Treatment on active surveillance of small renal masses: Progression vs. preference

Active surveillance (AS) of small renal masses (SRM) is increasingly recognized as a safe option. A recent U.S. study found that half of patients receiving treatment on AS were for preference, but these findings may not be generalizable to other jurisdictions and healthcare models. We aimed to investigate AS failure rates and causes among a contemporary biopsy-evaluated cohort in Canada.

A retrospective review was performed of SRM patients on AS undergoing treatment at our tertiary care center (1999-2018). All patients had undergone renal biopsy and been diagnosed with renal cell carcinoma (RCC). Demographic and clinical parameters surrounding the decision to treat were extracted from chart review. Indications for treatment were dichotomized into clinical (radiographical) progression or preference. Qualitative assessment of clinic notes confirmed treatment indication. Ethics approval was obtained.

A total of 38 SRM-RCC patients who underwent treatment on AS were identified, of which 29 had been on AS ≥1 year. Most (75.9%) were male and the mean age beginning AS was 65.9±9.0 years. Most patients had clear-cell RCC with low-grade disease. Seventeen of 29 (58.6%) patients experienced clinical progression after 3.82 (2.57-7.16) years, whereas preference accounted for 12/29 (41.4%) after 2.22 (1.69-3.53) years (time-to-treatment p=0.032). The longest duration on AS was 14.2 years prior to clinical progression. No patients had metastatic progression before treatment.

Two-fifths of patients received treatment for preference and at a much higher rate vs. clinical progression. These findings suggest a clinical gap where effective patient counselling prior to and during AS may improve adherence.