Impact of tumor histology and grade on treatment success of percutaneous renal cryoablation

Background

We analyzed oncological outcomes in patients who underwent percutaneous renal cryoablation (PRC) with documented renal cell carcinoma (RCC) by perioperative biopsy.

Methods

Multicenter retrospective analysis of 153 patients [median follow-up 48 months] who underwent PRC from 09/2005 to 08/2014 was performed. We divided the cohort into patients who developed recurrence versus no recurrence. Kaplan–Meier analyses examined recurrence-free survival (RFS) according to grade and histology. Multivariable analysis (MVA) was performed to identify factors associated with tumor recurrence.

Results

One hundred and fifty-three patients were analyzed [18 patients (11.8 %) with recurrence and 135 (88.2 %) patients without recurrence]. There were no differences between the groups with respect to demographics, RENAL score, and number of probes utilized. Recurrence group had larger tumor size (3.1 vs. 2.4 cm; p = 0.011), upper pole tumor location (p = 0.016), and greater proportions of high-grade tumor (33 vs. 0.7 %; p < 0.001) and clear cell histology (77.8 vs. 45.9 %; p = 0.011). Four-year RFS was 100 versus 80 % for grade 1 versus grade 2/3 tumors (p = 0.0002), and 97 versus 88 % for other RCC versus clear cell RCC (p = 0.07). MVA demonstrated tumor size >3 cm (OR 2.46; p = 0.019), clear cell histology (OR 2.12; p = 0.027), and high tumor grade (OR 2.33, p < 0.001) as independent risk factors associated with tumor recurrence.

Conclusions

Association of higher grade and clear cell histology with recurrence and progression suggests need for increased emphasis on preoperative risk stratification by biopsy, with grade 1 and non-clear cell RCC being associated with improved treatment success than higher grade and clear cell RCC.