Comparison of renal function detriments after local tumor ablation or partial nephrectomy for renal cell carcinoma

Ablation of Kidney Tumors in Patients with Substantial Kidney Impairment: Current Status

PURPOSE OF REVIEW

To review the current status of kidney tumor ablation in patients with substantial kidney impairment.

RECENT FINDINGS

Few reports of kidney tumor ablation in such patients have recently been published. The reported prevalence of patients with stage 4 or 5 chronic kidney disease (CKD) among patients undergoing ablation is 2.0%-10%. In patients with stage 4 or 5 CKD, local tumor control rates were 88%-100%. The effect of ablation on CKD stage is unclear, and the observed deteriorations in kidney function are consistent with both the effect of cryoablation and the natural course of advanced CKD. According to guidelines, active surveillance may be selected. The goals of treatment are complete tumor removal and maintenance of kidney function, both of which can be met by ablation. Given the limited treatment options, ablation may play a pivotal role in the management of patients with advanced CKD.

Percutaneous Ablation vs Robot-Assisted Partial Nephrectomy for Completely Endophytic Renal Masses: A Multicenter Trifecta Analysis with a Minimum 3-Year Follow-Up

Purpose: To compare outcomes of robot-assisted partial nephrectomy (RAPN) and percutaneous tumor ablation (PTA) for completely endophytic renal masses. Methods: Data of patients who underwent RAPN or PTA for treatment of completely endophytic (three points for "E" domain of R.E.N.A.L. score) were collected from seven high-volume U.S. and European centers. PTA included cryoablation, radiofrequency, or microwave ablation. Baseline characteristics, clinical, surgical, and postoperative outcomes were compared. Recurrence-free survival (RFS) was calculated with Kaplan-Meier analysis. Trifecta was used as arbitrary combined outcome parameter as proxy for treatment "quality." Multivariable logistic regression model assessed predictors of trifecta failure. Results: One hundred fifty-two patients (RAPN, n = 60; PTA, n = 92) were included in the analysis. RAPN group was younger (p < 0.001), had lower American Society of Anesthesiologists score (p = 0.002), and higher baseline estimated glomerular filtration rate (p < 0.001). There was no difference in clinical tumor size, clinical T stage, and tumor complexity scores. PTA had significantly lower rate of overall (p < 0.001) and minor (p < 0.001) complications. ΔeGFR at 1 year was statistically higher for RAPN (-15.5 mL/min vs -3.1 mL/min; p = 0.005), no difference in ΔeGFR at last follow-up (p = 0.22) was observed. No difference in recurrences (RAPN, n = 2; PTA, n = 6) and RFS was found (p = 0.154). Trifecta achievement was higher for RAPN but not statistically different (65.3% vs 58.8%; p = 0.477). R.E.N.A.L. Nephrometry Score resulted predictive of trifecta failure (odds ratio = 1.47; confidence interval = 1.13-1.90; p = 0.004). Conclusions: PTA confirms to be an effective treatment for completely endophytic renal masses, offering low complications and good mid-term functional and oncologic outcomes. These outcomes compare favorably with those of RAPN, which seem to be the preferred option for younger and less comorbid patients.

Percutaneous ablation of renal tumors versus surgical ablation and partial nephrectomy: Medicare trends and reimbursement cost comparison from 2010 to 2018

PURPOSE

The purpose of this study is to analyze trends in Medicare volume and reimbursement for percutaneous and surgical ablation as well as laparoscopic and open partial nephrectomy for treatment of small renal tumors from 2010 to 2018.

METHODS

Claims from the Medicare Part B Physician/Supplier Procedure Summary from 2010 to 2018 were extracted using CPT codes for percutaneous and surgical renal ablation and surgical and laparoscopic partial nephrectomy. Facility reimbursement and relative value units (RVUs) were obtained using the Centers for Medicare & Medicaid Services physician fee schedule look-up tool.

RESULTS

Volume of percutaneous ablation increased from 2539 to 4571 procedures (80.0%). Specifically, percutaneous cryoablation became the dominant technique, increasing from 1434 to 2981 procedures (107.9%). Overall, volume of partial nephrectomy also increased by 40.4%, driven by an increase in laparoscopic partial nephrectomy from 3227 to 7770 procedures (140.8%) with a decrease in open partial nephrectomy from 3489 to 1661 (- 52.4%). Volume of surgical ablations also decreased 72.7% from 1260 to 344 procedures. In 2018, reimbursement was $358.56 for percutaneous radiofrequency ablation, $481.32 for percutaneous cryoablation, $1216.43 for surgical radiofrequency ablation, $1269.35 for surgical cryoablation, $1381.67 for open partial nephrectomy, and $1552.66 for laparoscopic partial nephrectomy.

CONCLUSION

There has been a trend toward minimally invasive techniques for treatment of small renal tumors among Medicare patients. Laparoscopic partial nephrectomy has become the dominant treatment. In the setting of evidence showing comparable outcomes with surgery as well as lower costs to insurers, the volume of percutaneous ablation has also markedly increased.

Risk Factors for Renal Function Impairment Following Radiofrequency Ablation of Renal Tumors

Purpose

Materials and Methods

Results

Conclusion

Functional and oncologic outcomes of robot-assisted simple enucleation with and without renal arterial cold perfusion in complex renal tumors: a propensity score-matched analysis

BACKGROUND

To compare robot-assisted simple enucleation with renal arterial cold perfusion (RACP-RASE) and RASE alone in complex renal tumors with regard to perioperative, functional and oncologic outcomes by propensity score-matched analysis.

METHODS

Data from 351 patients who underwent RACP-RASE or RASE for complex renal tumors were recorded between September 2014 and December 2017. Propensity score-matched analysis was performed on age, sex, BMI, ECOG score, tumor side and size, preoperative estimated glomerular filtration rate (eGFR), RENAL score and PADUA score.

RESULTS

The study included 31 RACP-RASE and 320 RASE procedures. RENAL score and PADUA score were higher and tumor diameter was greater under RACP-RASE than RASE. After matching, the two groups were similar in estimated blood loss (208.3 vs 230.7 ml; p = 0.696) and ischemic time (34.8 vs 32.8 min; p = 0.342). The RACP-RASE group had significantly longer operative time than the RASE group (264.1 ± 55.7 vs 206.9 ± 64.0 min, p = 0.001). There was no difference in the incidence of postoperative complications between the two groups (13.8% vs 24.1%; p = 0.315), as was the overall incidence of positive surgical margins (3.4 vs 0%; p = 1.000). The changes in eGFR significantly differed between the two groups at 3 months (p = 0.018) and 12 months (p = 0.038). More patients in the RASE group were CKD upstaged (p = 0.043). At multivariable analysis, preoperative eGFR and the type of procedure were significant predictive factors for a change of more than 10% in eGFR at 3 months postoperatively. There was no local recurrence or distant metastasis during follow-up.

CONCLUSIONS

RACP-RASE is an effective and safe technique for complex renal tumors that can provide appropriate temporary arterial occlusion and renal hypothermic perfusion. Renal arterial cold perfusion may be helpful in protecting renal function in RASE as compared with warm ischemia.

Percutaneous Microwave Ablation of Category T1a Renal Cell Carcinoma: Intermediate Results on Safety, Technical Feasibility, and Clinical Outcomes of 119 Tumors

OBJECTIVE. The purpose of this study was to assess the safety, technical results, and clinical outcomes of CT-guided percutaneous microwave ablation of category T1a renal cell carcinoma. MATERIALS AND METHODS. This retrospective study investigated consecutive patients who underwent CT-guided microwave ablation for T1a renal cell carcinoma from October 2015 to May 2019. Patient demographics including tumor characteristics, comorbidities, technical details, and clinical outcomes were evaluated. Local progression-free survival and overall survival rates were estimated using the Kaplan-Meier method. RESULTS. One hundred-six patients including 70 men (mean age, 68.5 ± 8.9 [SD] years; range, 49-86 years) and 36 women (mean age, 69.5 ± 10.0 years; range, 50-88 years) with an overall mean age of 68.8 ± 9.2 years (range, 49-88 years) with 119 T1a renal cell carcinomas were treated with CT-guided microwave ablation. Technical success was achieved for 100% of the tumors. Complete response was achieved in 101 (95.3%) patients and partial response was achieved in five (4.7%) patients. Local progression-free survival was 100.0%, 92.8%, and 90.6% at 1, 2, and 3 years, respectively. Overall survival was 99.0%, 97.7%, and 94.6% at 1, 2, and 3 years, respectively. Six patients (5.7%) had seven complications (five with Clavien-Dindo Grade I, Society of Interventional Radiology [SIR] category A, two with Clavien-Dindo Grade III, SIR category B) within 30 days of the procedure. CONCLUSION. CT-guided percutaneous microwave ablation is associated with high rates of technical success, excellent local progression-free survival and overall survival, and a low complication rate for category T1a renal cell carcinoma.

Local ablation vs partial nephrectomy in T1N0M0 renal cell carcinoma: An inverse probability of treatment weighting analysis

Objective

To compare the survival outcomes of local ablation (LA) and partial nephrectomy (PN) for T1N0M0 renal cell carcinoma (RCC).

Method

We identified 38,155 T1N0M0 RCC patients treated with PN or LA in 2004‐2016 from the retrospective Surveillance, Epidemiology, and End Results databases. Among them, there were 4656 LA and 33,499 PN. A Cox proportional hazards regression model, cause‐specific Cox regression and Fine and Gray sub‐distribution hazard ratio (sHR) with inverse probability of treatment weighting (IPTW) adjusting was utilized to compare the effects of LA vs PN on all‐, RCC‐, and non‐RCC–caused mortality.

Results

Within the IPTW analysis, patients who underwent PN experienced a better overall survival (OS) (HR, 1.56; 95% CI, 1.40‐1.74; P < .001) and cancer‐specific survival (CSS) (HR, 2.21; 95% CI, 1.62‐2.98; P < .001) than LA patients. In the subgroup of patients >85 years (HR, 1.14; 95% CI, 0.73‐1.79, P = .577), chromophobe RCC (HR, 1.68; 95% CI, 0.94‐3.00, P = .078), and tumor size <2 cm (HR, 1.21; 95% CI, 0.95‐1.53, P = .126), the OS showed no significant difference between LA and PN. No significant difference in CSS between LA and PN was observed in the subgroup of chromophobe RCC (HR, 0.34; 95% CI, 0.03‐3.97, P = .389), and tumor size <2 cm (HR, 1.83; 95% CI, 0.92‐3.64, P = .084). For patients >85 years (sHR, 0.89; 95% CI, 0.52‐1.27, P = .520) and tumor size <2 cm (sHR, 1.14; 95% CI, 0.94‐1.38, P = .200), the non‐RCC–specific mortality was not significantly different in PN and LA cohorts, however, for the chromophobe RCC, the LA showed a worse non‐RCC mortality than PN (HR, 1.72; 95% CI, 1.06‐2.79, P = .028).

Conclusion

PN showed a better prognosis than LA in T1N0M0 RCC treatment, but LA and PN showed a comparable OS in elderly patients (>85), small RCC (<2 cm) and chromophobe RCC.

Early trends and predictors of renal function following computed tomography-guided percutaneous cryoablation of a renal mass in patients with and without prior renal impairment

OBJECTIVE

To assess trends and predictors of the glomerular filtration rate (GFR) after renal mass cryoablation in patients with and without history of renal impairment.

MATERIALS AND METHODS

This was a retrospective study of 39 patients who underwent computed tomography-guided percutaneous cryoablation of a renal mass, divided into two groups: those with prior renal impairment (PRI+); and those without prior renal impairment (PRI-). The GFR trend and the chronic kidney disease stage were evaluated at baseline, as well as at 1, 6, and 12 months after cryoablation. Predictors of GFR at 1 and 6 months were modeled with linear regression.

RESULTS

In both groups, the mean GFR at 1 month and 6 months was significantly lower than at baseline (p < 0.001 and p = 0.01, respectively). Although the GFR was lower across all time points in the PRI+ group (-26.1; p < 0.001), the overall trend was not statistically different from that observed in the PRI- group (p = 0.89). Univariate analysis showed that the decline in GFR at 1 and 6 months correlated with the baseline GFR (0.77 and 0.63; p < 0.001 and p = 0.03, respectively) and with the size of the ablation zone (-7.6 and -12.84, respectively; p = 0.03 for both). However, in the multivariate model, baseline GFR was predictive only of GFR at 1 month (p < 0.001).

CONCLUSION

The trend in GFR decline after cryoablation is similar for patients with and without a history of renal impairment. Baseline GFR predicts the mean GFR in the early post-cryoablation period.

Thermal Ablation of T1a Renal Cell Carcinoma: The Clinical Evidence

Renal cell carcinoma (RCC) is most commonly diagnosed at an early (T1a) stage and is typically amenable to several effective treatments. The current gold standard therapy is partial nephrectomy, given its decreased morbidity and similar oncologic outcomes when compared with radical nephrectomy. Thermal ablation is an evolving definitive therapy for T1a RCC which is even less invasive than partial nephrectomy. This article reviews the evidence for thermal ablation in the treatment of T1a RCC and compares outcomes of existing ablation modalities with surgical management.

Treatment Trends and Long-Term Survival Associated with Cryotherapy and Partial Nephrectomy for Small Renal Masses in the National Cancer Database Using Propensity Score Matching

Objective: Trends in the utilization of ablative therapy are unknown for the treatment of small renal masses. Our goal is to utilize the National Cancer Database (NCDB) to both assess the utilization of ablative therapies and long-term survival. Materials and Methods: The NCDB captures 70% of all cancer cases in the United States and was queried between 1998 and 2012 for renal cell carcinomas that were treated with ablative therapy, partial nephrectomy (PN), or radical nephrectomy. The analysis was limited to clinical stage T_1a. Propensity score matching was used in 1:1 fashion. Kaplan-Meier survival analysis and a Cox proportional hazards model were used to compare overall survival (OS) for cryotherapy and PN. Results: A total of 119,240 cases of clinical stage T_1a renal masses were treated between 1998 and 2012. Cryotherapy peaked at 927 (9.1%) cases in 2010 and had 913 (8.4%) in 2012. PN accounted for 18% of the cases in 1998, but surpassed the utilization of nephrectomy in 2008. By 2012, PN accounted for 6766 (62%) of renal mass cases. After matching, Kaplan-Meier OS was lower for cryotherapy compared with PN at 24 (94.5% vs 96.5%), 48 (86.8% vs 90.9%), and 96 months (66.0% vs 74.9%). Cryotherapy also had a lower OS (hazard ratio 1.46; p < 0.001) on adjusted analysis. Conclusion: Cryotherapy for small renal masses plateaued at 9% utilization in 2009. Cryotherapy had a lower OS than PN for tumors >2 cm on adjusted analysis, but this result should be used with caution until confirmed in randomized studies.

Can ablation win against partial nephrectomy and become first line therapy in cT1a renal tumours?

PURPOSE OF REVIEW

Currently, small renal masses account for the largest proportion of renal tumour and small renal cell carcinomas (RCC). Although partial nephrectomy, whenever possible, is recognized as the gold standard for treatment, thermal ablation has gained increasing attention as optional treatment in a population sector harbouring small renal masses/small RCCs. The purpose of this review is to update comparative outcomes between these two options of treatment.

RECENT FINDINGS

Recent observational case-control and population-based cohorts applying propensity score or inverse probability treatment weighted methodology adjusting for baseline patient and tumour characteristics, compare outcomes between partial nephrectomy and thermal ablation (both cryotherapy and radiofrequency), radical nephrectomy and thermal ablation and between thermal ablation and nonsurgical management. Most of them focus on T1aRCC.

SUMMARY

Comparative outcomes' evidence is limited to population-based or institutional series adjusted for baseline differences and systematic reviews. With exception of special clinical situations, thermal ablation provides similar estimated 5-year cancer and overall survival with a clear benefit in postoperative outcomes when compared to partial nephrectomy in cT1a older patients. The trade-off is more evident when thermal ablation is compared to radical nephrectomy. The advantages in terms of adverse events persist up to 1 year after treatment. Benefits are less apparent in solitary kidneys and when synchronous bilateral approaches are performed.

Outcome Measures Used to Report Kidney Function in Studies Investigating Surgical Management of Kidney Tumours: A Systematic Review

CONTEXT

Most practice decisions relevant to preserving kidney function in patients managed surgically for kidney tumours are driven by observational studies. A wide range of outcome measures are used in these studies, which reduces comparability and increases the risk of reporting bias.

OBJECTIVE

To comprehensively and succinctly describe the outcomes used to evaluate kidney function in studies evaluating surgical management of kidney tumours.

EVIDENCE ACQUISITION

Electronic search of the PubMed database was conducted to identify studies with at least one measure of kidney function in patients managed surgically for kidney tumours, published between January 2000 and September 2017. Abstracts were initially screened for eligibility. Full texts of articles were then evaluated in more detail for inclusion. A narrative synthesis of the evidence was conducted.

EVIDENCE SYNTHESIS

A total of 312 studies, involving 127905 participants, were included in this review. Most were retrospective (n=274) studies and conducted in a single centre (n=264). Overall, 78 unique outcome measures were identified, which were grouped into six outcome categories. Absolute postoperative kidney function (n=187), relative kidney function (n=181), and postoperative chronic kidney disease (n=131) were most frequently reported. Kidney function was predominantly quantified using estimated glomerular filtration rate or creatinine clearance (n=255), most using the modification of diet in renal disease equation (n=182). Only 70 studies provided rationale for specific outcome measures used.

CONCLUSIONS

There is significant variability in the reporting and quantification of kidney function in studies evaluating patients managed surgically for kidney tumours. A standardised approach to measuring and reporting kidney function will increase the effectiveness of outcomes reported and improve relevance of research findings within a clinical context.

PATIENT SUMMARY

Although we know that the removal of a kidney can reduce kidney function, clinical significance of various approaches is a matter of debate. This article demonstrates significant variability in the way kidney function was reported across all studies of patients with kidney cancer undergoing surgery, indicating a need for standardisation.

Comparative effectiveness in urology: a state of the art review utilizing a systematic approach

PURPOSE OF REVIEW

Comparative effectiveness research plays a vital role in healthcare delivery by guiding evidence-based practices. We performed a state-of-the-art review of comparative effectiveness research in the urology literature for 2016, utilizing a systematic approach. Seven high-impact papers are reviewed in detail.

RECENT FINDINGS

Across the breadth of urology, there were several important studies in comparative effectiveness research, of which we will highlight two randomized controlled trials and five observational trials: radiotherapy, prostatectomy, and active monitoring have equivalent mortality outcomes in patients with localized prostate cancer; the ideal modality of patient education is yet to be determined, and written education has minimal effect on patient perception of prostate specific antigen screening; robotic prostatectomy is associated with higher perioperative complication rates on a population basis; racial disparities exist in incontinence rates after treatment for localized prostate cancer, but not in irritative, bowel, or sexual function; androgen deprivation therapy is associated with higher fracture, peripheral artery disease, and cardiac-related complications than bilateral orchiectomy; robotic and open cystectomy offer comparable cancer-specific mortality and perioperative outcomes; and bonuses for low-cost hospitals can inadvertently reward low-quality hospitals.

SUMMARY

There have been major advancements in comparative effectiveness research in urology in 2016.

Focal ablation therapy for renal cancer in the era of active surveillance and minimally invasive partial nephrectomy

Partial nephrectomy is the optimal surgical approach in the management of small renal masses (SRMs). Focal ablation therapy has an established role in the modern management of SRMs, especially in elderly patients and those with comorbidities. Percutaneous ablation avoids general anaesthesia and laparoscopic ablation can avoid excessive dissection; hence, these techniques can be suitable for patients who are not ideal surgical candidates. Several ablation modalities exist, of which radiofrequency ablation and cryoablation are most widely applied and for which safety and oncological efficacy approach equivalency to partial nephrectomy. Data supporting efficacy and safety of ablation techniques continue to mature, but they originate in institutional case series that are confounded by cohort heterogeneity, selection bias, and lack of long-term follow-up periods. Image guidance and surveillance protocols after ablation vary and no consensus has been established. The importance of SRM biopsy, its optimal timing, the type of biopsy used, and its role in treatment selection continue to be debated. As safety data for active surveillance and experience with minimally invasive partial nephrectomy are expanding, the role of focal ablation therapy in the treatment of patients with SRMs requires continued evaluation.

Renal functional outcomes in patients undergoing percutaneous cryoablation or partial nephrectomy for a solitary renal mass

OBJECTIVES

To compare renal functional changes after percutaneous cryoablation (PCA) or partial nephrectomy (PN).

PATIENTS AND METHODS

Patients who underwent PCA or PN for a solitary renal mass at a single institution were identified (2003-2013). Estimated glomerular filtration rates (eGFRs) were calculated at baseline, discharge, and at the 3-month follow-up using the Chronic Kidney Disease Epidemiology Collaboration equation. Changes in renal function were compared between groups using 1:1 propensity score (PS) matching, adjustment for PS quintile, and inverse probability weighting (IPW).

RESULTS

There were 2 040 procedures available for the PS analyses, including 448 PCA and 1 592 PN. After PS adjustments, there were no significant differences in baseline clinical features between PCA and PN patients. In the PS-matched analysis, the change in eGFR from baseline to discharge for PCA and PN patients was -3.1 and -1.1 mL/min/1.73 m² , respectively (P = 0.038), with percentage changes of -4.5% and 0% respectively (P = 0.006). From baseline to the 3-month follow-up, the absolute change in eGFR for PCA and PN patients was -4.3 and -2.1 mL/min/1.73 m² , respectively (P = 0.008), and the percentage change was -6.1% and -2.4% respectively (P = 0.005). Similar results were obtained after adjusting for PS quintiles and in the IPW analysis. Importantly, the rate of chronic kidney disease stage progression at the 3-month follow-up was similar between the groups (21% vs 18%).

CONCLUSIONS

Our results confirm that both PCA and PN have a minor impact on renal function. While we observed a statistically greater decline in eGFR after PCA compared with PN, both approaches result in excellent preservation of renal function.

Effect of Tumor Complexity and Technique on Efficacy and Complications after Percutaneous Microwave Ablation of Stage T1a Renal Cell Carcinoma: A Single-Center, Retrospective Study

Purpose To evaluate the effects of tumor complexity and technique on early and midterm oncologic efficacy and rate of complications for 100 consecutive biopsy-proved stage T1a renal cell carcinomas (RCCs) treated with percutaneous microwave ablation. Materials and Methods This HIPAA-compliant, single-center retrospective study was approved by the institutional review board. The requirement to obtain informed consent was waived. Ninety-six consecutive patients (68 men, 28 women; mean age, 66 years ± 9.4) with 100 stage T1a N0M0 biopsy-proved RCCs (median diameter, 2.6 cm ± 0.8) underwent percutaneous microwave ablation between March 2011 and June 2015. Patient and procedural data were collected, including body mass index, comorbidities, tumor histologic characteristics and grade, RENAL nephrometry score, number of antennas, generator power, and duration of ablation. Technical success, local tumor progression, and presence of complications were assessed at immediate and follow-up imaging. The Kaplan-Meier method was used for survival analyses. Results Technical success was achieved for all 100 tumors (100%), including 47 moderately and five highly complex RCCs. Median clinical and imaging follow-up was 17 months (range, 0-48 months) and 15 months (range, 0-44 months), respectively. No change in estimated glomerular filtration rate was noted after the procedure (P = .49). There were three (3%) procedure-related complications and six (6%) delayed complications, all urinomas. One case of local tumor progression (1%) was identified 25 months after the procedure. Three-year local progression-free survival, cancer-specific survival, and overall survival were 88% (95% confidence interval: 0.52%, 0.97%), 100% (95% confidence interval: 1.0%, 1.0%), and 91% (95% confidence interval: 0.51%, 0.99%), respectively. Conclusion Percutaneous microwave ablation is an effective and safe treatment option for stage T1a RCC, regardless of tumor complexity. Long-term follow-up is needed to establish durable oncologic efficacy and survival relative to competing ablation modalities and surgery. ^© RSNA, 2017.

Population-based assessment of cancer-specific mortality after local tumour ablation or observation for kidney cancer: a competing risks analysis

OBJECTIVES

To examine, using competing risks regression, differences in cancer-specific mortality (CSM) that might distinguish between local tumour ablation (LTA) and observation (OBS) for patients with kidney cancer.

PATIENTS AND METHODS

The study focused on 1 860 patients with cT1a kidney cancer treated with either LTA or OBS between 2000 and 2009 in the Surveillance Epidemiology and End Results-Medicare database. Propensity-score matching was used. The study outcome was CSM. Multivariable competing risks regression analyses, adjusting for other-cause mortality as well as patient (including comorbidities) and tumour characteristics, were fitted.

RESULTS

Overall, fewer patients underwent LTA than OBS (30 vs 70%; n = 553 vs n = 1 307). Compared with patients in the OBS group, those in the LTA group were younger (median age 77 vs 78 years; P < 0.001), more likely to be white (84 vs 78%; P = 0.005), more frequently married (59 vs 52%; P = 0.02) and more frequently of high socio-economic status (54 vs 45%; P = 0.001). After propensity-score matching, 553 patients who underwent LTA and 553 who underwent OBS remained for subsequent analyses. The mean standardized differences of patient characteristics between the two groups were <10%, indicating a high degree of similarity. After LTA or OBS, the 5-year CSM estimates from Poisson regression-derived smoothed plots were 3.5 and 9.1%, respectively. In multivariable competing risks regression analyses, LTA use was found to have a protective effect on CSM (hazard ratio 0.47 [95% confidence interval 0.25-0.89]; P = 0.02).

CONCLUSIONS

After adjustment for comorbidity and tumour characteristics in elderly patients with kidney cancer, LTA was associated with a clinically and statistically significant protective effect on CSM, compared with OBS. This advantage of LTA deserves consideration when obtaining informed consent.

The Past, Present, and Future in Management of Small Renal Masses

Management of small renal masses (SRMs) is currently evolving due to the increased incidence given the ubiquity of cross-sectional imaging. Diagnosing a mass in the early stages theoretically allows for high rates of cure but simultaneously risks overtreatment. New consensus guidelines and treatment modalities are changing frequently. The multitude of information currently available shall be summarized in this review. This summary will detail the historic surgical treatment of renal cell carcinoma with current innovations, the feasibility and utility of biopsy, the efficacy of ablative techniques, active surveillance, and use of biomarkers. We evaluate how technology may be used in approaching the small renal mass in order to decrease morbidity, while keeping rates of overtreatment to a minimum.