedure for patients with benign primary bone tumors such as osteoid osteomas or oncology patients with systemic disease who do not have a surgical indication and do not have satisfactory control of metastatic bone disease by conventional therapies such as chemotherapy and immunotherapy, not even local control. of pain with radiotherapy and opioid analgesia, is thermoablation guided by interventional radiology methods, a thermal therapy that inactivates tumors with two different approaches: radioablation (with heat transfer) and cryoablation (with cold ). The treatment is the culmination of the 12th Annual Musculoskeletal Radiology Study Group (GERME) Thematic Course, an event taking place on Friday (18) and Saturday (19) at the Pullman Hotel, in Sao Paulo (SP). The realization is from the Paulista Society of Radiology and Diagnostic Imaging (SPR). Programming available on: www.spr.org.br/evento/120/curso-tematico-anual-do-germe/programacao.
Percutaneous ablation is a minimally invasive technique often performed in patients with benign or oligometastatic bone tumors to replace conventional surgery with a similar success rate; or in people with more advanced oncological disease who refuse traditional palliative care or in whom the outcome was suboptimal (not of the highest quality). It can even be performed on an outpatient basis andday clinic“, with sedation or general anesthesia, guided by ultrasound and computed tomography, using minimally invasive percutaneous techniques by the interventional radiologist. The technique can also be performed in open surgery, under intraoperative ultrasound guidance. In some cases, the patient can be discharged the same day or 24 to 48 hours after the procedure. Despite effective results, the technique is not widely available by the SUS and the ROL of the National Agency for Complementary Health (ANS) does not cover all indications.
“In Brazil, the biggest limitation is the cost. Inclusion in the ANS role is coverage of cases of hepatocarcinoma, a subtype of liver cancer and the osteoma osteoid/osteoblastoma, which is a benign primary bone tumour, inflammatory and painful, more common in pediatrics up to the age of about 20 years. All other indications, the patient can perform only by assuming the costs of the procedure. Even if the patient is eligible, which is the best cost-benefit ratio for a given situation and moment of the disease, seeking to obtain gains in the patient’s quality of life and a reduction in the number of readmissions and the dose of analgesia, we cannot do much precisely because of the cost limitation”, laments Marco Túlio Gonzalez, radiologist of the Osteomuscular Intervention Service of the Advanced Center for Diagnosis by Musculoskeletal Imaging of Grupo Fleury, who, in two course at GERME 2022, will talk about radioablation and cryoablation of tumors and metastases.
Evolution of the technique and indications – Ablation has been used for about two decades, however, Gonzalez contextualizes, the probe (needle) used was limited, allowing little control of the boundaries of the ablated (burnt) area relative to surrounding tissue, which has raised concerns in reason of the noble structures of the vicinity, like the vessels, the nerves and the hollow viscera. With the emergence of new technologies and new materials, both cryoablation and radiation ablation, the control of limits is of greater precision, safety and efficiency. “We manage to have millimeters of control between the lesion ablated by cold or heat and the adjacent tissues that must be protected or avoided”, underlines the interventional radiologist.
The specialist points out that ablation emerged to provide an opportunity for more effective control of pain, dysfunction and local control of the lesion for cancer patients. For patients with metastatic disease (for example, with a primary liver, bowel, lung, breast, prostate, or kidney tumor that has spread to bone), the first line of treatment is chemotherapy, immunotherapy and radiation therapy. , however, many of these metastatic tumors are resistant to these therapies. “The skeleton is the third most common site of metastases and without effective local control of these tumors there is a very negative impact on the quality of life of patients, due to poor pain control and increased bone fragility, especially in load-bearing areas, such as the bones of the pelvis and spine, facilitating the occurrence of pathological fractures, which leads to great morbidity, loss of autonomy and even more affecting the quality of the patient’s life”, reinforces Gonzalez.
Ablation is a method increasingly studied. Evidence indicates that it is also potentially curative in the treatment of oligometastatic patients, ie those with less than five secondary lesions and less than 2 centimeters. For them, ablations are an option to more invasive surgical methods, especially in lesions safely accessible by a percutaneous needle/probe. It stands out as the best option in radiation-resistant tumors or in those that respond to radiation, but where the patient has reached the cumulative dose limit or nearby tissues have a lower cumulative dose and local progression of the disease persists.
More good news, Gonzalez adds, is that while they’re still high, ablation costs are coming down because there are more responsible companies offering needles and other supplies. Studies indicate that the mid- and long-term cost of ablation methods is lower than that of recurrent hospitalizations for treatment of complications and palliation of pain with high doses of opioids. “The cost, in the end, ends up being lower for the healthcare system as a whole. Health officials need to have that perspective,” adds Gonzalez.
LEARN MORE ABOUT RADIOABLATION AND CRYOABLATION
Radioablation: the best known and widespread method in Brazil is radio frequency, where the electrode is coupled to a generator that emits radio frequency pulses, producing heat. By reaching 56 degrees, there is already irreversible cell damage, but generally the limit up to 90 degrees and more is worked, precisely to ensure that the entire volume of heated tissue dies, without the risk of carbonization of certain areas. and others with little exposure. . Radiofrequency ablation is more indicated for small lytic bone tumors (those that destroy bone, both primary and metastatic) and without significant extraosseous extension.
Cryoablation: the probe is cooled by a refrigerant gas (argon) and positioned inside the lesion, reaching temperatures that can reach -150°C and promoting the inactivation and death of tumor cells by exposure to a temperature of -40° vs. Cryoablation is indicated for larger tumors, which have already exceeded the bone boundary, already spreading to the surrounding soft tissues. It is the choice of bone-producing tumors, called sclerotic or blastic.
Oncology module – In addition to lectures by radiologist Marco Túlio Gonzalez, the oncology module of GERME 2022 will also have a lecture (previously recorded) by French radiologist Valérie Bousson, head of the osteoarticular radiology department at Lariboisière Hospital, who will talk about how to remove an osteoid osteoma. Also taking part in this module are radiologists A. Caudal and Luiz Tenório de Brito Siqueira who will discuss cervical vertebroplasties and thoracic and lumbar vertebroplasties respectively.
About SIYB 2022 – The 12th edition of the Annual Thematic Course of the Study Group of Musculoskeletal Radiology (GERME), of the Society of Radiology and Diagnostic Imaging of São Paulo (SPR) will take place on March 18 and 19, at the Pullman Hotel, in Sao Paulo. The program has eight modules: Introduction, Low Complexity Procedures, Upper Extremity, Miscellaneous, Spine, Oncology, Biopsies, and Case Discussion. Know more: www.spr.org.br/evento/238/curso-tematico-anual-do-germe/sobre-o-evento.