Prospective long-term experience in the treatment of renal tumors with cryotherapy: follow-up with computed tomography scan and contrast-enhanced ultrasound.

Introduction: The aim of this article was to evaluate the oncological results and safety of cryotherapy for the treatment of renal tumors.

Material and methods: This study was a prospective review and follow-up of patients who underwent cryotherapy from January 2008 to May 2021. Cryotherapy was offered to patients with bilateral tumors, tumors in solitary kidneys, or comorbid patients. Follow-up consisted of a computed tomography (CT) scan and contrast-enhanced ultrasound (CEUS), with analysis of concordance (kappa index). Overall survival and kidney survival were analyzed (Kaplan-Meier).

Results: Cryotherapy was performed 71 times in 67 patients. A total of 74.6% of patients were men. The mean age of patients was 69.7 years (standard deviation (SD) 11.3]. Mean follow-up was 52.7 months (SD 36.2). Mean tumor size was 26.2 mm (SD 7.6). 90% were cT1a, 10% cT1b stage. Type of access was open in 1 patient, laparoscopic in 8, percutaneous US-guided in 8 and percutaneous CT-guided in 54 patients. Biopsy was taken in 60 patients (84.5%) and consisted of renal cell carcinoma (22), oncocytoma (9), papillary carcinoma (4), angiomyolipoma (1), sarcoma (1), and non-conclusive (23).There were 22 complications such as pain in 2 patients, hematoma in 8 and 2 cases of bleeding, all resolved conservatively except for one case of bleeding which required embolization.Recurrences occurred in 16 cases (22.5%). Management was cryotherapy in 25%, radical nephrectomy in 31.3% and surveillance in 43.8%. Concordance between contrast-enhanced ultrasound and CT was 0.8 (excellent).Mean glomerular filtration did not change. One patient developed metastasis.No cancer-specific mortality was found. Overall survival at 12, 24 and 48 months was 98.5%, 96.8% and 76.9% respectively. Kidney survival at 12, 24 and 48 months was 97%, 93.5% and 93.5% respectively.

Conclusions: Cryotherapy for renal tumors is a safe treatment for comorbid or solitary kidney patients, with rare major complications and good oncological outcome.