Login to Access Video or Poster Abstract: MP100-03
Sources of Funding: None

Introduction

Cryoablation is a minimally invasive modality for the management of small renal cortical neoplasms. Successful ablation is dependent on achieving target temperatures (i.e. -20°C) that result in tumor cell death. However, in most cases no thermal sensing device is deployed to monitor the temperature. We investigated long-term oncological outcomes following cryoablation using Multi-Point Thermal Sensing (MTS) needles, which allow precise temperature determination at four points along the needle.

Methods

We reviewed 20 cryoablation procedures for renal tumors < 4 cm done between 2005 to 2009; 11 procedures were performed with MTS needles with the goal of obtaining -20°C at the tumor margin, while 9 procedures were done without MTS needles. Patient demographics, tumor characteristics, and operative data were retrieved. Follow up CT or MRI imaging was used to assess recurrence status.

Results

With a mean follow-up of 45 months, none of the 11 MTS patients experienced a recurrence, compared to 4 (44.4%) of the non-MTS patients (p = 0.026). Of the biopsy-confirmed renal cancers, none of the 6 in the MTS group recurred compared to 3 of 6 in the non-MTS group (p = 0.182). Age, gender, tumor size, tumor histopathology, grade, follow-up time, and skin-to-tumor distance were similar between the MTS and non-MTS groups. The MTS group had increased duration of freeze (p = 0.041), increased procedure time (p = 0.020), increased number of cryoprobes placed in order to achieve the targeted temperature (p = 0.049), and a greater ratio of cryoprobes used per cm tumor (p = 0.003).

Conclusions

Using MTS needles, precise target temperatures could be determined during cryoablation of renal tumors. The use of MTS needles was associated with improved oncological outcomes.

Funding

None