Percutaneous radiofrequency ablation for renal cell carcinoma vs. partial nephrectomy: Comparison of long-term oncologic outcomes in both clear cell and non-clear cell of the most common subtype

Image-Guided Ablation of Renal Masses: Challenges to Produce High-Quality Evidence and Future Directions

Image-guided ablation (IGA) is a rapidly developing field in interventional oncology. There is some evidence suggesting IGA's non-inferiority compared with partial or radical nephrectomy for the treatment of small renal masses (SRM). However, these are mostly limited to retrospective cohort studies. This review article outlines the evidence comparing IGA to partial nephrectomy by collating the different survival measures and evaluates the challenges of producing clinical trials and high-quality evidence. The main challenges are due to the heterogeneity of SRM, patient selection bias, unstandardized endpoint and outcomes, and the lack of global practice standards. Despite the evidence thus far demonstrating that IGA stands as a non-inferior treatment modality for SRMs, exhibiting favorable short- and long-term outcomes, further robust research is needed to integrate ablation techniques into routine clinical practice with a multidisciplinary approach. There is emerging evidence that suggests randomized controlled trial in SRMs is possible, and technologies such as histotripsy as well as artificial intelligence are used in IGA.

The long-term outcomes of local tumor destruction versus partial nephrectomy for cT1a non-clear cell renal cell carcinoma and development of prognostic nomograms

PURPOSE

There is a lack of authoritative opinions on local tumor destruction (LTD) for clinical T1a (cT1a) non-clear cell renal cell carcinoma (nccRCC). We aim to compare the outcomes of cT1a nccRCC after partial nephrectomy (PN) or LTD and explore prognostic factors.

METHODS

Patients diagnosed with cT1a nccRCC receiving LTD or PN between 2000 and 2020 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. A 1:1 propensity score matching (PSM) was performed for patients receiving LTD and PN. Kaplan-Meier survival analysis, Cox regression analysis, competing risk regression models, and subgroup analysis were used to compare outcomes and identify prognostic factors. Prognostic nomograms were established and evaluated based on the multivariate models.

RESULTS

A total of 3664 cT1a nccRCC patients were included. The LTD group had poorer overall survival (OS) and similar cancer-specific survival (CSS) compared with the PN group before and after PSM (p < 0.05), while the other-cause mortality rate of the LTD group was higher than that of the PN group. Age, marital status, household income, prior tumor history, interval between diagnosis and treatment, treatments, and tumor size were identified as independent predictive factors for OS. Age, tumor size, prior tumor history, and histological type were identified as independent predictive factors for CSS. Then the nomograms predicting OS and CSS were constructed based on these prognostic factors, which showed excellent performance in risk stratification and accuracy.

CONCLUSION

LTD could achieve comparable cancer-control effects as PN among cT1a nccRCC patients. The OS and CSS nomograms worked effectively for prognosis assessment.

Stereotactic body radiation therapy for kidney cancer. Where do we stand?

At present, surgery is still the gold standard for the local treatment of renal cancer. Nonetheless, in several clinical scenarios, stereotactic body radiation therapy (SBRT) also known as stereotactic ablative body radiotherapy (SABR) is emerging as a highly effective ablative technique in fragile patients and those with significant comorbidities, as well as in cases where percutaneous therapy (cryoablation or radiofrequency) is not viable. However, considering the intrinsic radioresistance of renal tumors, the optimal treatment schemes have not been established. In oligometastatic patients, it has been reported that the control of the oligometastases can be a potentially curable approach. Being a technique than can be administered exclusively or in combination with systemic therapy, treatment individualization based on patient characteristics is key. Another scenario under investigation is oligoprogression, where SBRT offers the possibility of delaying further lines of systemic therapy by eliminating subclones of resistant tumor with ablative doses, with the additional opportunity of stimulating the immune system (immunomodulatory role). In this review, we have conducted an analysis of recently published studies that test the role of this technique in different clinical scenarios of this disease. We have found promising results that make SBRT a potent therapeutic approach with low toxicity. We also comment on ongoing studies that will generate the necessary evidence needed for the implementation of this technique in our daily clinical practice.

Long-term outcomes of radiofrequency ablation vs. partial nephrectomy for cT1 renal cancer: A meta-analysis and systematic review

Background

Partial nephrectomy (PN) is one of the most preferred nephron-sparing treatments for clinical T1 (cT1) renal cancer, while radiofrequency ablation (RFA) is usually used for patients who are poor surgical candidates. The long-term oncologic outcome of RFA vs. PN for cT1 renal cancer remains undetermined. This meta-analysis aims to compare the treatment efficacy and safety of RFA and PN for patients with cT1 renal cancer with long-term follow-up of at least 5 years.

Method

This meta-analysis was performed following the PRISMA reporting guidelines. Literature studies that had data on the comparison of the efficacy or safety of RFA vs. PN in treating cT1 renal cancer were searched in databases including PubMed, Embase, Web of Science, and the Cochrane Library from 1 January2000 to 1 May 2022. Only long-term studies with a median or mean follow-up of at least 5 years were included. The following measures of effect were pooled: odds ratio (OR) for recurrence and major complications; hazard ratio (HR) for progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS). Additional analyses, including sensitivity analysis, subgroup analysis, and publication bias analysis, were also performed.

Results

A total of seven studies with 1,635 patients were finally included. The treatment efficacy of RFA was not different with PN in terms of cancer recurrence (OR = 1.22, 95% CI, 0.45-3.28), PFS (HR = 1.26, 95% CI, 0.75-2.11), and CSS (HR = 1.27, 95% CI, 0.41-3.95) as well as major complications (OR = 1.31, 95% CI, 0.55-3.14) (P > 0.05 for all). RFA was a potential significant risk factor for OS (HR = 1.76, 95% CI, 1.32-2.34, P < 0.001). No significant heterogeneity and publication bias were observed.

Conclusion

This is the first meta-analysis that focuses on the long-term oncological outcomes of cT1 renal cancer, and the results suggest that RFA has comparable therapeutic efficacy with PN. RFA is a nephron-sparing technique with favorable oncologic efficacy and safety and a good treatment alternative for cT1 renal cancer.

Treatment strategies for clear cell renal cell carcinoma: Past, present and future

Clear cell renal cell carcinoma (ccRCC) is the most prevalent histological subtype of kidney cancer, which is prone to metastasis, recurrence, and resistance to radiotherapy and chemotherapy. The burden it places on human health due to its refractory nature and rising incidence rate is substantial. Researchers have recently determined the ccRCC risk factors and optimized the clinical therapy based on the disease's underlying molecular mechanisms. In this paper, we review the established clinical therapies and novel potential therapeutic approaches for ccRCC, and we support the importance of investigating novel therapeutic options in the context of combining established therapies as a research hotspot, with the goal of providing diversified therapeutic options that promise to address the issue of drug resistance, with a view to the early realization of precision medicine and individualized treatment.

Differential efficacy of ablation therapy versus partial nephrectomy between clinical T1a and T1b renal tumors: A systematic review and meta-analysis

PURPOSE

To assess the differential clinical outcomes of patients treated with partial nephrectomy (PN) vs. those treated with ablation therapy (AT) such as radiofrequency ablation, cryoablation and microwave ablation for cT1b compared to cT1a renal tumors.

MATERIALS AND METHODS

Multiple databases were searched for articles published before August 2021. Studies were deemed eligible if they compared clinical outcomes in patients who underwent PN with those who underwent AT for cT1a and/or cT1b renal tumors.

RESULTS

Overall, 27 studies comprising 13,996 patients were eligible for this meta-analysis. In both cT1a and cT1b renal tumors, there was no significant difference in the percent decline of estimated glomerular filtration rates or in the overall/severe complication rates between PN and AT. Compared to AT, PN was associated with a lower risk of local recurrence in both patients with cT1a and cT1b tumors (cT1a: pooled risk ratio [RR]; 0.43, 95% confidence intervals [CI]; 0.28-0.66, cT1b: pooled RR; 0.41, 95%CI; 0.23-0.75). Subgroup analyses regarding the technical approach revealed no statistical difference in local recurrence rates between percutaneous AT and PN in patients with cT1a tumors (pooled RR; 0.61, 95%CI; 0.32-1.15). In cT1b, however, PN was associated with a lower risk of local recurrence (pooled RR; 0.45, 95%CI; 0.23-0.88). There was no difference in distant metastasis or cancer mortality rates between PN and AT in patients with cT1a, or cT1b tumors.

CONCLUSIONS

AT has a substantially relevant disadvantage with regards to local recurrence compared to PN, particularly in cT1b renal tumors. Despite the limitations inherent to the nature of retrospective and unmatched primary cohorts, percutaneous AT could be used as a reasonable alternative treatment for well-selected patients with cT1a renal tumors.

Diagnosis and Treatment of Small Renal Masses: Where Do We Stand?

PURPOSE OF REVIEW

To present an overview of the current evidence-based studies covering diagnostic and management of SRM.

RECENT FINDINGS

Renal cell carcinoma (RCC) represents 3% of the cancers. Nowadays, partial nephrectomy (PN) represents gold standard treatment. New nephron-sparing approaches such as active surveillance and ablative therapies have been increasingly used as an alternative to surgical intervention. Due to novel comprehension of RCC and widespread use of imaging techniques, diagnosis at early stage in elderly patients has increased. Treatment decision-making should be based on patient and tumour characteristics. With expanding treatment options, the management of SRMs has become a debate and should be adjusted to patient and tumour characteristics. In a shared decision manner, both active surveillance with possible delayed intervention and focal therapy should be discussed with the patient as an alternative to partial nephrectomy.

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.

Ablative therapies versus partial nephrectomy for small renal masses - A systematic review and meta-analysis

BACKGROUND

High quality studies and reviews on the management of small renal masses (SRM) are lacking. This review aims to compare oncological outcomes in patients undergoing ablative therapies (AT) or partial nephrectomy (PN) for T1a or T1b SRM.

MATERIAL AND METHODS

Medline, EMBASE, Cochrane CENTRAL and conference proceedings were searched on the 15th July 2020 for comparative studies respective to our research question. The ROBINS-I tool and the GRADE approach were used to assess any risk of biases and certainty of evidence in the included studies. The review is registered on PROSPERO.

RESULTS

1,748 records were retrieved. 32 observational studies and 1 RCT integrating 74,946 patients were included. Patients undergoing AT patients are significantly older than PN patients (MD 5.70, 95%CI 3.83-7.58). In T1a patients, AT patients have significantly worse overall survival (HR 1.64, 95%CI 1.39-1.95). Local recurrence-free survival is similar with PN in patients with longer than five-years follow up (HR 1.54, 95%CI 0.88-2.71). AT patients also have similar cancer-specific survival (CSS), metastasis-free survival, disease-free survival, significantly fewer post-operative complications (RR 0.72, 95%CI 0.55-0.94), and a smaller decline in estimated glomerular filtration rate post-operatively (MD: -7.42, 95%CI -13.1 to -1.70) compared to those undergoing PN. Evidence contradicts in T1b patients for oncological outcomes.

CONCLUSIONS

AT have similar long-term oncological durability; lower rates of complications and superior kidney function preservation compared to PN. Given the low quality of evidence, AT is a reasonable alternative to PN in frail and co-morbid patients. Long-term high-quality studies are needed to confirm the potential benefits of AT, especially in T1b patients.

PROSPERO REGISTRATION

CRD42020199099.

Analgesic effects of dexmedetomidine and remifentanil on periprocedural pain during percutaneous ablation of renal carcinoma

Background: Percutaneous ablation of renal carcinoma is frequently a favourable treatment alternative, especially in elderly patients suffering from co-morbidities. Also, it is less resource-demanding than conventional surgery of renal carcinoma, and one may, therefore, assume that the incidence of this procedure may increase. Analgesia is necessary during this intervention. The aim of this study was to explore the possibility of analgosedation and its relation to patient comfort and safety during percutaneous ablation of renal carcinoma.Methods: Forty-six patients, sedated with dexmedetomidine and remifentanil, supplemented with infiltration anaesthesia (lidocaine 1%), underwent percutaneous (radiofrequency or microwave) ablation of renal carcinoma in this prospective study.Results: The patients expected pain intensity around the numerical rating score (NRS) 4.5 (interquartile range [IQR] 3.5-5.5), which was slightly lower than pain experienced during the procedure NRS 5 (IQR 2-7; p = 0.49). Eight percent of the patients needed supplementary morphine during the ablation procedure. Sedation score did not differ during ablation, at arrival to or discharge from the recovery ward. Median periprocedural treatment time was 12 minutes (IQR 12-16). Treatment time did not correlate with experienced pain (R²=0.000074, p = 0.96). The median length of stay in the recovery room was 120 minutes (IQR 84-154). There were seven serious adverse events.Conclusions: This proof-of-concept study has shown that analgosedation during percutaneous ablation of renal carcinoma can be performed with a generally tolerable degree of patient satisfaction. However, pain occurs and should be managed adequately. Patient safety must be a major concern for the anaesthetic care.

Long-Term Survival after Percutaneous Radiofrequency Ablation of Pathologically Proven Renal Cell Carcinoma in 100 Patients

PURPOSE

To determine the long-term survival of patients treated with percutaneous radiofrequency (RF) ablation for pathologically proven renal cell carcinoma (RCC).

MATERIALS AND METHODS

In this single-center retrospective study, 100 patients with 125 RCCs (100 clear-cell, 19 papillary, and 6 chromophobe) 0.8-8 cm in size treated with RF ablation were evaluated at a single large tertiary-care center between 2004 and 2015. Technical success, primary and secondary technique efficacy, and pre- and postprocedural estimated glomerular filtration rate (eGFR) at 3-6 months and 2-3 years were recorded. Overall survival, cancer-specific survival, and local tumor progression-free survival were calculated by Kaplan-Meier survival curves. Complications were classified per the Clavien-Dindo system. Statistical testing was done via χ² tests for proportions and paired t test for changes in eGFR. Statistical significance was set at α = 0.05.

RESULTS

Overall technical success rate was 100%, and primary and secondary technique efficacy rates were 90% and 100%, respectively. Median follow-up was 62.8 months, ranging from 1 to 120 months. The 10-year overall, cancer-specific, and local progression-free survival rates were 32%, 86%, and 92%, respectively. The number of ablation probes used was predictive of residual unablated tumor (P < .001). There were no significant changes in preprocedure vs 2-3-years postprocedure eGFR (65.2 vs 62.1 mL/min/1.73 m²; P = .443). There was a 9% overall incidence of complications, the majority of which were grade I.

CONCLUSIONS

Image-guided percutaneous RF ablation of RCCs is effective at achieving local control and preventing cancer-specific death within 10 years from initial treatment.

Deep learning and radiomics: the utility of Google TensorFlow™ Inception in classifying clear cell renal cell carcinoma and oncocytoma on multiphasic CT

PURPOSE

Currently, all solid enhancing renal masses without microscopic fat are considered malignant until proven otherwise and there is substantial overlap in the imaging findings of benign and malignant renal masses, particularly between clear cell RCC (ccRCC) and benign oncocytoma (ONC). Radiomics has attracted increased attention for its utility in pre-operative work-up on routine clinical images. Radiomics based approaches have converted medical images into mineable data and identified prognostic imaging signatures that machine learning algorithms can use to construct predictive models by learning the decision boundaries of the underlying data distribution. The TensorFlow™ framework from Google is a state-of-the-art open-source software library that can be used for training deep learning neural networks for performing machine learning tasks. The purpose of this study was to investigate the diagnostic value and feasibility of a deep learning-based renal lesion classifier using open-source Google TensorFlow™ Inception in differentiating ccRCC from ONC on routine four-phase MDCT in patients with pathologically confirmed renal masses.

METHODS

With institutional review board approval for this 1996 Health Insurance Portability and Accountability Act compliant retrospective study and a waiver of informed consent, we queried our institution's pathology, clinical, and radiology databases for histologically proven cases of ccRCC and ONC obtained between January 2000 and January 2016 scanned with a an intravenous contrast-enhanced four-phase renal mass protocol (unenhanced (UN), corticomedullary (CM), nephrographic (NP), and excretory (EX) phases). To extract features to be used for the machine learning model, the entire renal mass was contoured in the axial plane in each of the four phases, resulting in a 3D volume of interest (VOI) representative of the entire renal mass. We investigated thirteen different approaches to convert the acquired VOI data into a set of images that adequately represented each tumor which was used to train the final layer of the neural network model. Training was performed over 4000 iterations. In each iteration, 90% of the data were designated as training data and the remaining 10% served as validation data and a leave-one-out cross-validation scheme was implemented. Accuracy, sensitivity, specificity, positive (PPV) and negative predictive (NPV) values, and CIs were calculated for the classification of the thirteen processing modes.

RESULTS

We analyzed 179 consecutive patients with 179 lesions (128 ccRCC and 51 ONC). The ccRCC cohort had a mean size of 3.8 cm (range 0.8-14.6 cm) and the ONC cohort had a mean lesion size of 3.9 cm (range 1.0-13.1 cm). The highest specificity and PPV (52.9% and 80.3%, respectively) were achieved in the EX phase when we analyzed the single mid-slice of the tumor in the axial, coronal and sagittal plane, and when we increased the number of mid-slices of the tumor to three, with an accuracy of 75.4%, which also increased the sensitivity to 88.3% and the PPV to 79.6%. Using the entire tumor volume also showed that classification performance was best in the EX phase with an accuracy of 74.4%, a sensitivity of 85.8% and a PPV of 80.1%. When the entire tumor volume, plus mid-slices from all phases and all planes presented as tiled images, were submitted to the final layer of the neural network we achieved a PPV of 82.5%.

CONCLUSIONS

The best classification result was obtained in the EX phase among the thirteen classification methods tested. Our proof of concept study is the first step towards understanding the utility of machine learning in the differentiation of ccRCC from ONC on routine CT images. We hope this could lead to future investigation into the development of a multivariate machine learning model which may augment our ability to accurately predict renal lesion histology on imaging.

The uremic toxin p-cresyl sulfate induces proliferation and migration of clear cell renal cell carcinoma via microRNA-21/ HIF-1α axis signals

p-Cresyl sulfate (pCS), a uremic toxin, can cause renal damage and dysfunction. Studies suggest that renal dysfunction increases the prevalence of renal cancer. However, the effect of pCS on the proliferation and migration of renal cancer is unclear. Clear cell renal cell carcinoma (ccRCC) expresses mutant von Hippel-Lindau gene and is difficult to treat. Hypoxia-inducible factor-1α and 2-α (HIF-1α and HIF-2α) as well as microRNA-21 (miR-21) can regulate the proliferation and migration of ccRCC cells. However, the association between HIF-α and miR-21 in ccRCC remains unclear. Therefore, the effects of pCS on ccRCC cells were investigated for HIF-α and miR-21 signals. Our results showed that pCS induced overexpression of HIF-1α and promoted the proliferation and regulated epithelial-mesenchymal transition-related proteins, including E-cadherin, fibronectin, twist and vimentin in ccRCC cells. pCS treatment increased miR-21 expression. Specifically, inhibition of miR-21 blocked pCS-induced proliferation and migration. Taken together, the present results demonstrate that pCS directly induced the proliferation and migration of ccRCC cells through mechanisms involving miR-21/HIF-1α signaling pathways.

Transarterial embolization of renal cell carcinoma as an adjunctive therapy prior to cryoablation: a propensity score matching analysis

PURPOSE

We aimed to assess the safety and effectiveness of transarterial embolization (TAE) prior to percutaneous cryoablation (PCA) in the management of renal cell carcinoma (RCC) compared with PCA alone using a propensity score matching analysis to minimize confounding factors.

METHODS

A retrospective review of all PCAs performed for renal masses identified 9 patients who underwent TAE prior to PCA. These patients were matched in a 2:1 ratio with patients who underwent PCA only using age, gender, and tumor size to create the propensity score model for matching. Other demographic, clinical, and outcomes data were collected.

RESULTS

The TAE+PCA group included 5 males and 4 females with a mean age of 67.9 years and mean tumor diameter of 51.7 mm. The PCA only group included 11 males and 7 females with a mean age of 66.8 years and mean tumor diameter of 46.2 mm. No significant differences in these propensity score matched characteristics were identified. Further, the groups had no significant differences in tumor geometry (P = 0.831), R.E.N.A.L. nephrometry scores (P = 0.144), or comorbidity indices (P = 0.392). TAE was technically successful and without complication in all cases. PCA was technically successful in 8 of 9 patients in the TAE+PCA group and in 14 of 18 patients in the PCA only group (P = 0.483). No significant differences in the rate of complications (P = 0.483), change in eGFR (P = 0.691), or change in hematocrit (P = 0.152) were identified between the two groups.

CONCLUSION

TAE of RCC prior to PCA is safe and technically feasible; however, no objective benefits over PCA alone were identified by propensity score matching analysis. Due to small sample size and limitations of the study, no definite conclusions should be drawn. Larger, prospective studies of this therapeutic approach are warranted.

Organ-sparing procedures in GU cancer: part 1-organ-sparing procedures in renal and adrenal tumors: a systematic review

PURPOSE

Organ-sparing surgery (OSS) for the kidney and adrenals has emerged as the need for preservation of function is paramount in patients with poor functional reserve. As reports increasingly showed that oncological outcomes were equivalent to radical excision, elective OSS became a viable alternative in patients with otherwise normal reserve. In this review, we summarize the current knowledge of OSS for adrenal and renal tumors.

MATERIALS AND METHODS

PubMed, Web of Science and Cochrane Library Central Search were searched for recently published articles up to December 2017. The following keywords were used; "partial adrenalectomy", "adrenal sparing", "partial nephrectomy", "nephron sparing", "kidney/renal cancer".

RESULTS

Partial adrenalectomy became an attractive alternative to total adrenalectomy avoiding adrenal insufficiency. Both minimally invasive surgery and ablative techniques were increasingly reported for adrenal OSS with adequate residual adrenal function and excellent oncological outcome. Radical nephrectomy remained for many years as the gold standard of treatment for organ-confined renal cell carcinoma. As the need to reduce the impact on renal function, more conservative approaches were utilized. Soon, the non-inferiority of nephron-sparing surgery to that of radical excision became evident and elective partial nephrectomy was gaining ground as the standard of care for small renal masses in patients with normal contralateral kidneys.

CONCLUSIONS

Herein, we present a comprehensive review of the current status of OSS in renal and adrenal tumors.

Partial nephrectomy versus ablative techniques for small renal masses: a systematic review and network meta-analysis

PURPOSE

To compare partial nephrectomy (PN), radiofrequency ablation (RFA), cryoablation (CRA) and microwave ablation (MWA) regarding oncologic, perioperative and functional outcomes.

MATERIAL AND METHODS

The MEDLINE, EMBASE and COCHRANE libraries were searched for studies comparing PN, RFA, CRA or MWA and reporting on any-cause or cancer-specific mortality, local recurrence, complications or renal function. Network meta-analyses were performed.

RESULTS

Forty-seven studies with 24,077 patients were included. Patients receiving RFA, CRA or MWA were older and had more comorbidities compared with PN. All-cause mortality was higher for CRA and RFA compared with PN (incidence rate ratio IRR = 2.58, IRR = 2.58, p < 0.001, respectively). No significant differences in cancer-specific mortality were evident. Local recurrence was higher for CRA, RFA and MWA compared with PN (IRR = 4.13, IRR = 1.79, IRR = 2.52, p < 0.05 respectively). A decline in renal function was less pronounced after RFA versus PN, CRA and MWA (mean difference in GFR MD = 6.49; MD = 5.82; MD = 10.89, p < 0.05 respectively).

CONCLUSION

Higher overall survival and local control of PN compared with ablative therapies did not translate into significantly better cancer-specific mortality. Most studies carried a high risk of bias by selecting younger and healthier patients for PN, which may drive superior survival and local control. Physicians should be aware of the lack of high-quality evidence and the potential benefits of ablative techniques for certain patients, including a superior complication profile and renal function preservation.

KEY POINTS

• Patients selected for ablation of small renal masses are older and have more comorbidities compared with those undergoing partial nephrectomy. • Partial nephrectomy yields lower all-cause mortality, which is probably biased by patient selection and does not translate into prolonged cancer-free survival. • The decline of renal function is smallest after radiofrequency ablation for small renal masses.

Trans-Arterial Embolization of Renal Cell Carcinoma prior to Percutaneous Ablation: Technical Aspects, Institutional Experience, and Brief Review of the Literature

This report describes the technical aspects of trans-arterial embolization (TAE) of renal cell carcinoma prior to percutaneous ablation. All patients (n = 11) had a single renal mass (mean tumor diameter = 50.2 mm; range: 28-84 mm). Selective TAE was performed via the common femoral artery. Embolic materials included: particles alone (n = 4), coils alone (n = 1), particles + ethiodized oil (n = 2), particles + coils (n = 1), ethiodized oil + ethanol (n = 2), and particles + ethanol (n = 1). All embolizations were technically successful and no complications have been reported. After embolization, 10 patients underwent cryoablation while 1 patient underwent microwave ablation. Ablations were technically successful in 10 of the 11 patients. Only 3 minor complications were identified but none required treatment. No adverse effect on the patient's glomerular filtration rate was seen from the additional procedure (p = 0.84). TAE of renal cell carcinoma prior to percutaneous ablation is safe and technically-feasible.

Localized chromophobe renal cell carcinoma: preoperative imaging judgment and laparoscopic simple enucleation for treatment

Objective:

To evaluate the preoperative imaging manifestation and therapeutic effect of laparoscopic simple enucleation (SE) for localized chromophobe renal cell carcinoma (chRCC).

Materials and Methods:

Clinical data of 36 patients who underwent laparoscopic SE of localized chRCC at our institute were retrospectively analyzed. All patients underwent preoperative renal protocol CT (unenhanced, arterial, venous, and delayed images). CT scan characteristics were evaluated. After intraoperative occlusion of the renal artery, the tumor was free bluntly along the pseudocapsule and enucleated totally. The patients were followed up regularly after the operation.

Results:

Mean tumor diameter was 3.9±1.0 cm, 80% of tumors were homogeneous and all the tumors had complete pseudocapsule. The attenuation values were slightly lower than normal renal cortex and degree of enhancement of the tumors were significantly lower than normal renal cortex. Mean operation time was 104.3±18.2 min. Mean warm ischemia time (WIT) was 21.3±3.5 min. Mean blood loss was 78.6±25.4 mL. No positive surgical margin was identified. Mean postoperative hospital stay was 5.3±1.5 d. Hematuria occurred in 3 patients and all disappeared within 3 days. After a mean follow-up of 32.1±20.6 months, no patient had local recurrence or metastatic progression.

Conclusion:

Localized chRCCs have a great propensity for homogeneity and complete pseudocapsule. The attenuation values were slightly lower than normal renal cortex and small degree of enhancement. Laparoscopic SE is a safe and effective treatment for localized chRCC. The oncological results were satisfactory.

Partial versus radical nephrectomy for T1b-2N0M0 renal tumors: A propensity score matching study based on the SEER database

Purpose

Controversy continues on the tailored therapy for patients with larger renal cell carcinoma (RCC). We investigated whether partial nephrectomy (PN) can improve patient prognosis compared to radical nephrectomy (RN) and the indications for each approach in patients with T1b-2N0M0 RCC.

Materials and methods

A total of 9907 patients were identified from the Surveillance, Epidemiology, and End Results database from 2004 to 2012. Propensity scores were used to balance the selection bias of undergoing PN. Overall (OS) and cancer-specific survival (CSS) of patients undergoing PN and RN were compared. Cases were subdivided to investigate the advantages of each procedure.

Results

Overall, 1418 (14.3%) patients underwent PN. Before matching, PN led to better OS and CSS than RN in both Kaplan-Meier analysis and Cox regression (each p<0.01). For 1412 matched cohorts, PN was no longer associated with significantly better OS (HR: 1.19, 95% CI: 0.98–1.44), but still with a better CSS (HR: 1.66, 95% CI: 1.18–2.27) compared with RN. Further subgroup analysis indicated that patients, who were male, single living, old than 65 years, with T1b stage or clear-cell histologic type, may obtained more oncologic benefit from PN compared to RN.

Conclusions

When tumor localization and technical feasibility have been taken into account, similar long-term survival was achieved in overall among two nephrectomy modalities, but patients, who were male, old than 65 years, with T1b stage or clear-cell histologic type, got a better survival after receiving PN compared to RN.