Update on Cryoablation for Treatment of Small Renal Mass: Oncologic Control, Renal Function Preservation, and Rate of Complications

Urinoma formation following renal mass cryoablation treated with nephroureteral stent placement

Renal cryoablation (CA) has become an accepted treatment option for patients with small renal tumors and co-morbidities that make them less favorable for surgical intervention. Complications from renal CA have been previously reported and are generally associated with increasing size and central location of the tumor. Ureteral injury from renal CA, although rare, can be difficult to manage and may require complex surgeries in patients who are poor surgical candidates to begin with. We report a case of a renal mass CA complicated by proximal ureteral necrosis and transection, treated with multiple minimally invasive procedures ultimately resulting in successful bridging of the necrotic segment with nephroureteral stent and thus avoiding major surgery.

Assessing Trifecta Achievement after Percutaneous Cryoablation of Small Renal Masses: Results from a Multi-Institutional Collaboration

Background and Objectives: To assess efficacy and safety of Percutaneous Cryoablation (PCA) of small renal masses (SRMs) using Trifecta outcomes in a large cohort of patients who were not eligible for surgery. Materials and methods: All PCAs performed in four different centers between September 2009 and September 2019 were retrospectively evaluated. Patients were divided in two different groups depending on masses dimensional criteria: Group-A: diameter ≤ 25 mm and Group-B: diameter > 25 mm. Complications rates were reported and classified according to the Clavien−Dindo system. The estimate glomerular filtration rate (eGFR) was calculated before PCA and during follow-up schedule. Every patient received a Contrast Enhanced Ultrasound (CEUS) evaluation on the first postoperative day. Radiological follow-up was taken at 3, 6, and 12 months for the first year, then yearly. Radiological recurrence was defined as a contrast enhancement persistence and was reported in the study. Finally, Trifecta outcome, which included complications, RFS, and preservation of eGFR class, was calculated for every procedure at a median follow-up of 32 months. Results: The median age of the patients was 74 years. Group-A included 200 procedures while Group-B included 140. Seventy-eight patients were eligible for Trifecta evaluation. Trifecta was achieved in 69.6% of procedures in Group-A, 40.6% in Group-B (p = 0.02). We observed an increased rate of complication in Group-B (13.0% vs. 28.6; p < 0.001). However, 97.5% were <II Clavien−Dindo grade. No differences were found between the two groups regarding eGFR before and after treatment. Further, 24-months RFS rates were respectively 98.0% for Group-A and 92.1% in Group-B, while at 36 months were respectively 94.5% and 87.5% (p = 0.08). Conclusions: PCA seems to be a safe and effective treatment for SRM but in the need of more strict dimensional criteria to achieve a higher possible success rate.

Percutaneous Cryoablation versus Robot-Assisted Partial Nephrectomy of Renal T1A Tumors: a Single-Center Retrospective Cost-Effectiveness Analysis

PURPOSE

To evaluate the cost-effectiveness of percutaneous cryoablation (PCA) versus robot-assisted partial nephrectomy (RPN) in patients with small renal tumors (T1a stage), considering perioperative complications.

MATERIALS AND METHODS

Retrospective study from November 2008 to April 2017 of 122 patients with a T1a renal mass who after being analyzed by a multidisciplinary board underwent to PCA (59 patients) or RPN (63 patients). Hospital costs in US dollars, and clinical and tumor data were compared. Non-complicated intervention was considered as an effective outcome. A hypothetical model of possible complications based on Clavien-Dindo classification (CDC) was built, grouping them into mild (CDC I and II) and severe (CDC III and IV). A decision tree model was structured from complications of published data.

RESULTS

Patients who underwent PCA were older (62.5 vs. 52.8 years old, p < 0.001), presented with more coronary disease and previous renal cancer (25.4% vs. 10.1%, p = 0.023 and 38% vs. 7.2%,  p < 0.001, respectively). Patients treated with PCA had a higher preoperative risk (American Society of Anesthesiologists-ASA ≥ 3) than those in the RPN group (25.4% vs. 0%, p < 0.001). Average operative time was significantly lower with PCA than RPN (99.92 ± 29.05 min vs. 129.28 ± 54.85 min, p < 0.001). Average hospitalization time for PCA was 2.2 ± 2.95 days, significantly lower than RPN (mean 3.03 ± 1.49 days, p = 0.04). The average total cost of PCA was significantly lower than RPN (US$12,435 ± 6,176 vs. US$19,399 ± 6,047, p < 0.001). The incremental effectiveness was 5% higher comparing PCA with RPN, resulting a cost-saving result in favor of PCA.

CONCLUSION

PCA was the dominant strategy (less costly and more effective) compared to RPN, considering occurrence of perioperative complications.

Cryoablation: a potential treatment option for renal metastasis from lung cancer?

Cryoablation is successfully performed as a treatment for small renal cancers. The occurrence of a solitary renal metastasis from lung cancer is an uncommon finding entailing a limited knowledge on the choice of its optimal treatment. We present two patients diagnosed with non-small cell lung cancer, who were initially treated with curatively intended chemoradiotherapy. In the follow-up period, a non-symptomatic solitary renal metastasis was found in both patients. Both received CT-guided cryoablation of their renal metastases. One patient was successfully treated with no relapse, whereas the other patient received re-cryoablation due to development of a new renal metastasis. In both patients, no residual tumour was found at the 3 months' follow-up examination. Whether the minimally invasive procedure of cryoablation is a feasible treatment in the management of solitary renal metastases from lung cancer is still undetermined. The recurrence and incomplete treatment are concerns requiring further research.

Arterial Clamping Increases Central Renal Cryoablation Efficacy: An Animal Study

INTRODUCTION

The minimally invasive treatment of small renal masses with cryoablation has become increasingly widespread during the past 15 years. Studies with long-term follow-up are beginning to emerge, showing good oncological control, however, tumors with a central and endophytic location seem to possess an increased risk of treatment failure. Such tumors are likely to be subjected to a high volume of blood giving thermal protection to the cancerous cells. Arterial clamping during freezing might reduce this effect but at the same time subject the kidney to ischemia. The aim of this study was to evaluate the effect of renal artery clamping during cryoablation in a porcine survival model.

METHODS

Ten Danish Landrace pigs (approximately 40 kg) underwent bilateral laparoscopic cryoablation with clamping of the right renal artery during freezing. The cryoablation consisted of a standard double-freeze cycle of 10-minute freeze followed by 8 minutes of thaw. Arterial clamping subjected the right kidney to 2 cycles of ischemia (10 minutes) with perfusion in between. After surgery, the animals were housed for 14 days prior to computed tomography perfusions scans, radioisotope renography, and bilateral nephrectomy.

RESULTS

No perioperative or postoperative complications were experienced. Mean differential renal function was 44% (95% confidence interval: 42-46) in the clamped right kidney group and 56% (95% confidence interval: 54-58) in the nonclamped left kidney group, P < .05. The ±5% technical inaccuracy is not accounted for in the results. Mean maximum temperature between freeze cycles was 5.13°C (95% confidence interval: -0.1 to 10.3) in the clamped right kidney group and 22.7°C (95% confidence interval: -16.6 to 28.8) in the nonclamped left kidney group, P < .05. Mean cryolesion volume, estimated on computed tomography perfusion, was 12.4 mL (95% confidence interval: 10.35-14.4) in the clamped right kidney group and 6.85 mL (95% confidence interval: 5.57-8.14) in the nonclamped left kidney group, P < .05. Pathological examination shows a higher degree of vital cells in the intermediate zone of the cryolesions in the nonclamped left kidneys when compared with the clamped right kidneys.

CONCLUSION

Arterial clamping increases cryolesion size by approximately 80%, and pathologic examinations suggest a decreased risk of vital cells in the intermediate zone. The clamped kidneys showed no sign of injury from the limited ischemic insult. This study was limited by being a nontumor model.

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.

Molecular aberrations, targeted therapy, and renal cell carcinoma: current state-of-the-art

Renal cell carcinoma (RCC) is among the most prevalent malignancies in the USA. Most RCCs are sporadic, but hereditary syndromes associated with RCC account for 2-3 % of cases and include von Hippel-Lindau, hereditary leiomyomatosis, Birt-Hogg-Dube, tuberous sclerosis, hereditary papillary RCC, and familial renal carcinoma. In the past decade, our understanding of the genetic mutations associated with sporadic forms of RCC has increased considerably, with the most common mutations in clear cell RCC seen in the VHL, PBRM1, BAP1, and SETD2 genes. Among these, BAP1 mutations are associated with aggressive disease and decreased survival. Several targeted therapies for advanced RCC have been approved and include sunitinib, sorafenib, pazopanib, axitinib (tyrosine kinase inhibitors (TKIs) with anti-vascular endothelial growth factor (VEGFR) activity), everolimus, and temsirolimus (TKIs that inhibit mTORC1, the downstream part of the PI3K/AKT/mTOR pathway). High-dose interleukin 2 (IL-2) immunotherapy and the combination of bevacizumab plus interferon-α are also approved treatments. At present, there are no predictive genetic markers to direct therapy for RCC, perhaps because the vast majority of trials have been evaluated in unselected patient populations, with advanced metastatic disease. This review will focus on our current understanding of the molecular genetics of RCC, and how this may inform therapeutics.

Multidetector CT imaging of complications after laparoscopic nephron-sparing surgery

Purpose

Laparoscopic nephron-sparing surgery (L-NSS) is increasingly performed to treat localised renal lesions. However, the associated morbidity is non-negligible, with a rate of major complications approaching 10 %.

Methods and Results

This paper provides an overview of indications, surgical techniques and results of L-NSS; explains the incidence, risk factors and manifestations of postoperative complications; discusses the preferred multidetector computed tomography (CT) acquisition techniques; illustrates the appearance of normal postoperative images following L-NSS; and reviews, with example images, the most common and unusual iatrogenic complications. These include haematuria, haemorrhage, vascular injuries, infections and urinary leaks. Most emphasis is placed on CT, which provides rapid, reliable triage and follow-up of iatrogenic complications after L-NSS, identifying occurrences that require transarterial embolisation or repeated surgery.

Conclusions

Multidetector CT allows precise assessment of the surgical resection site; detection of pneumoperitoneum and subcutaneous emphysema; quantification of retroperitoneal blood; and identification of active bleeding, pseudoaneurysms, arterio-venous fistulas, abscess collections and extravasated urine.

Teaching Points

• Laparoscopic nephron-sparing surgery (NSS) is increasingly performed to treat renal lesions.

• Radiologists are increasingly requested to investigate suspected post-surgical NSS complications.

• Post-NSS complications include haemorrhage, haematuria, vascular injuries, infections and urinary leaks.

• Multidetector CT allows choice between conservative treatment, transarterial embolisation or surgery.

Percutaneous Cryoablation for Renal Cell Carcinoma

Renal cell carcinoma (RCC) is the most common type of kidney cancer in adults. Nephron sparing resection (partial nephrectomy) has been the “gold standard” for the treatment of resectable disease. With the widespread use of cross sectional imaging techniques, more cases of renal cell cancers are detected at an early stage, i.e. stage 1A or 1B. This has provided an impetus for expanding the nephron sparing options and especially, percutaneous ablative techniques. Percutaneous ablation for RCC is now performed as a standard therapeutic nephron-sparing option in patients who are poor candidates for resection or when there is a need to preserve renal function due to comorbid conditions, multiple renal cell carcinomas, and/or heritable renal cancer syndromes. During the last few years, percutaneous cryoablation has been gaining acceptance as a curative treatment option for small renal cancers. Clinical studies to date indicate that cryoablation is a safe and effective therapeutic method with acceptable short and long term outcomes and with a low risk, in the appropriate setting. In addition it seems to offer some advantages over radio frequency ablation (RFA) and other thermal ablation techniques for renal masses.