Scientific Abstracts: Thoracic, Renal, and Bone
Objective: To assess the theoretical risk of the heat-sink effect on treatment failure of microwave ablation for central renal tumors.
Methods: A retrospective analysis of 92 patients (M:F= 69:23, mean age = 75 yrs) was performed between December 2008 to June 2019. Central renal tumors that were located within 5mm of the ureter or renal sinus were included in this study. Baseline patient and tumor demographics data were collected. Assessment of the rates of complications, residual disease and local recurrence was performed to evaluate treatment outcomes.
Results: Of the 92 biopsy-proven cT1N0M0 RCC, 23/92 (25%) were central tumors and 69/92 (75%) were non-central tumors. Central tumors are associated with higher tumor complexity as indicated by the RENAL nephrometry score (p = 0.01). Ablation of central tumors is associated with a significantly higher rate of hematomas (30% vs 9%, p = 0.003) and urethral injury (9% vs 0%, p = 0.0001). Central tumors, compared to non-central tumors, show significantly more residual disease (26% vs 4%, p = 0.0001), but similar rates of local recurrence (9% vs 4%, p = 0.25).
Conclusions: Rates of residual disease and local recurrence are particularly high for central renal tumors following microwave ablation. Careful pre-treatment assessment and frequent post-treatment surveillance imaging are warranted.