Ten-Year Experience with Percutaneous Cryoablation of Renal Tumors: Tumor Size Predicts Disease Progression

Stage IA papillary and chromophobe renal cell carcinoma: effectiveness of cryoablation and partial nephrectomy

OBJECTIVES

To evaluate the effectiveness of cryoablation compared to partial nephrectomy in patients with stage IA papillary and chromophobe renal cell carcinoma (pRCC; chRCC).

MATERIAL AND METHODS

The 2004-2016 National Cancer Database was queried for adult patients with stage IA pRCC or chRCC treated with cryoablation or partial nephrectomy. Patients receiving systemic therapy or radiotherapy, as well as those with bilateral RCC or prior malignant disease were excluded. Overall survival (OS) was assessed using Kaplan-Meier plots and Cox proportional hazard regression models. Nearest neighbor propensity matching (1:1 cryoablation:partial nephrectomy, stratified for pRCC and chRCC) was used to account for potential confounders.

RESULTS

A total of 11122 stage IA renal cell carcinoma patients were included (pRCC 8030; chRCC 3092). Cryoablation was performed in 607 (5.5%) patients, and partial nephrectomy in 10515 (94.5%) patients. A higher likelihood of cryoablation treatment was observed in older patients with non-private healthcare insurance, as well as in those with smaller diameter low-grade pRCC treated at non-academic centers in specific US geographic regions. After propensity score matching to account for confounders, there was no statistically significant difference in OS comparing cryoablation vs partial nephrectomy in patients with pRCC (HR = 1.3, 95% CI: 0.96-1.75, p = 0.09) and those with chRCC (HR = 1.38, 95% CI: 0.67-2.82, p = 0.38).

CONCLUSION

After accounting for confounders, cryoablation, and partial nephrectomy demonstrated comparable OS in patients with stage IA papillary and chromophobe RCC. Cryoablation is a reasonable treatment alternative to partial nephrectomy for these histological RCC subtypes when radiologically suspected or diagnosed after biopsy.

CRITICAL RELEVANCE STATEMENT

Cryoablation might be considered as an upfront treatment alternative to partial nephrectomy in patients with papillary and chromophobe stage IA renal cell carcinoma, as both treatment approaches yield comparable oncological outcomes.

KEY POINTS

The utilization of cryoablation for stage IA papillary and chromophobe RCC increases. In the National Cancer Database, we found specific patterns of use of cryoablation. Cryoablation and partial nephrectomy demonstrate comparable outcomes after accounting for confounders.

The evolving management of small renal masses

Small renal masses (SRMs) are a heterogeneous group of tumours with varying metastatic potential. The increasing use and improving quality of abdominal imaging have led to increasingly early diagnosis of incidental SRMs that are asymptomatic and organ confined. Despite improvements in imaging and the growing use of renal mass biopsy, diagnosis of malignancy before treatment remains challenging. Management of SRMs has shifted away from radical nephrectomy, with active surveillance and nephron-sparing surgery taking over as the primary modalities of treatment. The optimal treatment strategy for SRMs continues to evolve as factors affecting short-term and long-term outcomes in this patient cohort are elucidated through studies from prospective data registries. Evidence from rapidly evolving research in biomarkers, imaging modalities, and machine learning shows promise in improving understanding of the biology and management of this patient cohort.

Renal Function After CT-Guided Cryoablation of Small Renal Tumours in Patients with Solitary Kidney: An Analysis of European Multinational Prospective EuRECA Registry

PURPOSE

Treatment of renal cell carcinoma (RCC) in patients with solitary kidneys remains challenging. The purpose of this multicentre cohort study was to explore how renal function is affected by percutaneous image-guided cryoablation in patients with solitary kidneys.

MATERIAL AND METHODS

Data from the European Registry for Renal Cryoablation database were extracted on patients with RCC in solitary kidneys treated with image-guided, percutaneous cryoablation. Patients were excluded if they had multiple tumours, had received previous treatment of the tumour, or were treated with more than one cryoablation procedure. Pre- and post-treatment eGFR (within 3 months of the procedure) were compared.

RESULTS

Of 222 patients with solitary kidneys entered into the database, a total of 70 patients met inclusion criteria. The mean baseline eGFR was 55.8 ± 16.8 mL/min/1.73 m2, and the mean 3-month post-operative eGFR was 49.6 ± 16.5 mL/min/1.73 m2. Mean eGFR reduction was - 6.2 mL/min/1.73 m2 corresponding to 11.1% (p = 0.01). No patients changed chronic kidney disease group to severe or end-stage chronic kidney disease (stage IV or V). No patients required post-procedure dialysis.

CONCLUSION

Image-guided renal cryoablation appears to be safe and effective for renal function preservation in patients with RCC in a solitary kidney. Following cryoablation, all patients had preservation of renal function without the need for dialysis or progression in chronic kidney disease stage despite the statistically significant reduction in eGFR. LEVEL OF EVIDENCE 3: Observational study.

Comparison of aggressiveness in central versus peripheral T1a clear-cell renal cell carcinoma

PURPOSE

This study aimed to estimate the difference between peripheral and central small renal lesions in terms of their oncologic potential.

METHODS

Cross-sectional retrospective analysis of patients with small renal masses (T1a) who underwent surgical treatment between January 2008 and July 2019 at the affiliated hospital. Only patients with ccRCC pathology were included. Cases were divided into 2 groups depending on tumor location (central or peripheral) based on the R.E.N.A.L and local nephrometry scoring. Presence of nodal involvement, distant metastases, ISUP grade and endophytic growth were defined as aggressiveness predictors. Statistical analyses was performed using a standard statistical software (IBM SPPS Statistics Ver. 22), with P < 0.05 considered statistically significant. Associations between tumor location and Fuhrman grade, exo-/endophytic growth, TNM classification, and type of operation were tested using the Pearson χ² test and 1-way ANOVA test.

RESULTS

Patients with centrally located tumors had a higher incidence of clinical and pathological lymph node involvement (P = 0.02, χ2 = 5.1). Patients in both groups had an equal number of distant metastases at the time of diagnosis (P = 0.3, χ2 = 0.8). The operation time was significantly longer in patients with central lesions, which obviously showed higher tumor complexity in this group (P < 0.005). Pathological evaluation revealed differences between ISUP grades in both groups (P < 0.005, χ2 = 29.9). Central masses were characterized by higher aggressiveness, indicating a worse prognosis. Furthermore, the cases in the first group were more often endophytic (P = 0.03, χ2 = 0.9). Nevertheless, this did not affect the surgical strategy in most cases with a tendency toward partial nephrectomy. Eventually, organ-sparing treatment was preferable in both groups (P = 0.13, χ2 = 2.29).

CONCLUSION

Centrally located kidney cancer has showed in present study a higher incidence of high ISUP grade, regional nodal involvement and endophytic growth type. Endophytic growth type was associated with worse ISUP grading. Distribution of ISUP grade was not age depended, thus showing no difference by this criterion, when comparing different age groups. Higher ISUP grade was strongly associated with presence of distant metastases in T1a kidney tumors. Further analysis is needed to investigate aggressiveness of centrally located T1a RCC, as it may influence current conservative management options.

MRI- Versus CT-Guided Renal Tumor Cryoablation: Is There a Difference?

PURPOSE

To compare procedure-related variables, safety, renal function, and oncologic outcomes in patients undergoing percutaneous cryoablation (CA) of renal tumors with MRI- or CT-guidance.

MATERIALS AND METHODS

Patient, tumour, procedure, and follow-up data were collected and analysed. MRI and CT groups were matched using a coarsened exact approach according to patient's gender and age, tumour grade, size and location. P < 0.05 was considered statistically significant.

RESULTS

Two-hundred fifty-three patients (266 tumors) were retrospectively selected. Following the coarsened exact matching 46 patients (46 tumors) in the MRI group and 42 patients (42 tumors) in the CT group were matched. There were no significant baseline differences between the two populations except for the duration of follow-up (P = 0.002) and renal function (P = 0.002). On average MRI-guided CA lasted 21 min longer than CT-guided ones (P = 0.005). Following CA, complication rates (6.5% for MRI vs 14.3% for CT; P = 0.30) and GFR decline (mean - 13.1 ± 15.8%; range - 64.5-15.0 for MRI; mean - 8.1 ± 14.8%; range - 52.5-20.4; for CT; P = 0.13) were similar in both groups. The 5-year local progression-free, cancer-specific and overall survivals in the MRI and CT groups were 94.0% (95% CI 86.3%-100.0%) and 90.8% (95% CI 81.3%-100.0%; P = 0.55), 100.0% (95% CI 100.0%-100.0%) and 100.0% (95% CI 100.0%-100.0%; P = 1), and 83.7% (95% CI 64.0%-100.0%) and 76.2% (95% CI 62.0%-93.6%; P = 0.41), respectively.

CONCLUSIONS

Apart from increased procedural times associated with MRI-guided CA of renal tumors compared to CT-guidance, both modalities demonstrate similar safety, GFR decline and oncologic outcomes.

Focal Cryo-Immunotherapy with Intratumoral IL-12 Prevents Recurrence of Large Murine Tumors

Focal ablation technologies are routinely used in the clinical management of inoperable solid tumors but they often result in incomplete ablations leading to high recurrence rates. Adjuvant therapies, capable of safely eliminating residual tumor cells, are therefore of great clinical interest. Interleukin-12 (IL-12) is a potent antitumor cytokine that can be localized intratumorally through coformulation with viscous biopolymers, including chitosan (CS) solutions. The objective of this research was to determine if localized immunotherapy with a CS/IL-12 formulation could prevent tumor recurrence after cryoablation (CA). Tumor recurrence and overall survival rates were assessed. Systemic immunity was evaluated in spontaneously metastatic and bilateral tumor models. Temporal bulk RNA sequencing was performed on tumor and draining lymph node (dLN) samples. In multiple murine tumor models, the addition of CS/IL-12 to CA reduced recurrence rates by 30-55%. Altogether, this cryo-immunotherapy induced complete durable regression of large tumors in 80-100% of treated animals. Additionally, CS/IL-12 prevented lung metastases when delivered as a neoadjuvant to CA. However, CA plus CS/IL-12 had minimal antitumor activity against established, untreated abscopal tumors. Adjuvant anti-PD-1 therapy delayed the growth of abscopal tumors. Transcriptome analyses revealed early immunological changes in the dLN, followed by a significant increase in gene expression associated with immune suppression and regulation. Cryo-immunotherapy with localized CS/IL-12 reduces recurrences and enhances the elimination of large primary tumors. This focal combination therapy also induces significant but limited systemic antitumor immunity.

Intraoperative MRI-derived volumetric ablation margins and initial correlation with local outcome after MRI-guided cryoablation of renal tumors

PURPOSE

To assess volumetric ablation margins derived from intraoperative pre- and post-ablation MRI after magnetic resonance imaging (MRI)-guided percutaneous cryoablation of renal tumors and explore its correlation with local treatment success.

METHODS

Retrospective analysis was performed on 30 patients (mean age 69y) who underwent percutaneous MRI-guided cryoablation between May 2014 and May 2020 for 32 renal tumors (size: 1.6-5.1 cm). Tumor and ice-ball volumes were segmented on intraprocedural pre- and post-ablation MR images using Software Assistant for Interventional Radiology (SAFIR) software. After MRI-MRI co-registration, the software automatically quantified the minimal treatment margin (MTM),defined as the smallest 3D distance between the tumor and ice-ball surface. Local tumor progression (LTP) after cryoablation was assessed on follow-up imaging.

RESULTS

Median follow-up was 16 months (range: 1-58). Local control after cryoablation was achieved in 26 cases (81%) while LTP occurred in 6 (19%). The intended MTM of ≥5 mm was achieved in 3/32 (9%) cases. Median MTM was significantly smaller for cases with (- 7 mm; IQR:-10 to - 5) vs. without LTP (3 mm; IQR:2 to 4) (P < .001). All cases of LTP had a negative MTM. All negative treatment margins occurred in tumors > 3 cm.

CONCLUSIONS

Determination of volumetric ablation margins from intraoperative MRI was feasible and may be useful in predicting local outcome after MRI-guided renal cryoablation. In our preliminary data, an intraoperative MRI-derived minimal margin extending at least 1 mm beyond the MRI-visible tumor led to local control and this was more difficult to achieve in tumors > 3 cm. Ultimately, online margin analysis may be a valuable tool to intraoperatively assess therapy success, but larger prospective studies are needed to establish a reliable threshold for clinical use.

Safety, efficacy, and mid-term oncological outcomes of computed tomography-guided cryoablation of T1 renal cancer

BACKGROUND

Cryoablation is a promising minimally invasive, nephron-sparing treatment of small renal carcinoma (RCC) in co-morbid patients.

PURPOSE

To assess the safety, efficacy, and cancer-specific outcomes of computed tomography (CT)-guided cryoablation of stage T1 (RCC).

MATERIAL AND METHODS

A retrospective evaluation of 122 consecutive patients with 128 tumors treated with cryoablation during 2016-2017. All patients had biopsy-verified T1 RCC.

RESULTS

Median age was 69 years (IQR=59-76); 69% were male. Median tumor size was 26 mm (± 20-33); 9% were stage T1b. Mean follow-up time was 36.3±12.0 months. In total, 14 (11%) procedures led to complications, of which 4 (3%) were intraoperative, 5 (4%) appeared ≤30 days and 5 (4%) >30 days after treatment. Major complications arose after 4 (3%) procedures. Statistically significant associations were found between major complications and stage T1b (P = 0.039), RENAL score (P = 0.010), and number of needles used in cryoablation (P = 0.004). Residual tumor was detected after 4 (3%) procedures and 5 (4%) tumors had local tumor progression. Of 122 patients, 3 (2%) advanced to metastatic disease. Significant statistical associations were found between local tumor progression and T1b stage tumors and number of needles used in cryoablation (P = 0.05 and P = 0.004, respectively). For patients with T1a tumors, the one- and three-year disease-free survival was 98% and 95%, respectively, and for T1b 100% after one year and 75% after three years.

CONCLUSIONS

This study showed that cryoablation is a safe and effective treatment of stage T1 RCC and suggests that in selecting candidates for cryoablation of RCC, the tumor characteristics are more critical than patients' baseline health status.

Prognostic Significance of Advanced Age in Patients with T1a Renal Cell Carcinoma Treated by Microwave Ablation: A 16-Year Experience

BACKGROUND

Previous studies have failed to investigate the specific effects of advanced age on survival outcomes by considering the Charlson Comorbidity Index (CCI) and age permutation in patients with T1a renal cell carcinoma (T1a RCC) treated by microwave ablation (MWA). Notably, RCC guidelines recommended radiofrequency ablation (RFA) and active surveillance (AS) are both treatment options for elderly T1a RCC, but whether MWA is superior to AS in light of higher heating efficiency and larger ablation zone compared with RFA is not clear. This study aimed to investigate the specific effects of advanced age on survival outcomes of T1a RCC patients stratified by CCI score and indicate better intervention for elderly T1a RCC between MWA and AS.

METHODS

This was a retrospective study. We retrospectively reviewed 237 patients with T1a RCC who had undergone MWA over the last 16 years. Data were analyzed by Cox regression and Landmark analysis. Interaction tests and propensity score matching were used to account for potential biases. We compared the overall survival (OS) and cancer-specific survival (CSS) rates of patients ≥75 years in our study with corresponding figures from 4251 counterparts undergoing AS in published articles.

RESULTS

Using patients ＜75 years with a CCI ≤2 as a reference, the hazard ratio (HR) and 95% confidence interval (CI) of OS for patients＜75 years with a CCI ≥3, patients ≥75 years with a CCI ≤2, and patients ≥75 years with CCI ≥3, were 2.954 (1.139-7.663), 3.48 (1.487-8.146), and 3.357 (1.162-9.698), respectively. The adverse effect of an age ≥75 years on OS was attenuated in patients with a CCI ≥3. The attenuation lasted for 62.5 months of follow-up (P = .017). Notably, advanced age exerted a protective effect on progression-free survival (PFS) in patients with a CCI ≥3, increasing the 8-year PFS from 67.8% to 100% (P = .049). Relative to 1-, 3-, 5-, and 8-year survival data for patients aged ≥75 undergoing AS, the OS rates for 5-year follow-up were always better in MWA. However, beyond 5 years, the OS rates dropped to levels that were similar to AS.

CONCLUSIONS

Advanced age exerts adverse effects and significantly protective effects on OS and PFS, respectively, in T1a RCC patients with a CCI ≥ 3. According to our study, elderly patients with T1a RCC underwent radical MWA may yield a better medium-term OS relative to AS.

Thermal ablation for small renal masses: Identifying the most appropriate tumor size cut-off for predicting perioperative and oncological outcomes

OBJECTIVES

To test TRIFECTA achievement [1) absence of CLAVIEN-DINDO ≥3 complications; 2) complete ablation; 3) absence of ≥30% decrease in eGFR] and local recurrence rates, according to tumor size, in patients treated with thermal ablation (TA: radiofrequency [RFA] and microwave ablation [MWA]) for small renal masses.

METHODS

Retrospective analysis (2008-2020) of 432 patients treated with TA (RFA: 162 vs. MWA: 270). Tumor size was evaluated as: 1) continuously coded variable (cm); 2) tumor size strata (0.1-2 vs. 2.1-3 vs. 3.1-4 vs. >4 cm). Multivariable logistic regression models and a minimum P-value approach were used for testing TRIFECTA achievement. Kaplan-Meier plots depicted local recurrence rates over time.

RESULTS

Overall, 162 (37.5%) vs. 140 (32.4%) vs. 82 (19.0%) vs. 48 (11.1%) patients harboured, respectively, 0.1 to 2 vs. 2.1 to 3 vs. 3.1 to 4 vs. >4 cm tumors. In multivariable logistic regression models, increasing tumor size was associated with higher rates of no TRIFECTA achievement (OR:1.11; P< 0.001). Using a minimum P-value approach, an optimal tumor size cut-off of 3.2 cm was identified (P< 0.001). In multivariable logistic regression models, 3.1 to 4 cm tumors (OR:1.27; P< 0.001) and >4 cm tumors (OR:1.49; P< 0.001), but not 2.1 to 3 cm tumors (OR:1.05; P= 0.3) were associated with higher rates of no TRIFECTA achievement, relative to 0.1 to 2 cm tumors. The same results were observed in separate analyses of RFA vs. MWA patients. After a median (IQR) follow-up time of 22 (12-44) months, 8 (4.9%), 8 (5.7%), 11 (13.4%), and 5 (10.4%) local recurrences were observed in tumors sized 0.1 to 2 vs. 2.1 to 3 vs. 3.1 to 4 vs. >4 cm, respectively (P= 0.01).

CONCLUSION

A tumor size cut-off value of ≤3 cm is associated with higher rates of TRIFECTA achievement and lower rates of local recurrence over time in patients treated with TA for small renal masses.

The Role of Focal Therapy and Active Surveillance for Small Renal Mass Therapy

Small and low-grade renal cell carcinomas have little potential for metastasis and disease-related mortality. As a consequence, the main problem remains the use of appropriately tailored treatment for each individual patient. Surgery still remains the gold standard, but many clinicians are questioning this approach and present the advantages of focal therapy. The choice of treatment regimen remains a matter of debate. This article summarizes the current treatment options in the management of small renal masses.

Overview of clinical management for older patients with renal cell carcinoma

The rapidly increasing pool of older patients being diagnosed with and surviving their cancer is creating many challenges. Regarding localized renal cell carcinoma, surgery is considered as gold standard treatment options even in older men, whereas active surveillance and ablation therapy are alternative options for a proportion of these patients. With regard to advanced disease, anti-vascular endothelial growth factor tyrosine kinase inhibitors (VEGFR-TKI) and immune check point inhibitor are standard treatment modalities, although treatment choice from multiple regimens and prevention of adverse events need to be considered. Better assessment techniques, such as comprehensive geriatric assessment to meet the unique needs of older patients, are a central focus in the delivery of high-quality geriatric oncology care. Through this process, shared decision-making should be adopted in clinical care to achieve optimal goals of care that reflect patient and caregiver hopes, needs and preferences. It is necessary to continue investigating oncological outcomes and complications associated with treatment in this population to ensure appropriate cancer care. In this narrative review, we completed a literature review of the various treatments for renal cell carcinoma in older patients that aimed to identify the current evidence related to the full range of the treatments including active surveillance, surgery, ablation therapy and systemic therapy. Prospectively designed studies and studies regarding geriatric assessment were preferentially added as references. Our goals were to summarize the real-world evidence and provide a decision framework that guides better cancer practices for older patients with renal cell carcinoma.