Evaluation, Management, and Follow Up of Renal Mass and Localized Renal Cancer: AUA Guideline

Renal masses are a biologically heterogeneous group of tumors ranging from benign masses to cancers that can be indolent or aggressive.7,8 The true incidence of renal masses (including benign masses) is unknown. However, benign masses comprise approximately 15-20 percent of surgically resected tumors < 4 cm and allow estimations of benign incidence based on kidney cancer statistics.7,9,10 The vast majority (greater than 90%) of kidney cancers in the United States are renal cortical tumors known as RCC.

American Urological Association (AUA) has released guidelines titled Renal Mass and Localized Renal Cancer: Evaluation, Management, and Follow Up on (2021). This AUA Guidelines focuses on the evaluation and management of clinically localized sporadic renal masses suspicious for renal cell carcinoma (RCC) in adults, including solid enhancing renal tumors and Bosniak 3 and 4 complex cystic renal masses. Some patients with clinically localized renal masses may present with findings suggesting aggressive tumor biology or may be upstaged on exploration or final pathology.

Following are its major recommendations:

1. In patients with a solid or complex cystic renal mass, clinicians should obtain high quality, multiphase, cross-sectional abdominal imaging to optimally characterize and clinically stage the renal mass. Characterization of the renal mass should include assessment of tumor complexity, degree of contrast enhancement (where applicable), and presence or absence of fat. (Clinical Principle)

2. In patients with suspected renal malignancy, clinicians should obtain a comprehensive metabolic panel, complete blood count, and urinalysis. Metastatic evaluation should include chest imaging to evaluate for possible thoracic metastases. (Clinical Principle)

3. patients with a solid or Bosniak 3/4 complex cystic renal mass, clinicians should assign chronic kidney disease (CKD) stage based on glomerular filtration rate (GFR) and degree of proteinuria. (Expert Opinion)

4. In patients with a solid or Bosniak 3/4 complex cystic renal mass, a urologist should lead the counseling process and should consider all management strategies. A multidisciplinary team should be included when necessary. (Expert Opinion)

5. Clinicians should provide counseling that includes current perspectives about tumor biology and a patient-specific risk assessment inclusive of sex, tumor size/complexity, histology (when obtained), and imaging characteristics. For cT1a tumors, the low oncologic risk of many small renal masses should be reviewed. (Clinical Principle)

6. During counseling of patients with a solid or Bosniak 3/4 complex cystic renal mass, clinicians must review the most common and serious urologic and non-urologic morbidities of each treatment pathway and the importance of patient age, comorbidities/frailty, and life expectancy. (Clinical Principle)

7. Clinicians should review the importance of renal functional recovery related to renal mass management, including the risks of progressive CKD, potential short- or long-term need for renal replacement therapy, and long-term overall survival considerations. (Clinical Principle)

8. Clinicians should consider referral to nephrology in patients with a high risk of CKD progression, including those with estimated glomerular filtration rate (eGFR) less than 45 mL/min/1.73m2, confirmed proteinuria, diabetics with preexisting CKD, or whenever eGFR is expected to be less than 30 mL/min/1.73m2 after intervention. (Expert Opinion)

9. Clinicians should recommend genetic counseling for any of the following: all patients ≤ 46 years of age with renal malignancy, those with multifocal or bilateral renal masses, or whenever 1) the personal or family history suggests a familial renal neoplastic syndrome; 2) there is a first-or second-degree relative with a history of renal malignancy or a known clinical or genetic diagnosis of a familial renal neoplastic syndrome (even if kidney cancer has not been observed); or 3) the patient's pathology demonstrates histologic findings suggestive of such a syndrome. (Expert Opinion)

10. When considering the utility of RMB, patients should be counseled regarding rationale, positive and negative predictive values, potential risks and non-diagnostic rates of RMB. (Moderate Recommendation; Evidence Level: Grade C)

11. Clinicians should consider RMB when a mass is suspected to be hematologic, metastatic, inflammatory, or infectious. (Clinical Principle)

12. In the setting of a solid renal mass, RMB should be obtained on a utility-based approach whenever it may influence management. RMB is not required for 1) young or healthy patients who are unwilling to accept the uncertainties associated with RMB; or 2) older or frail patients who will be managed conservatively independent of RMB findings. (Expert Opinion)

13. For patients with a solid renal mass who elect RMB, multiple core biopsies should be performed and are preferred over fine needle aspiration (FNA). (Moderate Recommendation; Evidence Level: Grade C)

14. Clinicians should prioritize PN for the management of the cT1a renal mass when intervention is indicated. In this setting, PN minimizes the risk of CKD or CKD progression and is associated with favorable oncologic outcomes, including excellent local control. (Moderate Recommendation; Evidence Level: Grade B)

15. Clinicians should prioritize nephron-sparing approaches for patients with solid or Bosniak 3/4 complex cystic renal masses and an anatomic or functionally solitary kidney, bilateral tumors, known familial RCC, preexisting CKD, or proteinuria. (Moderate Recommendation; Evidence Level: Grade C)

16. Nephron-sparing approaches should be considered for patients with solid or Bosniak 3/4 complex cystic renal masses who are young, have multifocal masses, or comorbidities that are likely to impact renal function in the future, including but not limited to moderate to severe hypertension, diabetes mellitus, recurrent urolithiasis, or morbid obesity. (Moderate Recommendation; Evidence Level: Grade C)

17. In patients who elect PN, clinicians should prioritize preservation of renal function by optimizing nephron mass preservation and avoiding prolonged warm ischemia. (Expert Opinion)

18. For patients undergoing PN, clinicians should prioritize negative surgical margins. The extent of normal parenchyma removed should be determined by surgeon discretion taking into account the clinical situation and tumor characteristics, including growth pattern, and interface with normal tissue. Tumor enucleation should be considered in patients with familial RCC, multifocal disease, or severe CKD to optimize parenchymal mass preservation. (Expert Opinion)

19. Clinicians should consider RN for patients with a solid or Bosniak 3/4 complex cystic renal mass whenever increased oncologic potential is suggested by tumor size, RMB (if obtained), and/or imaging. (Moderate Recommendation; Evidence Level: Grade B) In this setting, RN is preferred if all of the following criteria are met: 1) high tumor complexity and PN would be challenging even in experienced hands; 2) no preexisting CKD or proteinuria; and 3) normal contralateral kidney and new baseline eGFR will likely be greater than 45 mL/min/1.73m2 even if RN is performed. If all of these criteria are not met, PN should be considered unless there are overriding concerns about the safety or oncologic efficacy of PN. (Expert Opinion)

20. For patients who are undergoing surgical excision of a renal mass with clinically concerning regional lymphadenopathy, clinicians should perform a lymph node dissection including all clinically positive nodes for staging purposes. (Expert Opinion)

21. For patients who are undergoing surgical excision of a renal mass, clinicians should perform adrenalectomy if imaging and/or intraoperative findings suggest metastasis or direct invasion of the adrenal gland. (Clinical Principle)

22. In patients undergoing surgical excision of a renal mass, a minimally invasive approach should be considered when it would not compromise oncologic, functional, and perioperative outcomes. (Expert Opinion)

23. Pathologic evaluation of the adjacent renal parenchyma should be performed and recorded after PN or RN to assess for possible intrinsic renal disease, particularly for patients with CKD or risk factors for developing CKD. (Clinical Principle)

24. Clinicians should consider referral to medical oncology whenever there is concern for potential clinical metastasis or incompletely resected disease (macroscopic positive margin or gross residual disease). Patients with high-risk or locally advanced, fully resected renal cancers should be counselled about the risks/benefits of adjuvant therapy and encouraged to participate in adjuvant clinical trials, facilitated by medical oncology consultation when needed. (Clinical Principle)

25. Clinicians should consider TA as an alternate approach for the management of cT1a solid renal masses <3 cm in size. For patients who elect TA, a percutaneous technique is preferred over a surgical approach whenever feasible to minimize morbidity. (Moderate Recommendation; Evidence Level: Grade C)

26. Both radiofrequency ablation (RFA) and cryoablation may be offered as options for patients who elect TA. (Conditional Recommendation; Evidence Level: Grade C)

27. A RMB should be performed prior to (preferred) or at the time of ablation to provide pathologic diagnosis and guide subsequent surveillance. (Expert Opinion)

28. Counseling about TA should include information regarding an increased likelihood of tumor persistence or local recurrence after primary TA relative to surgical excision, which may be addressed with repeat ablation if further intervention is elected. (Strong Recommendation; Evidence Level: Grade B)

29. For patients with a solid renal mass <2cm, or those that are complex but predominantly cystic, clinicians may elect AS with potential for delayed intervention for initial management. (Conditional Recommendation; Evidence Level: Grade C)

30. For patients with a solid or Bosniak 3/4 complex cystic renal mass, clinicians should prioritize AS/expectant management when the anticipated risk of intervention or competing risks of death outweigh the potential oncologic benefits of active treatment. In asymptomatic patients, the panel recommends periodic clinical surveillance and/or imaging based on shared decision making. (Clinical Principle)

31. For patients with a solid or Bosniak 3/4 complex cystic renal mass in whom the risk/benefit analysis for treatment is equivocal and who prefer AS, clinicians should consider RMB (if the mass is solid or has solid components) for further oncologic risk stratification. Repeat cross-sectional imaging should be obtained approximately 3-6 months later to assess for interval growth. Periodic clinical/imaging surveillance can then be based on growth rate and shared decision-making with intervention recommended if substantial interval growth is observed or if other clinical/imaging findings suggest that the risk/benefit analysis is no longer equivocal or favorable for continued AS. (Expert Opinion)

32. For patients with a solid or Bosniak 3/4 complex cystic renal mass in whom the anticipated oncologic benefits of intervention outweigh the risks of treatment and competing risks of death, clinicians should recommend intervention. AS with potential for delayed intervention may be pursued only if the patient understands and is willing to accept the associated oncologic risks. In this setting, clinicians should encourage RMB (if the mass is predominantly solid) for additional risk stratification. If the patient continues to prefer AS, close clinical and cross-sectional imaging surveillance with periodic reassessment and counseling should be recommended. (Moderate Recommendation; Evidence Level: Grade C)

33. Clinicians coordinating follow-up for patients who have undergone intervention for a renal mass should discuss the implications of stage, grade, and histology including the risks of recurrence and possible sequelae of treatment. Patients with pathologically-proven benign renal masses should undergo occasional clinical evaluation and laboratory testing for sequelae of treatment but most do not require routine periodic imaging. (Expert Opinion)

34. Patients with treated malignant renal masses should undergo periodic medical history, physical examination, laboratory studies, and imaging directed at detecting signs and symptoms of metastatic spread and/or local recurrence as well as evaluation for possible sequelae of treatment. (Clinical Principle)

35. Patients with treated malignant renal masses should have periodic laboratory testing including serum creatinine, eGFR, and urinalysis. Other laboratory evaluations (e.g., complete blood count, lactate dehydrogenase, liver function tests, alkaline phosphatase and calcium level) may be obtained at the discretion of the clinician or if advanced disease is suspected. (Expert Opinion)

36. Patients undergoing follow-up for treated renal masses with progressive renal insufficiency or proteinuria should be referred to nephrology. (Expert Opinion)

37. Patients undergoing follow-up for treated malignant renal masses should only undergo bone scan if one or more of the following is present: clinical symptoms such as bone pain, elevated alkaline phosphatase, or radiographic findings suggestive of a bony neoplasm. (Moderate Recommendation; Evidence Level: Grade C)

38. Patients undergoing follow-up for treated malignant renal masses with acute neurological signs or symptoms should undergo prompt magnetic resonance imaging (MRI) or computed tomography (CT) scanning of the brain and/or spine. (Strong Recommendation; Evidence Level: Grade A)

39. For patients undergoing follow-up for treated malignant renal masses, additional site-specific imaging can be ordered as warranted by clinical symptoms suggestive of recurrence or metastatic spread. Positron emission tomography (PET) scan should not be obtained routinely but may be considered selectively. (Moderate Recommendation; Evidence Level: Grade C)

40. Patients with findings suggestive of metastatic renal malignancy should be evaluated to define the extent of disease and referred to medical oncology. Surgical resection or ablative therapies should be considered in select patients with isolated or oligo-metastatic disease. (Expert Opinion)

41. Patients with findings suggesting a new renal primary or local recurrence of renal malignancy should undergo metastatic evaluation including chest and abdominal imaging. If the new primary or recurrence is isolated to the ipsilateral kidney and/or retroperitoneum, a urologist should be involved in the decision-making process, and surgical resection or ablative therapies may be considered. (Expert Opinion)

42. Patients managed with surgery (PN or RN) for a renal malignancy should undergo abdominal imaging according to Table 1, with CT or MRI pre- and post-intravenous contrast preferred. (Moderate Recommendation; Evidence Strength: Grade C). After 2 years, abdominal ultrasound (US) alternating with cross-sectional imaging may be considered in the LR and IR groups at physician discretion. After 5 years, informed/shared decision-making should dictate further abdominal imaging. (Expert Opinion)

43. Patients managed with surgery (PN or RN) for a renal malignancy should undergo chest imaging (chest x-ray [CXR] for LR and IR; CT chest preferred for HR and VHR) according to Table 1. (Moderate Recommendation; Evidence Strength: Grade C). After 5 years, informed/shared decision-making discussion should dictate further chest imaging and CXR may be utilized instead of chest CT for HR and VHR (Expert Opinion)

44. Patients undergoing ablative procedures with biopsy that confirmed malignancy or was non-diagnostic should undergo pre- and post-contrast cross-sectional abdominal imaging within 6 months (if not contraindicated). Subsequent follow-up should be according to the recommendations for the IR postoperative protocol (Table 1). (Expert Opinion)

Note:

AUA categorizes body of evidence strength as Grade A (well-conducted and highly-generalizable RCTs or exceptionally strong observational studies with consistent findings), Grade B (RCTs with some weaknesses of procedure or generalizability or moderately strong observational studies with consistent findings), or Grade C (RCTs with serious deficiencies of procedure or generalizability or extremely small sample sizes or observational studies that are inconsistent, have small sample sizes, or have other problems that potentially confound interpretation of data). Where gaps in the evidence existed, the Panel provides guidance in the form of Clinical Principles or Expert Opinion with consensus achieved using a modified Delphi technique if differences of opinion emerged.

Reference:

Campell SC, Clark PE, Chang SS et al: Renal Mass and Localized Renal Cancer: Evaluation, Management, and Follow-Up: AUA Guideline Part I. J Urol 2021; 206: 199. Campbell SC, Uzzo RG, Karam JA, et al: Renal Mass and Localized Renal Cancer: Evaluation, Management, and Follow-up: AUA Guideline: Part II. J Urol 2021; 206: 209.