A commentary on “Ablative therapies versus partial nephrectomy for small renal masses – A systematic review and meta-analysis” [Int. J. Surg. (2021) 97 106194

Abstract

Dear Editor, The incidence of renal cancer, especially presenting as small renal masses, has risen during the last decade. For primary treatment of small renal masses, guidelines recommend nephron-sparing surgical approaches, such as partial nephrectomy (PN). Thermal ablation techniques are an alternative treatment option, mainly being recommended for frail patients. To compare oncological outcomes in patients undergoing ablative therapies (AT) versus PN for small renal masses, Chan et al. [1] performed a systematic review and meta-analysis of 33 clinical trials and demonstrated that AT had similar long-term oncological results; lower rates of complications and superior kidney function preservation when compared to PN. AT is a reasonable alternative to PN in frail and co-morbid patients. Ablation techniques have developed fast in past several years. It can be guided by ultrasound or computed tomography, which gives more alternative choices of performing ablation under local or general anesthesia to meet different patients’ need. As ablation can be performed in different ways, it is more appropriate for patients compared with PN. Tissue destruction of small renal masses has been performed mainly using two techniques: cryoablation and radiofrequency (RF) ablation using a percutaneous approach for posterior lesions and a transperitoneal laparoscopic approach for anterior masses. Cryoablation causes tissue destruction by insertion of a hollow cryoprobe through which argon and helium gases are circulated. An expanding ice ball forms which causes cell death by destruction of cell membrane and internal structures, as well as by ischemia. When percutaneous and laparoscopic approaches are compared, the former approach has the advantages of reduced pain, shorter hospitalization and faster convalescence time, but a higher primary failure rate [2]. RF ablation comprises of insertion inside of a small renal mass a multi-pronged needle to which mono or bipolar RF is applied, thus generating local heat. When temperatures between 50° and 100 °C are maintained, coagulation necrosis is obtained, causing irreversible cell damage. During this treatment, large renal vessels have a heat sink effect, and peripherally located tumors are more easily treated. Tumor ablation is rational in treating patients with a small renal mass in a solitary kidney, or in patients with multiple recurrences due to genetic alterations, when preservation of renal function is more relevant than radical tumour removal [3]. Ablative therapies are not recommended for centrally located masses close to pyelocaliceal systems and ureters, for masses greater than 3 cm in diameter or masses with irregular and infiltrative borders [4]. Other contraindications are severe coagulation disorders, young age, or presence of metastatic lesions. Patients after tumour ablation have to accept the need for frequent cross-sectional imagings on follow-up. To reduce costs and radiation exposure, contrast-enhanced ultrasound has been proposed, which has high specificity and negative predictive values. The pathological characteristics of even a small renal mass can affect prognosis [5]. Future high-quality randomized controlled trials are required to confirm the potential benefits of ablative therapies. Ethical approval None. Sources of funding None. Author contribution Yefei Ding-writing. Yan Cheng-data collection. Guanli Huang-study design. Research registration Unique Identifying Number (UIN) None. Guarantor Yefei Ding. Provenance and peer review Commentary, internally reviewed. Declaration of competing interest None.