Ablative Therapies for T1b Renal Tumors
I read with interest the recent article by Takaki et al1 regarding the comparable efficacy of radiofrequency ablation (RFA) and radical nephrectomy in treating patients with stage T1b renal cell carcinoma (RCC). The article highlights the advancing abilities of percutaneous minimally invasive techniques to parallel surgical outcomes, despite the fact that these therapies are generally offered in a more compromised cohort of individuals due to surgical comorbidities or impaired renal function.
From an interventionalists perspective, it is noteworthy that the distinction for T1b renal tumors is a size ≥4 cm. Large series have demonstrated that a maximal diameter size cutoff of 3 cm is a strong determinant of RFA success,2,3 supportive of initial studies.4 The application of RFA for tumors exceeding 4 cm represents a more recent extension of this therapy into a harder clinical subset. But is there a difference?
We have recently evaluated outcomes in 40 renal RFA procedures and compared the results between lesions ≤3 cm vs >3 cm. Ablation times were longer for the larger lesions, as were primary recurrence rates. However, after performing repeat ablation on three tumors initially larger than 3 cm, secondary recurrence rates were comparable on follow-up ranging from 3 months to 4 years. A regression analysis of the rates of reduction in tumor size after ablation also were similar for larger and smaller lesions.
Percutaneous therapies continue to evolve and potentially offer the promise of equal effectiveness and lowered procedural morbidity for patients with more complex lesion sets or clinical scenarios. Whether the experience of Takaki et al. will increase the use of RFA in the more “typical” RCC patient having good surgical risk remains to be seen.
References
1. Takaki H, Soga N, Kanda H, et al. Radiofrequency Ablation versus Radical Nephrectomy: Clinical Outcomes for Stage T1b Renal Cell Carcinoma. Radiology. 2014;270:292-299.
2. Wah T, Irving H, Gregory W, Cartledge J, Joyce A, Selby P. BJU Int. 2013 Jul 2. doi: 10.1111/bju.12349. [Epub ahead of print]
3. Atwell TD, Schmit GD, Boorjian SA, et al. Percutaneous Ablation of Renal Masses Measuring 3.0 cm and Smaller: Comparative Local Control and Complications After Radiofrequency Ablation and Cryoablation. Am J Roentgenol. 2013;200: 61.
4. Watanabe F, Kawasaki T, Hotaka Y et al: Radiofrequency ablation for the treatment of renal cell carcinoma: initial experience. Radiat Med. 2008;26:1-5.
