Rates of volume reduction after selective arterial embolization for renal angiomyolipoma

Abstract

Purpose

To characterize temporal patterns of renal angiomyolipoma volume reduction after selective arterial embolization and identify factors predictive of reduction rates

Materials and methods

Records of patients undergoing renal angiomyolipoma embolization from July 2001 to July 2023 at our center were retrospectively reviewed. Tumor measurements were extracted from available imaging, and lipid content was scored based on tumor attenuation characteristics. Rates of volume reduction were compared for tumors at different follow-up intervals. The primary outcome was monthly tumor volume reduction.

Results

Forty-four patients were identified who underwent 77 embolizations for 54 tumors. Of these, 32 patients had available volume data and were included in the analysis of our primary outcome. Tumor volumes decreased significantly faster during the first 6 months after embolization (7.4% per month) compared to years 2 and 3 of follow-up (0.3% per month, P = 0.01 and <0.1% per month, P = 0.01, respectively). Mean tumor size reduction within the first 6 months of initial embolization was 25% lower for patients who ultimately had repeat embolization compared to single-embolization patients. Within the first 6 months, older patients experienced 0.9% lower monthly volume reduction per additional year of age.

Conclusions

Embolized tumors in this cohort involuted rapidly during the first 6 months of follow-up, then stabilized, with the rate of volume reduction approaching 0% per month after 2 years. These data contribute to the understanding of angiomyolipoma embolization outcomes and may help providers avoid unnecessary embolization in patients with stable smaller tumors after 1 to 2 years.