Clinical question: In patients with small renal masses ≤4 cm, can active surveillance safely defer intervention?
Design: Prospective multicentre registry, not randomized. 497 patients enrolled from 2009–2014: 274 primary intervention and 223 active surveillance; 21 surveillance patients crossed over to delayed intervention.
Overall survival: 92% primary intervention vs 75% active surveillance (P=.06). Cancer-specific survival: 99% vs 100% (P=.3).
Not quantifiable. This is not a randomized treatment comparison. The 5-year OS difference is strongly affected by baseline selection: surveillance patients were older and had greater comorbidity but smaller tumors. Calculating an NNT from these crude OS rates would falsely attribute selection effects to treatment.
In a later 785-patient update, 10-year cancer-specific survival remained essentially identical: 99.2% vs 99.7% for primary intervention vs active surveillance (P=.7).
Patients chose primary intervention or active surveillance. Surveillance progression was defined by growth rate >0.5 cm/year, size >4 cm, metastatic disease or elective crossover. This observational design is particularly important when interpreting overall survival.
DISSRM's central finding is that carefully selected patients with small renal masses can undergo active surveillance with extremely high cancer-specific survival, despite a lower crude overall survival that reflects the older/comorbid surveillance population. The study supports surveillance as an oncologically credible strategy for selected patients, but it does not prove equivalence of surveillance and surgery through randomization.
Pierorazio et al., European Urology 2015
Active surveillance is an accepted option for selected patients with small renal masses, particularly those with substantial competing mortality, comorbidity or limited renal reserve. DISSRM is an observational registry rather than a randomized equivalence trial; decisions should incorporate tumour size/growth, imaging characteristics, renal function, patient preference and feasibility of follow-up. Partial nephrectomy or ablation remains appropriate for patients whose tumour and fitness favour intervention.
DISSRM Registry primary/registry source ↗ · Current guideline guidance ↗