The role of various forms of minimally invasive therapies has been greatly expanded to the previous standard of open radical nephrectomy. Although partial nephrectomy remains the reference standard, ablative techniques are increasingly applied in the management of small renal tumors with the long-term results emerging [
6]. Among ablative modalities, cryotherapy is the most widely used and accepted, especially for older patients in high risk [
7], and has shown to correlate with minimal complications and good intermediate-term oncologic outcomes [
8]. The application of cryoablation is to ablate solid tumors found in the lung, liver, breast, kidney, and prostate. Prostate and renal cryoablation are the most common. Although sometimes cryoablation is applied through laparoscopic or open surgical approaches, most often cryoablation is performed percutaneously. The advantages of percutaneous renal cryoablation include a less-invasive procedure, shorter hospitalization, excellent ice ball monitoring with ultrasound, less requirement for pain medication, and lower risk of metastatic progression [
9‐
11]. Most of all, it can be performed repeatedly [
12]. Compared to other thermal ablation, cryoablation offers real-time, visual feedback of the ice ball and it is nearly painless during the procedure, eliminating the need of general anesthesia or deep sedation. Percutaneous renal cryoablation can be performed by ultrasound, CT, or MRI guidance. Ultrasound is convenient and sufficient for precise needle placement, and what is more, it allows real-time guidance. The selected patients in this study are all not candidates for surgical procedure because they are not could not tolerate the postoperative pain and complications which general anesthesia brings.
As a matter of fact, the most common sequelae are self-limited pain and paresthesia at the sites of probe insertion related to cryoablation. Other complications that are rare include hemorrhage, infection, visceral injury, pneumothorax, and delayed UPJ obstruction. Mild perinephric hematoma, myoglobinaemia, and transfusion have been reported [
13‐
15], but in most cases, those complications could be managed rightly without operative procedure. By placing the cryoprobe perpendicularly into the kidney, carefully maintaining its position throughout the procedure, and deliberately removing the probe after complete thawing of renal tissue surrounding the cryoprobe, renal fracture and hemorrhage can be avoided [
7]. Uzzo and Novick published a cumulative total of 155 (13.7 %) complications in 1129 procedures in a review of nephron-sparing surgical procedures during the past decade [
16]. These complications include 14 deaths, 78 urinary fistulas, 3 splenic injuries, 19 infections or abscesses, 27 hemorrhages, and 18 patients had to receive postoperative dialysis [
16]. The results of cryoablation in our study are superior to this standard, especially when one considers that many high-risk patients would not be candidates for surgical procedure. Atwell reported the durability of this treatment method with a low incidence of tumor recurrence beyond 3 months in a midterm follow-up of 93 tumors of percutaneous renal cryoablation [
17]. Our recurrence rate of stage 1 RCC after successful cryoablation during a 2-year follow-up was 5.5 % (1/18). However, the repeated treatment was performed later resulting in the elimination of tumor enhancement. Although the local ablated tumor control was 100 % of patients including the recurrence case that received additional cryoablation at 2-year follow-up, we still need further investigation of the long-term safety and efficacy in tumor control. Moreover, in order to strengthen the treatment, cryoablation can be combined with preoperative or postoperative radiation therapy and chemotherapy treatment, which can be in our follow-up study.