Table 1. Summary of recommendations from 7 worldwide regional urological organisations with published guidelines.
| International body | Guideline year | Definition | Recommendations for role of renal mass biopsy | Recommendations regarding management/AS | Protocol for follow-up for AS patients |
|---|---|---|---|---|---|
| European Association of Urology (1) | 2020 | cT1a | Before ablation treatment. In select patients who are considering AS | Offer active surveillance, radiofrequency ablation or cryoablation to frail and/or comorbid patients with small renal masses. Treat Bosniak III cysts the same as RCC or offer AS. Treat Bosniak IV cysts the same as RCC | Not mentioned |
| American Urological Association (8) | 2017 | ‘small solid’ ‘Bosniak III or IV complex cysts’ | For lesions suspected to be non-malignant. Before thermal ablation. Not required for (I) young or healthy patients who are unwilling to accept the uncertainties associated with RMB; or (II) older or frail patients who will be managed conservatively independent of RMB findings | AS can be considered for suspicious renal masses, especially those smaller than 2 cm. Prioritise AS or watchful waiting when risk of intervention or competing risk of death outweigh oncological benefit of active treatment | Repeat imaging 3–6 months to assess for interval growth. Use cross sectional imaging and/or US. May consider RMB for additional risk stratification. Trigger for treatment: tumour size >3 cm, growth rate >5 mm/year, stage progression, clinical change in patient/tumour factors |
| European Society for Medical Oncology (9) | 2019 | <4 cm solid tumour | Recommended for select patients with small masses for AS | AS is an option in elderly patients with significant comorbidities or those with short life expectancy. Otherwise PN is recommended for T1 <7 cm tumours | Not mentioned |
| Canadian Urological Association (Kidney Cancer Research Network of Canada) (10) | 2015 | cT1a ‘<4cm’ | Perform if changes management. Perform before, or at the time of, ablation for SRM. Is not yet standard practice in Canada |
Active surveillance with radiographic follow up should be primary consideration in elderly and infirm patients at high risk of intervention and limited life expectancy | CT 3-monthly in year 1, 6-montly in year 2–3, yearly thereafter |
| Can use ultrasound +/- contrast enhancement | |||||
| Japanese Urological Association (11) | 2011, 2007 | cT1a | Not mentioned | Partial nephrectomy or nephrectomy | N/A |
| Ablation or cryotherapy is an option | |||||
| Latin American Renal Cancer group (14) | 2019 | ‘small renal mass’ not otherwise defined | Recommend biopsy when patients are candidates for AS | PN should be applied in most patients with an SRM. AS used an alternative for suspicious masses, particularly those smaller than 3 cm. AS preferred when risks of intervention or the competing risks of death outweigh benefit to patient. AS preferential for: elderly, life expectancy <5 years, frailty, multiple comorbidities, marginal renal function, tumour growth of <5 mm/year, or well differentiated histology | CT or MRI or US every 3–6 months for 2 years to establish an acceptable linear growth rate (<0.5 cm per year). Subsequently, annual imaging every 6–12 months |
| Sociedad Argentina de Urología (12) | 2010 | Renal mass less than 2 cm | For lesions suspected to be non-malignant | Option of observation or consideration of surgery, preferably partial nephrectomy | Not mentioned |
| Saudi Urology Association (13) | 2015 | cT1a | RMB strongly recommended before non-surgical options e.g., ablation and AS | Recommended treatment is surgery preferably partial nephrectomy. Active surveillance and ablation not recommended unless significant comorbidities that interdict surgery | Not mentioned |
AS, active surveillance; CT, computed tomography; MRI, magnetic resonance imaging; PN, partial nephrectomy; RMB, renal mass biopsy; SRM, small renal mass; US, ultrasound.