Published online Sep 6, 2019. doi: 10.12998/wjcc.v7.i17.2487
Peer-review started: March 28, 2019
First decision: April 18, 2019
Revised: August 1, 2019
Accepted: August 20, 2019
Article in press: August 20, 2019
Published online: September 6, 2019
To date, there are no guidelines on the treatment of solid neoplasms in the transplanted kidney. Historically, allograft nephrectomy has been considered the only reasonable option. More recently, nephron-sparing surgery (NSS) and ablative therapy (AT) have been proposed as alternative procedures in selected cases.
To review outcomes of AT for the treatment of renal allograft tumours.
We conducted a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 Checklist. PubMed was searched in March 2019 without time restrictions for all papers reporting on radiofrequency ablation (RFA), cryoablation (CA), microwave ablation (MWA), high-intensity focused ultrasound (HIFU), and irreversible electroporation (IRE) of solid tumours of the kidney allograft. Only original manuscripts describing actual cases and edited in English were considered. All relevant articles were accessed in full text. Additional searches included all pertinent references. Selected studies were also assessed for methodological quality using a tool based on a modification of the Newcastle Ottawa scale. Data on recipient characteristics, transplant characteristics, disease characteristics, treatment protocols, and treatment outcomes were extracted and analysed. Given the nature and the quality of the studies available (mostly retrospective case reports and small retrospective uncontrolled case series), a descriptive summary was provided.
Twenty-eight relevant studies were selected describing a total of 100 AT procedures in 92 patients. Recipient age at diagnosis ranged from 21 to 71 years whereas time from transplant to diagnosis ranged from 0.1 to 312 mo. Most of the neoplasms were asymptomatic and diagnosed incidentally during imaging carried out for screening purposes or for other clinical reasons. Preferred diagnostic modality was Doppler-ultrasound scan followed by computed tomography scan, and magnetic resonance imaging. Main tumour types were: papillary renal cell carcinoma (RCC) and clear cell RCC. Maximal tumour diameter ranged from 5 to 55 mm. The vast majority of neoplasms were T1a N0 M0 with only 2 lesions staged T1b N0 M0. Neoplasms were managed by RFA (n = 78), CA (n = 15), MWA (n = 3), HIFU (n = 3), and IRE (n = 1). Overall, 3 episodes of primary treatment failure were reported. A single case of recurrence was identified. Follow-up ranged from 1 to 81 mo. No cancer-related deaths were observed. Complication rate was extremely low (mostly < 10%). Graft function remained stable in the majority of recipients. Due to the limited sample size, no clear benefit of a single procedure over the other ones could be demonstrated.
AT for renal allograft neoplasms represents a promising alternative to radical nephrectomy and NSS in carefully selected patients. Properly designed clinical trials are needed to validate this therapeutic approach.
Core tip: Ablative therapy (AT) is a minimally invasive alternative to radical or partial nephrectomy for the treatment of renal allograft tumours. To date, limited data exist regarding long-term efficacy and safety. We performed a systematic review on radiofrequency ablation, cryoablation, microwave ablation, high-intensity focused ultrasound, and irreversible electroporation of neoplasms arising in the transplanted kidney and described treatment-specific and overall outcomes. In the considered cases, AT was successfully offered to all transplant recipients with benign tumours or with American Joint Committee on Cancer T1a N0 M0 renal cell carcinomas of the kidney allograft who were not suitable for more aggressive and demanding surgical treatments.