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Active Surveillance for Risk Stratification of All Small Renal Masses Lacking Predefined Clinical Criteria for
Arun R Menon1, Ahmed A Hussein1,2, Kristopher M Attwood3
1Department of Urology, Roswell Park Comprehensive Cancer Center, Buffalo, New York.
Purpose:
Despite general indolence of small renal masses and no known adversity from treatment delays, broad usage of active surveillance as a means to risk-stratify patients with small renal masses for more selective treatment has not been studied. We describe outcomes for a novel approach in which active surveillance was recommended to all patients with small renal masses lacking predefined progression criteria for intervention.
Materials And Methods:
All nondialysis dependent patients with nonmetastatic small renal masses seen by 1 urologist at a comprehensive cancer center during January 2013-September 2017 were managed with active surveillance if standardized progression criteria for intervention were absent, with delayed intervention recommended only upon progression criteria for intervention development. Progression criteria for intervention were defined prospectively as small renal mass-related symptoms, unfavorable histology, cT3a stage or either of the following without benign neoplastic biopsy histology: longest tumor diameter >4 cm; growth rate >5 mm/year for longest tumor diameter ≤3 cm or >3 mm/year for longest tumor diameter >3 cm.
Results:
In all, 96% (123/128) of patients with small renal masses lacked progression criteria for intervention at presentation and underwent active surveillance. With median/mean 31/34 months followup, none developed metastasis and 30% (37/123) developed progression criteria for intervention, 78% (29/37) of whom underwent delayed intervention. One (1%) patient crossed over to delayed intervention without progression criteria for intervention. Three-year progression criteria for intervention-free and delayed intervention-free rates were 72% and 75%, respectively. Delayed intervention resections were enriched (62%) for pT3 and/or nuclear grade 3-4 malignant pathology, with no benign resections.
Conclusions:
Active surveillance using predefined progression criteria for intervention in otherwise unselected patients with small renal masses allows intervention to be focused on at-risk small renal masses with common adverse pathology, avoiding treatment for most patients with small renal masses. Long-term delayed intervention and oncologic safety require study.
Insights
Active surveillance for small renal masses is effective, avoiding treatment for most patients. This approach focuses interventions on high-risk tumors, but long-term safety needs further study.
Area of Science:
- Urology
- Oncology
- Nephrology
Background:
- Small renal masses are often indolent, with no known harm from delayed treatment.
- Active surveillance is not widely used for risk-stratifying patients with small renal masses.
- Selective treatment based on risk stratification is a potential strategy for managing small renal masses.
Purpose of the Study:
- To evaluate the outcomes of a novel active surveillance approach for small renal masses.
- To assess the feasibility of recommending active surveillance to all patients with small renal masses lacking predefined intervention criteria.
- To determine if active surveillance can help risk-stratify patients for selective treatment.
Main Methods:
- A prospective study of non-dialysis dependent patients with nonmetastatic small renal masses.
- Active surveillance was recommended for patients lacking predefined progression criteria for intervention.
- Progression criteria included symptoms, unfavorable histology, advanced stage, tumor size, or growth rate.
Main Results:
- 96% of patients with small renal masses initially met criteria for active surveillance.
- No patients developed metastasis during a median follow-up of 31 months.
- 30% of patients developed progression criteria, with 78% undergoing delayed intervention, predominantly for high-grade malignant pathology.
Conclusions:
- Active surveillance with predefined criteria effectively identifies small renal masses requiring intervention.
- This strategy avoids treatment for most patients, focusing resources on high-risk tumors.
- Long-term oncologic safety and delayed intervention outcomes require further investigation.
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