Use of delayed intervention for small renal masses initially managed with active surveillance

Introduction: A number of patients who elect active surveillance of their small renal masses (<= 4 cm) subsequently pursue delayed intervention (DI). The indications, timing, and rates of DI have not been well determined prospectively. Materials and methods: Data from Delayed Intervention and Surveillance for Small Renal Masses, a prospective, multi-institutional registry was utilized to evaluate factors associated with DI between 2009 and 2018. Results: Of 371 patients enrolled in AS, 46 (12.4%) pursued DI. Patients who pursued DI spent a median 12 months on surveillance (interquartile range 5.5-23.6), had better functional status (P < 0.01), and had greater median growth rate vs. those who remained on surveillance (0.38 vs. 0.05, P < 0.001). Indications for intervention included growth rate >0.5 cm/y for 23 (50%) patients, patient preference for 22 (47.8%) patients, and qualification for renal transplant in 1 (2.2%) patient. Thirty-two patients (69.6%) underwent nephron-sparing surgery, 5 (10.9%) underwent radical nephrectomy, and 9 (19.6%) underwent percutaneous cryoablation. Renal mass biopsy was utilized in 37 (11.4%) and 15 (32.7%) patients in the AS and DI arms, respectively (P = 0.04). No patients experienced metastatic progression or died of kidney cancer. Conclusions: As nearly 50% of patients pursue DI secondary to anxiety in the absence of clinical progression, comprehensive counseling is essential to determine if patients are suitable for a surveillance protocol. AS remains a safe initial management option for many patients but may not be a durable strategy for patients who are acceptable surgical candidates with an extended life expectancy. DI does not compromise oncologic outcomes or limit treatment options. (C) 2018 Elsevier Inc. All rights reserved.