Editing CUA: Small Renal Masses (2015)



'''See Original Guideline'''

===== Background =====

* '''Definition of small renal mass (SRM):'''

#* '''Enhancing tumours'''
#* '''<4 cm in diameter'''
#* '''with image characteristics consistent with stage T1aN0M0 renal cell carcinoma'''

* Most SRMs are RCCs, ≈20-25% of SRMs are benign
* Even if SRMs are malignant, most of them grow slowly
* '''Small RCCs may be associated with metastatic disease at diagnosis in up to 8% of cases, so initial staging of all SRM patients is essential'''

#* '''Recall 2014 CUA Surgical Management of Renal Cell Carcinoma Consensus Statementrecommended investigations'''
#** '''History and physical'''
#** '''Labs: CBC, Cr, LFTs, calcium'''
#** '''Imaging: cross-sectional of primary tumour, CXR/CT'''

* Based on current data, initial active surveillance (AS) with delayed treatment for local progression appears to be a relatively safe initial management strategy

===== '''Role of needle core biopsy of SRMs''' =====

* Biopsy appears safe and at least 80% of first biopsies are diagnostic. Repeat biopsy may be considered.
* Multiple tumours may have different histology and tumour grade, so multiple and repeat biopsies may be required to accurately characterize tumour histology.
* '''Biopsy for histologic characterization should be reserved for patients in whom the results might change management'''
* '''However, biopsy is not yet a standard of care in Canada'''

===== '''Management of SRMs''' =====

* '''Options:'''
** '''Partial nephrectomy (recommended)'''
** '''Laparoscopic radical nephrectomy'''
*** '''Reserved for tumours not amenable to partial nephrectomy'''
** '''Thermal ablation (RFA or cryotherapy)'''
*** '''A biopsy should be obtained before or at the time of ablation'''
*** Morbidity is low; can be performed on an outpatient basis without general anesthesia in a cost-effective manner
*** Attractive approach in elderly and comorbid patients
*** '''Long-term follow-up with imaging is required''' and local recurrence occurs in up to 14% of patients.
*** Success rates decrease in tumours >3 cm in diameter
** '''Active surveillance'''
*** '''Low rates of progression, including a low rate of metastasis of 1-2%'''
**** '''Likely underestimate as studies have limited follow-up and most SRMs''' are not biopsy proven to be cancer
*** Long-term follow-up is required to establish the safety of this approach in the young and fit patient.
*** Prognostic factors for progression are poorly understood, but primary tumour growth rate is the most widely used trigger for delayed treatment
*** '''Active surveillance with regular radiographic follow-up should be a primary consideration for SRMs in elderly and/ or infirm patients with multiple comorbidities that would make them high risk for intervention, and in those with limited life expectancy'''
*** '''Suggested follow-up:''' computed tomography (CT) or magnetic resonance imaging every 3 months in the first year, every 6 months in the next 2 years and every year thereafter. US may be reasonable to substitute for CT/MRI