Renal Insufficiency Is Not a Contraindication for Cryoablation of Small Renal Masses

Effects of percutaneous cryoablation for renal tumor on overall and split renal function

PURPOSE

To evaluate retrospectively the influence of percutaneous cryoablation for small renal tumors on total and affected kidney function and risk factors associated with worsening function of the affected kidney.

MATERIALS AND METHODS

Between April 2016 and March 2022, 27 patients who underwent cryoablation for small renal tumors at our institution participated in this study, which investigated time-dependent changes in postoperative renal function. We evaluated estimated glomerular filtration rates (eGFRs) and split renal function revealed by scintigraphy using 99 m technetium-mercaptoacetyltriglycine (99mTc-MAG3) before cryoablation and at 1 week, 1 month, and 6 months after cryoablation. Numerous variables were analyzed to assess risk factors for worsening renal function.

RESULTS

Baseline eGFR (mean ± standard deviation) was 56.5 ± 23.7 mL/min/1.73 m2 (mean ± SD; range, 20.5-112.5). Mean eGFRs at 1 week, 1 month, and 6 months after cryoablation were 57.4 ± 24.5 (19.1-114.9), 57.1 ± 25.1 (21.5-114.9), and 53.8 ± 23.9 mL/min/1.73 m2 (20.0-107.5), respectively. Changes were statistically insignificant (p = 1.0000, = 0.6749, and = 0.0761, respectively). Regarding split renal function, mean baseline contribution of the affected kidney determined by 99mTc-MAG3 was 49.7% ± 6.0% (38.8-63.3%); these rates at 1 week, 1 month, and 6 months after cryoablation were 43.7% ± 8.8 (29.1-70.6%), 46.2% ± 7.7% (32.6-70.3%), and 46.0% ± 8.5% (32.5-67.6%), respectively. Differences from baseline were significant for all periods (p < 0001, < 0001, = 0.0001, respectively). Serum C reactive protein and lactate dehydrogenase at 1 day following cryoablation, tumor's nearness to the collecting system or sinus, and volume of ablated normal renal parenchyma were significantly correlated with decreased contributions of the affected kidney by > 10% after cryoablation.

CONCLUSION

Unlike total renal function, affected kidney function could worsen after cryoablation.

Thermal ablative therapies for treatment of localised renal cell carcinoma: a systematic review of the literature

BACKGROUND AND AIMS

Small renal masses are commonly diagnosed incidentally. The majority are malignant and require intervention. The gold standard treatment is partial nephrectomy unless the patient has significant co-morbidities when surveillance or ablative therapies are utilised. The latter are relatively novel and their long-term efficacy and safety remain generally poorly understood. We performed a literature review to establish the current evidence on the oncological outcome of thermal ablative techniques in small renal masses treatment.

METHODS AND RESULTS

A systematic literature search was performed using PubMed, supplemented with additional references. Articles were reviewed for data on indications, tumour characteristics, ablative techniques, oncological outcome, impact on renal function and complications. The vast majority of articles identified were observational studies. There has not been any direct comparison against partial nephrectomy. Radiofrequency ablation and cryoablation are the techniques that are more commonly used. They have favourable oncological results on intermediate follow-up and indications that successful outcome is sustained long term. The morbidity and impact on renal function appear to be minimal.

CONCLUSION

Thermal ablative therapies are valid alternatives to partial nephrectomy for the treatment of small renal masses in patients unfit for surgery. Prospective long-term data will be needed before the indications for their use expand further.

Percutaneous radiofrequency ablation of renal cell carcinomas in patients with von Hippel Lindau disease: indications, techniques, complications, and outcomes

Renal cell carcinoma (RCC) in patients with von Hippel Lindau (VHL) disease tends to be multifocal, bilateral, and recur or develop new tumors after removal. These characteristics make treating hereditary RCCs difficult for urologists or radiologists compared to treating a sporadic RCC. Radiofrequency ablation (RFA) is a minimally-invasive treatment for small hereditary RCCs associated with a low complication rate and a minimal decrease in renal function. No RFA guidelines have been established about what to treat and when and how to ablate RCCs in patients with VHL disease. Besides, reports on complications and treatment outcomes in this patient group are rare. The purpose of this review is to discuss the indications, techniques, complications, and outcomes of RFA in treating RCC in patients with VHL disease.

Thermal ablation in renal cell carcinoma: what affects renal function?

Because of its minimally invasive nature, thermal ablation is increasingly performed in patients with renal cell carcinoma (RCC) who are poor surgical candidates. Thermal ablation has been associated with excellent outcomes, and thus has been regarded as a viable alternative to nephron-sparing surgery. Many papers report minimal to no reduction in renal function after ablation therapies. However, in order to achieve good local control, normal renal tissue must be sacrificed, subsequently leading to reduced renal function. The amount of normal renal tissue to be ablated depends on the size, location, and number of RCCs, as well as the type of thermal ablation applied. However, there are few reports about what reduces renal function following thermal ablation therapies. The purpose of this review was to discuss factors that affect reduction in renal function and to assess the relationship between local tumour control and renal function.

Laparoscopic cryoablation of renal masses: single-center long-term experience

OBJECTIVE

To evaluate perioperative and long-term functional and oncological outcomes of laparoscopic cryoablation (LCA) performed at Washington University.

METHODS

A retrospective chart review was performed evaluating 62 consecutive patients who underwent LCA at our institution between 2000 and 2005.

RESULTS

Mean age-adjusted Charlson Comorbidity Index (CCI) was 6.1 (SD, 2.1; 95% confidence interval [CI], 5.6-6.6). Mean tumor size was 2.52 cm (SD, 0.99; CI, 2.3-2.8). Mean operative time was 162.0 minutes (SD, 66.6; CI, 142.0-182.1). Mean estimated blood loss was 84.9 mL (SD, 102; CI, 58.6-111.2). Mean hospital stay was 2.6 days (SD, 1.90; CI, 2.1-3.1). The perioperative complication rate was 9.7% (Clavien 1-2). Among patients with biopsy proven, localized renal cell carcinoma, the 6-year Kaplan-Meier estimated disease-free survival (DFS) was 80%; cancer-specific survival (CSS) was 100%; and overall survival (OS) was 76.2%. Mean follow-up in this subset was 76.0 months (SD, 39.3; CI, 62.7-89.4; n = 35), whereas mean time to cancer recurrence was 27.6 months (SD, 11.2; CI, 15.9-39.3; n = 6). Tumor size ≥2.6 cm was the only predictor of cancer recurrence in a multivariate Cox proportional hazards model (hazard ratio [HR] = 28.9; P = .046; n = 35). Mean preoperative estimated glomerular filtration rate (eGFR) was 68.3 (SD, 22.3; CI, 62.1-74.5), compared to 64.5 mL/min/1.73 m(2) (SD, 28.9; CI, 56.5-72.6) at last follow-up (P = .12; n = 52). Excluding patients requiring secondary ablative or extirpative treatments for recurrent renal cell carcinoma, preoperative eGFR <60 mL/min/1.73 m(2) (odds ratio [OR] = 88.3; P = .036) and age-adjusted CCI ≥6 (OR = 32.4; P = .046) were the only factors predicting renal disease progression on multiple logistic regression (n = 47).

CONCLUSION

We report what is by far the longest follow-up to date of postlaparoscopic cryoablation changes in eGFR and note excellent long-term renal functional outcomes. For those willing to accept the potential need for retreatment for recurrent disease, LCA offers excellent long-term CSS.

Renal function outcomes in patients treated with partial nephrectomy versus percutaneous ablation for renal tumors in a solitary kidney

PURPOSE

Partial nephrectomy is the recommended management for small renal masses. Percutaneous ablation is safe and effective with comparable short-term cancer specific survival. Currently to our knowledge data are lacking on the impact of thermal ablation on renal function preservation. We examined the impact on renal function of partial nephrectomy vs percutaneous ablation in patients with a solitary kidney.

MATERIALS AND METHODS

We performed a retrospective review to identify patients with a solitary kidney who underwent partial nephrectomy or percutaneous ablation at Mayo Clinic Rochester between 2003 and 2009. Preoperative characteristics and 3-month posttreatment renal function were compared using the Wilcoxon rank sum, chi-square and Fisher exact tests.

RESULTS

During the study period 50 patients underwent percutaneous ablation and 62 underwent partial nephrectomy. At partial nephrectomy no ischemia was used in 30 cases (48%), a median of 28 minutes of cold ischemia was used in 26 (42%) and a median of 18 minutes of warm ischemia was used in 6 (10%). Patients who underwent partial nephrectomy were younger (median age 62.5 vs 68.5 years, p = 0.01) and harbored larger tumors (median 3.5 vs 2.5 cm, p = 0.005) with higher nephrometry scores (median 9 vs 7, p = 0.03). At 3-month posttreatment followup no differences were noted between the 2 groups in glomerular filtration rate (p = 0.91), change in glomerular filtration rate (p = 0.77) or change in chronic kidney disease stage (p = 0.87). Similar results were observed when adjusting for age, tumor size and nephrometry score on multivariate analysis.

CONCLUSIONS

With judicious use of ischemia partial nephrectomy, even for more complex tumors, has short-term renal function outcomes similar to those of percutaneous ablation.

The importance of nephron-sparing focal therapy: renal function preservation

Historically, renal cancer has been treated with radical nephrectomy. Consequently, many patients developed renal insufficiency and the health problems associated with this. With the increasing diagnosis of small renal masses, nephron-sparing treatments have been developed to treat these masses adequately, while maximizing renal function. Focal ablative therapy is a means to treat small renal masses in a minimally invasive manner. Yet, there are few studies that have focused on their ability to preserve renal function. In this article, we review the existing literature on the renal function outcomes of patients treated with either radio frequency ablation or cryoablation.