SUO 2017: Small Renal Masses and New Guidelines in Management

Washington, DC ( Dr. Ithaar Derweesh from UC San Diego provided a comprehensive review of the new 2017 AUA Guidelines for small renal masses [1] at the 18th Annual Meeting of the Society of Urologic Oncology. The focus of this guideline was clinically localized renal masses suspicious for cancer in adults, including solid enhancing renal tumors and Bosniak 3 and 4 complex cystic renal masses. A main departure from the 2009 guidelines was that there were no index patients, considering there is great variance in patient/oncologic/functional characteristics, the panel recommends individualized counseling/management. 

New additions to the 2017 guidelines include: (i) increased emphasis on functional aspects, recognizing their importance for survivorship, (ii) role of renal mass biopsy, (iii) primary role for partial nephrectomy for T1a renal masses and otherwise, (iv) restricted role for radical nephrectomy with well-defined selection criteria, (v) shared decision making for active surveillance, and (vi) selective utilization of thermal ablation (<3 cm in size). 

Statements 1-3 for evaluation and diagnosis include specific recommendations about imaging, laboratory evaluation, metastatic workup, and staging of chronic kidney disease (CKD). Statements 4-9 regarding counseling include (i) a urologist leading the counseling process and a multidisciplinary team being included when necessary, (ii) addressing oncologic/functional issues and potential comorbidities, and (iii) specific recommendations for genetic counseling or referral to nephrology 

Statements 10-13 regarding utilization of renal mass biopsy include consideration when a mass is suspected to be hematologic, metastatic, inflammatory, or infectious – beyond these considerations renal mass biopsy should be obtained on a utility-based approach. Renal mass biopsy is not required for young or healthy patients who are unwilling to accept uncertainties associated with biopsy, and older or frail patients who will be managed conservatively independent of biopsy findings. When considering renal mass biopsy, patients should be counseled regarding rationale, positive and negative predictive values and potential risks. Indeed, renal mass biopsy is safe, with low rates of hematoma (4.9%), pain (1.2%), gross hematuria (1.0%), pneumothorax (0.6%), or hemorrhage requiring transfusion (0.4%). Furthermore, a positive biopsy has a sensitivity of 98%, specificity of 96% and PPV of 99.8%. Non-diagnostic rates of 14% can be substantially reduced by repeating renal mass biopsy and histologic evaluation of RCC subtype is also very accurate. 

Statements 14-18 addresses partial nephrectomy noting that physicians should prioritize partial nephrectomy for management of cT1 renal masses when intervention is indicated, minimizing the risk of CKD. Not only are there equivalent oncologic outcomes to radical nephrectomy, complications of partial nephrectomy can generally be managed with conservative measures. Indications for partial nephrectomy include young patients who have longer life expectancy who are at increased risk of recurrent or contralateral disease, and competing health risks that are may impact future renal function. The exact threshold for warm ischemia at which irreversible damage begins to occur is somewhat debatable but generally accepted to be 25-30 minutes. Indications for enucleation include familial RCC, multi-focal disease, and severe CKD. 

Statement 19 addresses selection criteria for radical nephrectomy. In the setting of increased oncologic risk, radical nephrectomy is preferred if all of the following criteria are met: (i) high tumor complexity and partial nephrectomy would be challenging, (ii) no pre-existing proteinuria or chronic kidney disease, (iii) normal contralateral kidney and baseline post-operative eGFR likely to be >45 ml/min/1.73m2

Statements 20-23 discussed surgical principles, noting that (i) for patients with clinically concerning regional lymphadenopathy, surgeons should perform a lymphadenectomy for staging purposes, (ii) surgeons should perform an adrenalectomy if imaging and/or intraoperative findings suggest metastasis or direct invasion of the adrenal gland, (iii) a minimally invasive approach should be considered when not compromising oncologic outcomes, (iv) pathologic evaluation of the adjacent renal parenchyma should be performed for partial or radical nephrectomy to assess for determinants of chronic kidney disease or risk factors for subsequent CKD. 

Secondary to a subsequent talk in this session addressing thermal ablation, Dr. Derweesh did not address these statements in his talk. Statements 28-31 discussed active surveillance of small renal masses, noting that short term (12-36 months) cancer specific survival of active surveillance exceeds 95% in select patients (mostly <2 cm). This is considered an acceptable option for patients considered to be low oncologic risk, and those whose life expectancy is unacceptable for surgical risk. When the decision is made to undergo active surveillance, diligent follow-up at 3-6 month intervals is recommended. Patients should be counseled that the risk of metastases is low (<3%), but the risk does exist. 


1. Campbell S, Uzzo RG, Allaf ME, et al. Renal Mass and Localized Renal Cancer: AUA Guideline. Available at:

Presented by: Ithaar H. Derweesh, MD, UC San Diego Health, San Diego, CA 

Written by: Zachary Klaassen, MD, Society of Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre @zklaassen_md at the 18th Annual Meeting of the Society of Urologic Oncology, November 20-December 1, 2017 – Washington, DC