Percutaneous Cryoablation of Renal Tumors: Is It Time for a New Paradigm Shift?

PURPOSE: To retrospectively assess long-term outcomes of percutaneous renal cryoablation, including factors affecting complications and local recurrence rates. MATERIALS AND METHODS: A total of 357 computed tomographic (CT) fluoroscopy-guided percutaneous cryoablation procedures were performed for 382 masses in 302 outpatients; 347 were biopsy-proven renal-cell carcinoma (RCC) or Bosniak category > III masses (n = 28). Benign pathologic conditions (n = 18) or metastatic non-RCC disease (n = 17) were included to analyze procedural complication rate, but recurrence rates, tumor staging, and nephrometry score were limited to RCCs. The average tumor diameter was 2.9 cm (range, 1-10.3 cm), and median nephrometry score for RCC was 8 (mean, 7.4). Protection of adjacent vital structures was performed in 34% of procedures (n = 121), and ureteral stent placement was performed for 9.2% (n = 33). All major complications were graded per surgical Clavien-Dindo criteria. RESULTS: The average CT-visible cryoablation zone diameter was 5 cm (range, 2.5-10.5 cm). Grade ≥ 3 complications occurred in 2.8% of procedures (n = 10), and appeared related to only high nephrometry scores (P = .0086) and larger tumors (P = .0034). No significant changes in renal function before and after the procedure were noted (P = .18). At a mean follow-up of 31.8 months, the local tumor recurrence rate was 3.2% (11 of 347) for RCC, and no significant difference was noted between tumors larger or smaller than 3 cm (P = .15). The difference reached significance only among the small number of stage ≥ T2 RCC tumors (P = .0039). CONCLUSIONS: Long-term follow-up of percutaneous renal cryoablation demonstrates low recurrence rates with preserved renal function, even for patients with high nephrometry scores and body mass index, assuming thorough cytotoxic technique and protection measures.

Evolution and implementation of radiographic response criteria in neuro-oncology.

Radiographic response assessment in neuro-oncology is critical in clinical practice and trials. Conventional criteria, such as the MacDonald and response assessment in neuro-oncology (RANO) criteria, rely on bidimensional (2D) measurements of a single tumor cross-section. Although RANO criteria are established for response assessment in clinical trials, there is a critical need to address the complexity of brain tumor treatment response with multiple new approaches being proposed. These include volumetric analysis of tumor compartments, structured MRI reporting systems like the Brain Tumor Reporting and Data System, and standardized approaches to advanced imaging techniques to distinguish tumor response from treatment effects. In this review, we discuss the strengths and limitations of different neuro-oncology response criteria and summarize current research findings on the role of novel response methods in neuro-oncology clinical trials and practice.

Percutaneous cryoablation of hepatic tumors: long-term experience of a large U.S. series.

PURPOSE: To report our long-term experience with percutaneous cryotherapy for primary and metastatic liver tumors, including historical perspectives on complications over time and local recurrence rates. MATERIALS AND METHODS: Following IRB approval under HIPAA compliance, 342 CT fluoroscopic-guided, percutaneous cryotherapy procedures were performed for 443 masses in 212 outpatients with hepatocellular carcinoma (HCC; N = 36), or metastatic disease (N = 176), grouped as colorectal carcinoma (CRC) and non-CRC metastases. Tumor and ablation sizes were noted in relation to adjacent vasculature. All complications were graded according to standardized criteria. Patients were followed by CT and/or MRI at 1, 3, 6, 12, 18, 24 months and yearly thereafter. Local recurrences were defined as either "procedural" within the ice ablation zone, or "satellite" within 1 cm of the ablation rim to evaluate recurrence patterns. RESULTS: Average tumor diameter of 2.8 cm was treated by average cryoprobe number of 4.5, which produced CT-visible ice ablation zone diameters averaging 5.2 cm. Grade >3 complications were primarily hematologic [N = 20/342; (5.8%)], and appeared related to pre-procedural anemia/thrombocytopenia, carcinoid tumor type, and large ablation volumes. No significant central biliary leak, strictures, or bilomas were noted. At a mean follow-up of 1.8 years, local tumor recurrences were 5.5%, 11.1%, and 9.4% for HCC, CRC, and non-CRC metastases, respectively, consisting mainly of satellite foci. No significant difference was noted for local recurrences near major blood vessels or tumors >3 cm diameter. CONCLUSIONS: Percutaneous hepatic cryotherapy is a well-visualized, safe procedure that produces very low local recurrence rates, even for tumors near vasculature and diameters over 3 cm. Cryoablation deserves to be in the armamentarium of percutaneous hepatic ablation, especially with careful patient selection for tumors <4 cm and patients with platelet counts >100,000. Percutaneous hepatic cryoablation represents a highly flexible technique with particular benefits near central biliary structures and/or adjacent crucial structures.