Routine small renal mass needle biopsy should be adopted

Adverse Histopathologic Characteristics in Small Papillary Renal Cell Carcinomas Have Minimal Impact on Prognosis

OBJECTIVES

Tumor size has long been used in the management decision-making of patients with renal masses. Active surveillance had recently gained traction in selected patients with tumor size of 4 cm or less. Adverse histopathologic characteristics in papillary renal cell carcinoma (PRCC) have been shown to correlate with worse prognosis. We aimed to study whether such features in small PRCCs provide additional prognostic information.

METHODS

Nephrectomies from our institution were collected and reviewed to evaluate for adverse histopathologic features. Clinical follow-up information was collected for all cases. Relationships between the variables were examined by Wilcoxon test and logistic regression.

RESULTS

We identified 291 consecutive cases of PRCC. Adverse tumor histopathologic characteristics were significantly related to size. In PRCCs with size greater than 4 cm, there were more cases with high World Health Organization/International Society of Urological Pathology grade and necrosis. Adverse histologic features are less commonly seen in small PRCC and are not associated with lower disease-free survival or disease-specific survival.

CONCLUSIONS

Identification of these features in small PRCCs (≤4 cm) through needle core biopsy examination would not provide additional prognostic information in patients for whom active surveillance is considered. Clinical and radiologic follow-up in patients with small renal masses that have a known histologic diagnosis of PRCC should be sufficient.

Renal mass biopsy: A strategy to reduce associated costs and morbidity when managing localized renal masses

INTRODUCTION AND OBJECTIVES

Renal mass biopsy (RMB) has not been widely adopted in evaluating small renal mass due to concerns for safety, efficacy, and its perceived lack of consequence on management decisions. We assess the potential cost savings and morbidity avoidance of routine RMB on cT1 renal masses undergoing robotic-assisted partial nephrectomy (RAPN).

METHODS

We identified n = 920 consecutive RAPN pT1 renal masses and n = 429 consecutive RMBs for cT1 renal masses over 12 years. Using a novel pathological-based risk classification system for cT1 renal masses, we evaluated the morbidity and costs of our RAPN and RMB cohorts. We then define four clinical scenarios where RMB could potentially delay and/or avoid intervention in our pT1 RAPN cohort and model potential complications prevented and cost savings utilizing common clinical scenarios.

RESULTS

Using our risk stratification system in RAPN patients, final histology was classified as benign in n=174 (18.9%) cases, very low-risk (n = 62 [7%]), low-risk (n = 383 [42%]), and high-risk (n = 301 [33%]), respectively. We identified n = 116 (12.6%) Clavien graded peri-operative complications. In our RMB patients, 120 (27.9%), 17 (3.9%), 240 (55.9%), 52(12.1%) were benign, very low, low and high-risk tumors. The median total direct cost for RAPN was $6955/case compared to $1312/case for RMB. If we established a primary goal to avoid immediate extirpative surgery in benign renal tumors, in the elderly (>70 y) with very low-risk tumors and/or those with high renal functional risks (≥ CKD3b), or competing risks (ASA ≥ 3), RMB could have reduced direct costs by approximately 20% and avoided n = 39 Clavien graded complications, seven readmissions, three transfusions, and two returns to the OR. With the additional cost of performing RMB on those not initially biopsied, the net cost saving would be approximately $1.2 million with minimal added complications while still treating high-risk tumors.

CONCLUSIONS

Routine RMB before intervention results in cost-saving and complication avoidance. Given the limitations of biopsy, shared decision-making is mandatory. Biopsy should be considered prior to intervention in at-risk populations.

Active Surveillance in Small Renal Masses in the Elderly: A Literature Review

CONTEXT

Small renal masses have become increasingly common due to widespread imaging; however, optimal management of these lesions in the elderly can be complex due to the competing risks of intervention, natural history of disease, patient comorbidities, and expectations. In the properly selected elderly patient, active surveillance remains an accepted and attractive treatment approach.

OBJECTIVE

We completed a literature review of small renal masses (enhancing, <4cm, T1aN0M0 disease) in the elderly, aged ≥70 yr, aimed at identifying the utility of active surveillance in this population. The primary outcomes were conversion to active treatment while on active surveillance and cancer-specific mortality. Secondary outcomes included predictors of treatment, type of treatment performed (partial nephrectomy, radical nephrectomy, and ablation), progression to metastases, all-cause mortality, tumor growth rate, and demographic data including age and Charlson Comorbidity Index.

EVIDENCE ACQUISITION

A comprehensive search of electronic databases (e.g., MEDLINE, EMBASE, SCOPUS, Web of Science, and the Cochrane Library) using search terms "small renal mass" OR "SRM", AND "elderly," "senior," "aging," "geriatric," OR "octogenarian" was completed. All randomized controlled trials, nonrandomized comparison studies, and case series were included and screened by the reviewers. All comparison studies included in the systematic review were assessed for methodological quality using the Cochrane Risk of Bias tools.

EVIDENCE SYNTHESIS

Seventeen primary studies including 36495 patients met the inclusion criteria for the systematic review. All studies were retrospective institutional chart or the Surveillance, Epidemiology, and End Results database reviews. There was a low (4-26%) rate of conversion to active treatment for active surveillance in the identified studies over a follow-up interval of up to 91.5 mo. Overall mortality was substantial in this elderly cohort, with 15-51% of patients being deceased over the course of study follow-up; however, there was minimal cancer-specific mortality due to patients succumbing to alternative comorbid disease. In the future, patient comorbidity and biological age versus the natural history of the individualized tumor biology may play an increasing role in the discussion regarding treatment options and consideration of active surveillance.

CONCLUSIONS

Active surveillance is an effective management strategy in the elderly population. Few patients required the conversion to active treatment and there was low cancer-specific mortality. The majority of patients who expired over the course of the identified studies succumbed to alternative disease. The goal of treatment strategies should include weighing patient-specific prognosis relative to their competing health risks and treatment goals against the natural history of disease and risks of intervention.

PATIENT SUMMARY

In this review article, the authors examined the utility of active surveillance in the setting of a small localized renal mass in the elderly population. Despite being on surveillance, we found that cancer-specific outcomes were excellent, and overall mortality was often a result of comorbid disease. However, there is significant heterogeneity among elderly patients, and treatment approaches should be focused around patient-centered goals and prognosis.

Aorta-Lesion-Attenuation-Difference (ALAD) on contrast-enhanced CT: a potential imaging biomarker for differentiating malignant from benign oncocytic neoplasms

OBJECTIVE

To evaluate whether the Aorta-Lesion-Attenuation-Difference on contrast-enhanced CT can aid in the differentiation of malignant and benign oncocytic renal neoplasms.

MATERIALS AND METHODS

Two independent cohorts-an initial (biopsy) dataset and a validation (surgical) dataset-with oncocytomas and chromophobe renal cell carcinomas (chRCC) were included in this IRB-approved retrospective study. A region of interest was placed on the renal mass and abdominal aorta on the same CT image slice to calculate an Aorta-Lesion-Attenuation-Difference (ALAD). ROC curves were plotted for different enhancement phases, and diagnostic performance of ALAD for differentiating chRCC from oncocytomas was calculated.

RESULTS

Seventy-nine renal masses (56 oncocytomas, 23 chRCC) were analyzed in the initial (biopsy) dataset. Thirty-six renal masses (16 oncocytomas, 20 chRCC) were reviewed in the validation (surgical) cohort. ALAD showed a statistically significant difference between oncocytomas and chromophobes during the nephrographic phase (p < 0.001), early excretory phase (p < 0.001), and excretory phase (p = 0.029). The area under the ROC curve for the nephrographic phase was 1.00 (95% CI: 1.00-1.00) for the biopsy dataset and showed the narrowest confidence interval. At a threshold value of 25.5 HU, sensitivity was 100 (82.2%-100%) and specificity was 81.5 (61.9%-93.7%). When tested on the validation dataset on measurements made by an independent reader, the AUROC was 0.93 (95% CI: 0.84-1.00) with a sensitivity of 100 (80.0%-100%) and a specificity of 87.5 (60.4%-97.8%).

CONCLUSIONS

Nephrographic phase ALAD has potential to differentiate benign and malignant oncocytic renal neoplasms on contrast-enhanced CT if histologic evaluation on biopsy is indeterminate.

Active Surveillance for Renal Neoplasms with Oncocytic Features is Safe

PURPOSE

Oncocytomas are benign tumors often diagnosed incidentally on imaging. Small case series have suggested that the growth kinetics of oncocytomas are similar to those of malignant renal tumors. Biopsy material may be insufficient to exclude a diagnosis of chromophobe renal cell carcinoma. We evaluated and compared the growth rates of oncocytoma and chromophobe renal cell carcinoma to improve our understanding of their natural history.

MATERIALS AND METHODS

This was a single center, retrospective study of patients diagnosed with lesions suggestive of oncocytoma or chromophobe renal cell carcinoma between 2003 and 2014. The growth rates were estimated using a mixed effect linear model. Patient and lesion characteristics were tested using a similar model for association with growth rate.

RESULTS

Of the 95 lesions (oncocytoma 81, chromophobe renal cell carcinoma 14) included in the analysis 98% were diagnosed on biopsy. The annual growth rate was 0.14 cm and 0.38 cm for oncocytoma (median followup 34 months) and chromophobe renal cell carcinoma (median followup 25 months), respectively (p=0.5). Baseline lesion size was significantly associated with growth (p <0.001). The majority of oncocytomas (74%) and chromophobe renal cell carcinomas (67%) followed up to the 3-year mark had grown. Of these, 8 underwent surgery (6 in the chromophobe renal cell carcinoma group). The initial diagnosis was confirmed in all. Overall 5 patients died, all of nonrenal related causes.

CONCLUSIONS

Although the majority of oncocytic renal neoplasms will grow with time, surveillance appears to remain safe. Patients opting for this strategy should be made aware that a diagnosis of oncocytoma following biopsy is associated with some degree of uncertainty due to the difficulty of differentiating them from other oncocytic renal neoplasms.

Indications for biopsy and the current status of focal therapy for renal tumours

The increased detection of small renal masses (SRMs) has focused attention on their uncertain natural history. The development of treatment alternatives and the discovery of biologically targeted drugs have also raised interest. Renal mass biopsies (RMBs) have a crucial role as they provide the pathological, molecular and genetic information needed to classify these lesions and guide clinical management. The improved accuracy has improved our knowledge of the behaviour of different tumour histologies and opened the potential for risk-adapted individualized treatment approaches. To date, studies have demonstrated that percutaneous ablation is an effective therapy with acceptable outcomes and low risk in the appropriate clinical setting. Although partial nephrectomy (PN) is still considered the standard treatment for SRM, percutaneous ablation is increasingly being performed and if long-term efficacy is sustained, it may have a wider application for SRMs after biopsy characterization.