Microwave ablation of renal tumors: state of the art and development trends

Abstract

In the last decades an increased incidence of new renal tumor cases has been for clinically localized, small tumors \2.0 cm. This trend for small, low-stage tumors is the reflection of earlier diagnosis primarily as a result of the widespread and increasing use of non-invasive abdominal imaging modalities such as ultrasound, computerized tomography, and magnetic resonance imaging. Renal tumors are often diagnosed in elderly patients, with medical comorbidities whom the risk of surgical complications may pose a greater risk of death than that due to the tumor itself. In these patients, unsuitable for surgical approach, thermal ablation represents a valid alternative to traditional surgery. Thermal ablation is a less invasive, less morbid treatment option thanks to reduced blood loss, lower incidence of complications during the procedure and a less long convalescence. At present, the most widely used thermal ablative techniques are cryoablation, radiofrequency ablation and microwave ablation (MWA). MWA offers many benefits of other ablation techniques and offers several other advantages: higher intratumoral temperatures, larger tumor ablation volumes, faster ablation times, the ability to use multiple applicators simultaneously, optimal heating of cystic masses and tumors close to the vessels and less procedural pain. This review aims to provide the reader with an overview about the state of the art of microwave ablation for renal tumors and to cast a glance on the new development trends of this technique.

Novel magnetic heating probe for multimodal cancer treatment

“…Modern probe based treatment modalities, such as ours, are becoming increasingly important for cancer treatment because they are less invasive treatment options due to reduced blood loss, lower incidence of complications during the procedure and relatively shorter convalescence compared with surgery. 48 Radiofrequency ablation (RFA) probes remain the most widely used ablative technique worldwide; 49 however, issues related to heat sink effect and charring lead to decreased ablation zones. 49 Furthermore, RFA is a contact thermal technique that requires good contact between the RF probe tip in the biological media to generate heat.…”

Trends in Percutaneous Thermal Ablation Therapies in the Treatment of T1a Renal Cell Carcinomas Rather than Partial Nephrectomy/Radical Nephrectomy

“…14,[32][33][34][35] Major complications of MWA are approximately 4% and include bleeding, infection, urine leak, stricture, and nontarget ablation including skin burn if the target is within 3 cm of the skin. 20,[34][35][36][37][38][39] Other technologies including IRE, high-intensity focused US, radiosurgery, pulsed cavitational US, and laser thermal therapy remain investigational at this time. 21,29 For both RFA and MWA, ablated lesions are hyperechoic on US and hyperdense on CT with low T2 and high T1 signal on MRI without enhancement of the lesion and a surrounding margin on all modalities.…”

Microwave ablation compared to thyroidectomy to treat benign thyroid nodules

“…Particularly, LA and RFA may provide a less expensive and less invasive alternative to thyroid surgery without the risk of subsequent skin scarring or hypothyroidism [17]. Microwave ablation (MWA) is an important minimally invasive technique used for benign and malignant tumors of the liver, lung, kidney and thyroid [18][19][20][21][22][23] that has expanded the range of nonsurgical minimally invasive treatment options. However, there have been no studies to date comparing the clinical efficacy of surgery and MWA.…”