Percutaneous cryoablation of renal tumors adjacent to critical structures: impact of adjacent organ type on local tumor control

Background Renal cell carcinomas (RCCs) adjacent to critical structures can be safely treated using percutaneous cryoablation with adjunctive techniques. However, there are only a few reports describing the factors affecting local tumor control after percutaneous cryoablation for such RCCs. Purpose To evaluate the factors affecting local tumor control in the percutaneous cryoablation of RCCs adjacent to critical structures. Material and Methods A total of 403 tumors from 328 patients were retrospectively reviewed. Patients with histologically proven RCCs adjacent to critical structures with at least 1 year of follow-up after treatment were included. Hereditary RCCs were excluded. Of the 403 tumors, 40 met the criteria. Owing to the tumor location, all procedures were performed using adjunctive techniques. Baseline, perioperative, and follow-up data were collected and factors affecting local tumor progression were evaluated. Comparisons between groups with and without local tumor progression were performed using Fisher's exact test or Wilcoxon's rank sum test. Results The median follow-up was 1289.5 days. Local tumor progression was observed in 7/40 (17.5%) patients. Univariate analysis revealed that significant factors affecting local tumor progression were situated adjacent to the ureter ( P = 0.005), requiring adjunctive techniques other than hydro- and/or pneumo-dissection ( P = 0.005), as well as the distance between tumors and critical structures ( P = 0.04). The ice-ball margin tended to be smaller in the group with local tumor progression but this was not significant ( P = 0.07). Conclusion Renal tumors adjacent to the ureter may result in local tumor progression after cryoablation compared with tumors adjacent to other organs.