CUA GUIDELINE: SMALL RENAL MASS 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
- 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
