Active surveillance feasible for certain patients with small renal masses suspicious for RCC

Select patients with small renal masses (SRM) suspicious for clinical stage T1a (≤4 cm) renal cell carcinoma (RCC) can be effectively managed with active surveillance.

Long-term outcomes from a comparative study shared during the 2020 Society of Urologic Oncology Annual Meeting showed that cancer-specific survival was noninferior for active surveillance compared with primary intervention in this population.¹

Overall survival (OS) was found to be worse in the active surveillance group, signaling both measured and unmeasured competing risks of mortality in the patient population.

“[Active surveillance] is not inferior to [primary intervention] for carefully selected patients with SRM suspicious for renal cell carcinoma,” wrote the researchers. “The difference in OS between [active surveillance] and [primary intervention] is mostly attributable to the increased risk of death from competing causes among [active surveillance] patients.”

Of the 862 patients enrolled in the study, 785 patients had follow-up data available. In total, 434 patients (55.3%) chose active surveillance and 351 patients (44.7%) chose primary intervention. Progression-free survival (PFS) at 7 years was 62.1% for patients on active surveillance, with 76.4% of progressions due to a growth rate of greater than 0.5 cm/year.

The data showed that 71 of the 434 patients who chose active surveillance (16.4%) crossed over to delayed intervention. The median follow-up time was 3.3 years (IQR, 1.5-6.6), with 292 patients (37.2%) followed for 5 years or more. While there was no difference in cancer-specific survival for active surveillance and primary intervention patients (P = .6), active surveillance patients saw worse OS compared to primary intervention patients (P < .001).

“Elevated growth rate predicts [delayed intervention] but does not impact biological outcomes, including adverse pathology, recurrence, or CSS rates,” wrote the researchers. “Increasing tumor size at enrollment and throughout [active surveillance] predicts [delayed intervention] and biological outcomes. Tumor size should be considered the primary trigger for DI in patients with SRM.”

This multi-institutional comparative study prospectively enrolled patients from 2009-2019 with SRM who underwent active surveillance or primary intervention. Both primary and secondary outcomes were analyzed with the Kaplan-Meier survival analysis and a log-rank test.

The primary end points for the data were CSS and OS, with secondary end points of PFS and recurrence-free survival. The main objective of the research was to report on the 10-year outcomes of patients enrolled in the Delayed Intervention and Surveillance for Small Renal Masses registry.

Currently, active surveillance remains underutilized as an alternative option to primary intervention, employed in only 10-20% of eligible patients. The lack of strong, prospective data regarding this strategy is cause for such underutilization.

Looking ahead, the researchers recommend that “a priori definitions of progression, including growth rate, should be re-considered.”

Reference

1. Cheaib JG, Patel HD, Alam R, et al. Active Surveillance versus Primary Intervention for Clinical T1a Kidney Tumors: Ten-Year Experience of the DISSRM Prospective Comparative Study. Presented at: 21st Annual Meeting of the Society of Urologic Oncology; December 3, 2020. Poster 96.