SUO 2017: Ablative Technologies for Kidney Masses
The recently published 2017 AUA guidelines [3] make several recommendations regarding thermal ablation. Physicians should consider thermal ablation as an alternate approach for the management of cT1a renal masses <3 cm in size. Furthermore, for patients who elect thermal ablation, a percutaneous approach is preferred over a surgical approach whenever feasible to minimize morbidity. Counseling about thermal ablation should include information regarding an increased likelihood of tumor persistence or local recurrence after primary ablation relative to surgical treatment, which may be addressed with repeat ablation. Furthermore, renal mass biopsy prior to or concurrent with thermal ablation is strongly advised.
Contemporary laparoscopic cryoablation outcomes suggest a recurrence-free survival (RFS) of 87-95% at 10 years of follow-up, whereas RFS for percutaneous cryoablation is 93-98% at 17-32 months. Radiofrequency ablation (RFA) according to Dr. Atwell is great for small tumors (≤3 cm) with RFS rates of 97-100%. Furthermore, RFA has RFS rates of 98-100% for exophytic tumors compared to 62-82% for endophytic tumors. The limits of RFA have recently been pushed with the advent of microwave ablation. This technique is more robust and faster compared to RFA and has local RFS rates of 89-99% at 15-26 months of follow-up. The potential for utilizing cryoablation for larger tumors has also recently been assessed, noting that tumor size and number of probes used are not significantly associated with tumor recurrence, with no differences noted between tumors larger or smaller than 3cm. However, risk factors for bleeding associated with cryoablation (4% risk) include (i) increasing tumor size, (ii) number of cyroprobes, and (iii) central location.
As mentioned in the ASCO guideline [2], collaboration is important noting that “a working relationship between an interventional radiologist and urologic kidney surgeon provides an optimal and safe approach.” Dr. Atwell concluded with several take-home points (i) ablation is a viable option for treatment small renal masses, specifically RFA for exophytic masses < 3cm and cryoablation for larger masses and potentially central masses, and (ii) urology directed, collaborative care is best for patients.
References:
1. Ljungberg B, Bensalah K, Canfield S, et al. EAU guidelines on renal cell carcinoma: 2014 update. Eur Urol 2015;67(5):913-924.
2. Finelli A, Ismaila N, Bro B, et al. Management of Small Renal Masses: American Society of Clinical Oncology Clinical Practice Guideline. J Clin Oncol 2017;35(6):668-680.
3. Campbell S, Uzzo RG, Allaf ME, et al. Renal Mass and Localized Renal Cancer: AUA Guideline. Available at: http://www.auanet.org/guidelines/renal-mass-and-localized-renal-cancer-new-(2017)
Presented by: Thomas D. Atwell, MD, Mayo Clinic, Rochester, MN
Written by: Zachary Klaassen, MD, Society of Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre @zklaassen_md at the 18th Annual Meeting of the Society of Urologic Oncology, November 20-December 1, 2017 – Washington, DC