Soft-tissue cryoablation in diffuse locations: feasibility and intermediate term outcomes.

PURPOSE: To assess whether diverse tumor location(s) show differences in percutaneous cryoablation (PCA) outcomes of cancer control, morbidity, and ablation volume reduction for many soft-tissue tumor types. MATERIALS AND METHODS: A total of 220 computed tomography (CT)- and/or ultrasonography-guided percutaneous cryotherapy procedures were performed for 251 oligometastatic tumors from multiple primary cancers in 126 patients. Tumor location was grouped according to regional sites: retroperitoneal, superficial, intraperitoneal, bone, and head and neck. PCA complications were graded according to Common Terminology Criteria for Adverse Events (version 4.0). Local tumor recurrence and involution were calculated from ablation zone measurements, grouped into 1-, 3-, 6-, 12-, 18-, and 24-month (or later) statistical bins. RESULTS: Tumor and procedure numbers for each site were 75 and 69 retroperitoneal, 76 and 62 superficial, 39 and 32 intraperitoneal, 34 and 34 bone, and 27 and 26 head and neck. Average diameters of tumor and visible ice during ablation were 3.4 and 5.5 cm, respectively. Major complications (ie, grade >3) attributable to PCA occurred after five procedures (2.3%). At 11 months average follow-up (range, 0-82 mo), a 10% total recurrence rate (26 of 251) was noted; three occurred within the ablation zone, for a local progression rate of 1.2%. Average time to recurrence was 4.9 months, and, at 21 months, the initial ablation zone had reduced in volume by 93%. CONCLUSIONS: CT-guided PCA is a broadly safe, effective local cancer control option for oligometastatic disease with soft-tissue tumors in most anatomic sites. Other than bowel and nerve proximity, PCA also shows good healing if proper visualization and precautions are followed.

Percutaneous cryoablation of metastatic lesions from non-small-cell lung carcinoma: initial survival, local control, and cost observations.

PURPOSE: To assess feasibility, complications, local tumor recurrences, overall survival (OS), and estimates of cost effectiveness for multisite cryoablation (MCA) of oligometastatic non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS: A total of 49 computed tomography- and/or ultrasound-guided percutaneous MCA procedures were performed on 60 tumors in 31 patients (19 women and 12 men) with oligometastatic NSCLC. Average patient age was 65 years. Tumor location was grouped according to common metastatic sites. Median OS was determined by Kaplan-Meier method and defined life-years gained (LYGs). Estimates of MCA costs per LYG were compared with established values for systemic therapies. RESULTS: Total numbers of tumors and cryoablation procedures for each anatomic site were as follows: lung, 20 and 18; liver, nine and seven; superficial, 12 and 11; adrenal, seven and seven; paraaortic/isolated, two and two; and bone, 10 and seven. A mean of 1.6 procedures per patient were performed, with a median clinical follow-up of 11 months. Major complication and local recurrence rates were 8% (four of 49) and 8% (five of 60), respectively. Median OS for MCA was 1.33 years, with an estimated 1-year survival rate of approximately 53%. MCA appeared cost-effective even when added to the cost of best supportive care or systemic regimens, with an adjunctive cost-effectiveness ratio of $49,008-$87,074. CONCLUSIONS: MCA was associated with very low morbidity and local tumor recurrence rates for all anatomic sites, and possibly increased OS. Even as an adjunct to systemic therapies, MCA appeared cost-effective for palliation of oligometastatic NSCLC.

Percutaneous cryoablation of metastatic renal cell carcinoma for local tumor control: feasibility, outcomes, and estimated cost-effectiveness for palliation.

PURPOSE: To assess complications, local tumor recurrences, overall survival (OS), and estimates of cost-effectiveness for multisite cryoablation (MCA) of oligometastatic renal cell carcinoma (RCC). MATERIALS AND METHODS: A total of 60 computed tomography- and/or ultrasound-guided percutaneous MCA procedures were performed on 72 tumors in 27 patients (three women and 24 men). Average patient age was 63 years. Tumor location was grouped according to common metastatic sites. Established surgical selection criteria graded patient status. Median OS was determined by Kaplan-Meier method and defined life-years gained (LYGs). Estimates of MCA costs per LYG were compared with established values for systemic therapies. RESULTS: Total number of tumors and cryoablation procedures for each anatomic site are as follows: nephrectomy bed, 11 and 11; adrenal gland, nine and eight; paraaortic, seven and six; lung, 14 and 13; bone, 13 and 13; superficial, 12 and nine; intraperitoneal, five and three; and liver, one and one. A mean of 2.2 procedures per patient were performed, with a median clinical follow-up of 16 months. Major complication and local recurrence rates were 2% (one of 60) and 3% (two of 72), respectively. No patients were graded as having good surgical risk, but median OS was 2.69 years, with an estimated 5-year survival rate of 27%. Cryoablation remained cost-effective with or without the presence of systemic therapies according to historical cost comparisons, with an adjunctive cost-effectiveness ratio of $28,312-$59,554 per LYG. CONCLUSIONS: MCA was associated with very low morbidity and local tumor recurrence rates for all anatomic sites, with apparent increased OS. Even as an adjunct to systemic therapies, MCA appeared cost-effective for palliation of oligometastatic RCC.

Percutaneous Cryoablation of Metastatic Lesions from Colorectal Cancer: Efficacy and Feasibility with Survival and Cost-Effectiveness Observations.

PURPOSE: To assess feasibility, complications, local tumor recurrences, overall survival (OS) and estimates of cost-effectiveness for multi-site cryoablation (MCA) of oligo-metastatic colorectal cancer (mCRC) in a prospective study. MATERIALS AND METHODS: 111 CT and/or US-guided percutaneous MCA procedures were performed on 151 tumors in 59 oligo mCRC patients. Mean patient age was 63 years (range 21-92 years), consisting of 29 males and 30 females. Tumor location was grouped according to common metastatic sites. Median OS was determined using the Kaplan-Meier. Estimates of MCA costs per LYG were compared to historical values for systemic therapies. RESULTS: A mean 1.9 MCAs per patient were performed with a median clinical follow-up of 12 months. Major complication and local recurrence rates were 8% (9/111) and 12% (18/151), respectively. Median overall-survival (OS) was 23.6 months with an estimated 3-year survival rate of ~30%. Cryoablation remained cost effective with or without the presence of systemic therapies, with an adjunctive cost-effectiveness ratio (ACER) of $39,661-$85,580 per LYG. CONCLUSIONS: Multi-site cryoablation had very low complication and local recurrence rates, and was able to provide local control even for diverse soft tissue locations. Even as an adjunct to systemic therapies, MCA appeared cost-effective, with apparent increased survival.

Lethal isotherms of cryoablation in a phantom study: effects of heat load, probe size, and number.

PURPOSE: To assess the effects on the proportions of lethal ice (ie, colder than -30 degrees C) in phantoms with different heat loads created by varying the size and number of cryoprobes spaced 2 cm apart. MATERIALS AND METHODS: Thermocouples at 0.5-, 1.0-, and 1.5-cm intervals from 1.7- or 2.4-mm-diameter cryoprobes were held by jigs accommodating a maximum of four cryoprobes. Agar phantoms (N = 24) used three sets of baseline temperatures: approximately 6 degrees C, 24 degrees C, and 39 degrees C. Temperatures during 15-minute freeze cycles were correlated with actual thermocouple locations seen within the ice by computed tomography (CT). Diameters and surface areas of the -30 degrees C lethal isotherm were assessed over time as percentages of the overall ice ball. RESULTS: The high-heat load phantom experiments (39 degrees C) showed the greatest impact on lethal zones by percentage for all probe configurations. At 15 minutes, single-, double-, triple-, and quadruple-probe arrangements of 2.4-mm cryoprobes had average lethal ice diameters of 1.2, 3.3, 4.1, and 4.9 cm, respectively, comprising 13%, 46%, 51%, and 56% surface areas of lethal ice, respectively. Surface areas and diameters of lethal ice made by 1.7-mm cryoprobes were 71% and 84% of those made by 2.4-mm cryoprobes, respectively. Lethal ice resides less than 1 cm behind the leading edge for nearly all probe configurations and heat loads. CONCLUSIONS: Single cryoprobes create very low percentages of lethal ice. Multiple cryoprobes overcome the high heat load of body temperature phantoms and help compensate for the lower freeze capacity of thinner cryoprobes.