Cryotherapy

The evaluation and management of a renal mass is discussed in detail in the renal mass/nephrectomy newsletter. Surgery, which includes partial nephrectomy and total nephrectomy, has remained the main form of treatment for renal masses. In a select subset of patients other forms of treatment may be available which include cryotherapy and thermal ablation.

It is of note that with the increased use of abdominal imaging, about half of all renal masses are found incidentally when a study is done to investigate another clinical problem. These masses are often found at a smaller size and at an earlier stage. In years past when a renal mass was present, the only treatment option available was removal of the entire kidney (nephrectomy). In current practice, small renal masses can be safely removed with excision of just part of the kidney (partial nephrectomy). Recently, the American Urological Association has approved additional less invasive therapies for renal masses, which include thermal ablation and surveillance.

Thermal ablation and surveillance may be considered if a small renal mass is found in an elderly patient or a patient with multiple medical problems.

Thermal Ablation

There are two types of thermal ablation recommended today. Cryotherapy uses a gas to freeze the mass in the kidney. Radiofrequency ablation uses energy waves to heat and kill the mass. Both of these are administered by placing one or more thin probes into the mass.

This can be done under imaging guidance (ultrasound, computed tomography, MRI), via laparoscopic surgery or open surgery. Biopsy of the mass is typically taken prior to thermal treatment.

Thermal ablation is minimally invasive and has a short recovery period. However, these therapies do not have long term follow up information, as compared to surgical removal techniques, so the long term outcomes are unknown. Ongoing monitoring of the area of the mass, with some type of imaging such as computed tomography (CT scan) or ultrasound is necessary.

Complications

The major urological complication rate for cryoablation is hemorrhage (4.9%). Other complications include potential hazards associated with general anesthesia or patient positioning. Surveillance may require repeated imaging with contrast injection, which can decrease kidney function. Recurrence may require repeat treatment or surgery. If surgery is needed after a thermal ablation procedure, it may be more difficult due to reaction from the initial treatment.

Summary

Renal cryoablation may be a treatment option for patients at high surgical risk who want proactive treatment and accept the need for lifelong surveillance and the increased chance of recurrence compared to surgical removal.