This lecture aims to provide an overview of minimally invasive treatment options in metastatic renal cell carcinoma (RCC) and insights into this rapidly evolving treatment – from transcatheter to image guided thermal ablative therapy. RCC is the most common type of kidney cancer and the detection of RCC has increased over the past decade. The increased detection rate is due to a wider usage of radiology (e.g. ultrasound, CT or MRI) and this usually results in the detection of smaller RCC with earlier stage disease or even earlier detection of tumour spread.
What does interventional radiology offer in the treatment of metastatic RCC disease?
The most frequent sites of RCC metastatic disease and recurrence are the lung, bones, soft tissue, and brain. Marked advances in the treatment of mRCC have been made with novel VEGFR tyrosine kinase inhibitors and multiple immune checkpoint inhibitors that have been included in the current treatment paradigm of mRCC. Furthermore, remarkable advances have been made with the combination of double checkpoint blockade. The combination of ipilimumab and nivolumab compared with sunitinib has shown to increase the overall survival in the intermediate- and poor-risk patients based on the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model.
Despite these tremendous advances in systemic treatment options, still few patients experience a long-term durable response. Depending on the location of the metastatic disease, patients may suffer from treatment refractory pain or an elevated risk of fractures. Data from various studies illustrated that the combination of these new systemic agents with local treatment of metastases or recurrences were prognostic factors of longer overall survival.
Preoperative embolization, prior to (impending) fracture stabilization is used to reduce perioperative blood loss. Preoperative embolization of metastases was originally described for hypervascular tumours such as renal cell carcinoma and thyroid carcinoma. However, there is no consensus in the guidelines or literature as to which types of long bone metastasis benefit from preoperative embolization in order to reduce blood loss. Embolization may reduce perioperative blood loss or blood transfusion requirement and may ease the surgical procedure.
Thermal ablation (RFA, MWA, cryoablation)
Since 2000, thermal ablation has become more widely available in clinical practice. Recently, radiofrequency ablation (RFA), cryoablation, and microwave ablation (MWA) have become the main thermal ablation modalities. Despite the lack of strong evidence, the American and European Urologic Associations recommend thermal ablation as a primary treatment option for patients with RCC who cannot undergo surgery because of the high risk of postoperative morbidity. These conditions include poor cardiopulmonary function, chronic kidney disease, bleeding tendency, coagulopathy, and other severe comorbidities. Furthermore, thermal ablation can be a good alternative treatment option for hereditary, single kidney, central, and recurrent RCCs following surgery or thermal ablation and metastatic disease in selected patients.
Skeletal metastases are very destructive in patients with renal cell carcinoma, compromising bone integrity and leading to skeletal related events such as pain, impending fractures, nerve compressions, hypercalcemia and even pathological fractures which may require surgical interventions and other therapy. In addition to skeletal complications, the presence of bone metastases in RCC has a negative impact on progression free survival and overall survival of patients treated with systemic therapies. Cementoplasty includes percutaneous procedures like vertebroplasty, kyphoplasty, osteoplasty, and sacroplasty. Bone packing with cement aims to treat or prevent vertebral and extraspinal pathological fractures and relieve pain in patients with bone metastases from renal cell cancer. Percutaneous cementoplasty is a key element of modern pain management therapy for the treatment of painful bone metastases. Treating physicians should evaluate each patient carefully and have a thorough knowledge of the anatomy and the various techniques for image-guided lesion access and cement injection. Understanding the particular advantages and limitations of the various modern filler materials is also crucial for a successful and complication-free procedure.