Active surveillance of renal masses in von Hippel-Lindau disease: growth rates and clinical outcome over a median follow-up period of 56 months.

To evaluate the natural outcome of a surveillance strategy for enhancing renal masses associated with von Hippel-Lindau disease (VHL). From January 1988 to June 2011, a watchful waiting strategy was carried out in 16 cases with 42 enhancing renal masses. Clinical data were reviewed to determine tumor growth rate, subsequent interventions, and outcome of follow-up. During a median follow-up of 83 months (range, 55-279), 18 surgical interventions were performed in 13 cases; local recurrence of tumor occurred in 4 cases; 4 patients died (two of metastasis disease, one of CNS Hemangioblastomas with hemorrhage, and one of an unrelated disease) and 12 survived. The median follow-up duration for 42 renal masses was 56 months (range, 19-116 months). The mean tumor growth rate observed was 0.529 cm/year (range, 0.036-1.870 cm/year). The mean growth rate of the tumors larger than 3 cm was 0.573 cm/year, which was not significantly different from that of those smaller tumors (growth rate 0.507 cm/year, P = 0.5905). There was no significant correlation between initial tumor size and growth rate in our cohort with a correlation coefficient of 0.149(P = 0.3480). At the last follow-up, 38 (90.5%) tumors were larger than 3 cm and no metastasis disease developed among tumors ≤4 cm. Progression to metastatic disease was detected in 2 patients. The majority of the enhancing renal masses with VHL disease may still be indolent and do not metastasize during a long period of follow-up even in tumors larger than 3 cm. Metastatic potential during active surveillance appears to be low in VHL patients with Renal tumors ≤4 cm.