Yeaman C, O’Connor L, Lobo J et al: Perioperative cost comparison between percutaneous microwave ablation and partial nephrectomy for localized renal masses. Urol Pract 2021; 8: 630.

As health care costs in the United States continue to rise, it is important to evaluate the costs of treatment options and weigh these costs against anticipated clinical benefit. Because there is a system-wide lack of transparency about costs and cost allocation, determining true health care costs is difficult. Further, there is disagreement upon what degree of clinical benefit is worth compared to the added costs of a rival procedure. This discord prompted our cost comparison for the management of localized renal masses (LRM). At the University of Virginia, in addition to active surveillance, we commonly perform percutaneous microwave ablation (MWA) and partial nephrectomy (primarily robotic-assisted when feasible) for LRM. Other institutions may use cryoablation or radiofrequency ablation (RFA). We ceased performing cryoablation in 2015 due to simpler logistics, faster procedure time, better oncologic results, and fewer complications that we observed with MWA. We aimed to determine how the costs of partial nephrectomy and MWA compare, accounting for patient characteristics, complications and local recurrence risk.

Partial nephrectomy is commonly preferred for the management of localized renal masses due to lower risk of local recurrence. AUA guidelines include ablative therapies for masses <3 cm in size.¹ Recent studies have demonstrated that ablative therapies have similar recurrence risk to partial nephrectomy.² It is important to recognize that all ablative therapies are not equal, and each modality should be evaluated fully on its own merits. While MWA is utilized by relatively few centers at present, it is important that urologists are familiar with MWA and its efficacy respective to RFA and cryoablation.

We queried institutional cost data from patients who were treated with either robotic-assisted partial nephrectomy (RA-PN) or percutaneous MWA from 2015–2020. A total of 279 patients were identified. Of these patients 165 underwent percutaneous MWA, and 114 underwent partial nephrectomy. Total cost is comprised of medical center cost and physician related cost. Medical center cost consists of direct cost (supplies, medications, labs and nonphysician labor) and indirect cost (overhead related to facilities, equipment and maintenance). The mean total cost was $20,536 for RA-PN and $6,470 for percutaneous MWA (p <0.0001). Five patients (3%) who underwent MWA experienced Clavien-Dindo 3 complications or higher, compared to 7 patients (6%) who underwent RA-PN. Patients who underwent MWA and did not have a major complication had an average medical center cost of $5,174 compared to $8,990 for those with a major complication (p=0.36). Among patients who underwent RA-PN, those who did not have a major complication had an average medical center cost of $15,138 compared to $28,940 for those who did have a major complication (p=0.008). MWA incurs lower perioperative cost than RA-PN and the complications of MWA are less costly on average.³

With respect to health care costs, it is prudent to consider the clinically acceptable tradeoff between risk of local recurrence and increased cost. This is especially important in the consideration that partial nephrectomy carries a higher risk of serious complications than ablation and those complications result in higher costs. Traditionally, ablative therapies have been criticized for high rates of local recurrence. Our institutional data and other contemporary series are demonstrating recurrence rates around 2.5%.⁴ Is a 2% higher risk of local recurrence an acceptable tradeoff for a threefold reduction in treatment cost? Consideration of the costs incurred by patients in the treatment of small renal masses is a patient centered goal that should be considered within a shared decision making conversation between urologists and patients. Traditionally, cost-effectiveness analyses are employed modeling quality adjusted life-years gained by a given procedure compared with the cost incurred.⁵ Cost-effectiveness analysis of this kind has not been performed comparing MWA and RA-PN to date. This study provides cost information regarding MWA which has not been widely reported before as well as updated cost data for partial nephrectomy.

There are logistical and sometimes political factors which limit the utilization of MWA for patients with LRM. Partial nephrectomy is performed by urologists, while ablative procedures are typically performed by interventional radiologists. Referral patterns for small incidentally discovered renal masses may impact treatment options patients are offered. Our institution has employed a collaborative approach to the management of small renal masses. We have had a LRM conference since 2015 that allows for multidisciplinary (urology, radiology, pathology) decision making to consider the tradeoffs of each treatment for individual patients. We attribute our institutional successful experience with MWA in large part to the interdisciplinary planning we employ.

The costs of procedural options for small renal masses merit periodic evaluation given that medical costs are increasing at a rate which outpaces inflation.⁶ The data presented in our study may prove beneficial for further cost-effectiveness analyses regarding localized renal mass treatment.