Thomas D. Atwell

Image-guided ablation of painful metastatic bone tumors: a new and effective approach to a difficult problem.

Painful skeletal metastases are a common problem in cancer patients. Although external beam radiation therapy is the current standard of care for cancer patients who present with localized bone pain, 20–30% of patients treated with this modality do not experience pain relief, and few further options exist for these patients. For many patients with painful metastatic skeletal disease, analgesics remain the only alternative treatment option. Recently, image-guided percutaneous methods of tumor destruction have proven effective for treatment of this difficult problem. This review describes the application, limitations, and effectiveness of percutaneous ablative methods including ethanol, methyl methacrylate, laser-induced interstitial thermotherapy (LITT), cryoablation, and percutaneous radiofrequency ablation (RFA) for palliation of painful skeletal metastases.

Percutaneous Renal Cryoablation: Experience Treating 115 Tumors

PURPOSE We determined technical feasibility, safety and short-term outcomes following percutaneous renal cryoablation. MATERIALS AND METHODS We performed a retrospective review of 115 renal tumors in 110 patients treated with percutaneous cryoablation. Specific attention was directed to tumor characteristics, hospital course, complications, technical success and treatment success based on followup imaging. RESULTS Mean tumor size was 3.3 cm (range 1.5 to 7.3), including 29 tumors 4.0 cm or larger and 21 tumors in the anterior kidney. Of 90 renal mass biopsies performed 52 (58%) showed renal cell carcinoma. All patients were admitted to the hospital following cryoablation and most (87%) were discharged home the next day (range 1 to 12 days). There were 7 major complications associated with the 113 cryoablation procedures (6%). Technical success was achieved in 112 of the 115 (97%) treated tumors and 3 residual tumors were seen on 3-month followup imaging. There has been no local progression in 80 tumors (100% treatment success) followed 3 months or longer (mean 13.3 months). CONCLUSIONS Percutaneous renal cryoablation is technically feasible and relatively safe. With experience many anterior tumors and tumors larger than 4 cm can be successfully treated. Long-term followup remains necessary to prove treatment durability.

Percutaneous image-guided cryoablation of painful metastases involving bone: multicenter trial.

This study sought to describe the results of a single‐arm multicenter clinical trial using image‐guided percutaneous cryoablation for the palliation of painful metastatic tumors involving bone.

Complications following 573 Percutaneous Renal Radiofrequency and Cryoablation Procedures

PURPOSE To review complications related to percutaneous renal tumor ablation. MATERIALS AND METHODS Prospectively collected data related to renal radiofrequency (RF) ablation and cryoablation procedures performed from May 2000 through November 2010 were reviewed. This included 573 renal ablation procedures performed in 533 patients to treat 633 tumors. A total of 254 RF ablation and 311 cryoablation procedures were performed; eight patients underwent simultaneous RF ablation and cryoablation. The mean age of patients at the time of the procedure was 70 years (range, 24-93 y), and 382 of 573 procedures (67%) were performed in male patients. Complications were recorded according to the Clavien-Dindo classification scheme. Duration of hospitalization was also documented. RESULTS Of the 573 procedures, 63 produced complications (11.0% overall complication rate). There were 66 reported complications, of which 38 (6.6% of total procedures) were Clavien-Dindo grade II-IV major complications; there were no deaths. Major complication rates did not differ statistically (P = .15) between cryoablation (7.7%; 24 of 311) and RF ablation (4.7%; 12 of 254). Of the complications related to cryoablation, bleeding and hematuria were most common. Bleeding during cryoablation was associated with advanced age, increased tumor size, increased number of cryoprobes, and central position (P < .05). Of those treated with RF ablation, nerve and urothelial injury were most common. Mean hospitalization duration was 1 day for RF ablation and cryoablation. CONCLUSIONS Complications related to percutaneous renal ablation are infrequent. Recognition of potential complications and associated risk factors can allow optimization of periprocedural care.

Small (<4 cm) Renal Mass: Differentiation of Angiomyolipoma without Visible Fat from Renal Cell Carcinoma Utilizing MR Imaging

PURPOSE To determine whether a combination of magnetic resonance (MR) parameters can help differentiate small angiomyolipomas (AMLs) without visible fat from renal cell carcinomas (RCCs). MATERIALS AND METHODS This HIPAA-compliant retrospective study received institutional review board approval; 69 men and 42 women (mean age, 59.7 years) with 15 AMLs without visible fat and 104 RCCs underwent MR. The development set consisted of 10 AMLs and 71 RCCs; the validation set consisted of five AMLs and 33 RCCs. T1-weighted fast spin-echo (SE), fat-suppressed T2-weighted fast SE, in- and opposed-phase gradient-echo (GRE), and fat-suppressed three-dimensional T1-weighted spoiled GRE sequences were performed before and after contrast material administration. Tumor signal intensity (SI) was measured. T1 and T2 SI ratio (ratio of tumor to renal cortex SI on T1- and T2-weighted images, respectively), SI index (SII) ([SI(in) 2 SI(opp)]/[SI(in)] × 100; SI(in) and SI(opp) are tumor SI on in- and opposed-phase images, respectively), and arterial-to-delayed enhancement ratio ([SI(art) 2 SI(pre)]/[SI(del) 2 SI(pre)]; SI(pre), SI(art), and SI(del) are tumor SI on unenhanced, arterial phase, and delayed phase three-dimensional T1-weighted spoiled GRE images, respectively) were compared. Combinations of MR parameter threshold levels were constructed from development set and validated with validation set. Sensitivity, specificity, and accuracy for differentiating between AML and RCC were calculated for combinations of MR parameter threshold levels. RESULTS AML had significantly higher T1 SI ratio (P = .04), lower T2 SI ratio (P = .001), higher SII (P = .02), and higher arterial-to-delayed enhancement ratio (P < .001) than RCC. Sensitivity, specificity, and accuracy for combination of T2 SI ratio less than 0.9 and ([SII greater than 20% and T1 SI ratio greater than 1.2] or arterial-to-delayed enhancement ratio greater than 1.5) were 73% (11 of 15), 99% (103 of 104), and 96% (114 of 119), respectively, for differentiating AML from RCC. CONCLUSION A combination of T2 SI ratio less than 0.9 and ([SII greater than 20% and T1 SI ratio greater than 1.2] or arterial-to-delayed enhancement ratio greater than 1.5) was accurate in differentiating AML from RCC.

Incidence of Bleeding After 15,181 Percutaneous Biopsies and the Role of Aspirin

OBJECTIVE The objective of our study was to report the incidence of bleeding after imaging-guided percutaneous core biopsy at a single center using a standardized technique. MATERIALS AND METHODS We performed a retrospective review of percutaneous core biopsies performed at our institution from January 2002 through February 2008. Data were collected at the time of biopsy, and clinical information was obtained 24 hours and 3 months after the biopsy. The specific information that was collected included the results of coagulation studies, aspirin use, the organ biopsied, the size of the biopsy needle, and the number of needle passes. Bleeding complications were defined using the Common Terminology Criteria for Adverse Events (CTCAE, version 3.0) established by the National Cancer Institute. RESULTS Among the 15,181 percutaneous core biopsies performed during the study period, 70 hemorrhages (0.5%) that were CTCAE grade 3 or greater were identified within 3 months of biopsy. The incidence of bleeding in patients taking aspirin within 10 days before biopsy was 0.6% (18/3,195), which was not statistically different compared with the incidence of bleeding in those not taking aspirin (52/11,986, 0.4%; p = 0.34). The incidence of bleeding after liver biopsy was 0.5%; kidney biopsy, 0.7%; lung biopsy, 0.2%; pancreas biopsy, 1.0%; and other biopsy, 0.2%. There were significant associations between major bleeding and serum platelet count and international normalized ratio (p < 0.001), although the association between major bleeding and the size of the biopsy needle was not significant (p = 0.97). CONCLUSION The overall incidence of major bleeding after imaging-guided percutaneous core needle biopsy is low. Recent aspirin therapy does not appear to significantly increase the risk of such bleeding complications.

Usefulness of R.E.N.A.L. Nephrometry Scoring System for Predicting Outcomes and Complications of Percutaneous Ablation of 751 Renal Tumors

PURPOSE We applied the R.E.N.A.L. (radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior and location relative to polar lines) nephrometry scoring system to renal tumors treated with percutaneous ablation to determine whether this score is associated with oncological outcomes and complications. MATERIALS AND METHODS A total of 751 renal tumors were treated at 679 percutaneous ablation sessions in 627 patients at our institution between 2000 and 2012. Of these renal masses 430 (57%) were treated with cryoablation and the remaining 321 were treated with radio frequency ablation. R.E.N.A.L. tumor scores were analyzed to determine the association of the score with ablation treatment outcomes and complications according to Clavien criteria. RESULTS The mean ± SD R.E.N.A.L. nephrometry score of all ablated tumors was 6.7 ± 1.9. Those treated with cryoablation had higher scores than those treated with radio frequency ablation (mean 7.2 ± 1.9 vs 6.1 ± 1.8, p <0.001). We identified a total of 28 local treatment failures (3.7%) in the 751 tumors during a mean computerized tomography/magnetic resonance imaging followup of 27.9 ± 27.8 months. There was a significant association between R.E.N.A.L. nephrometry score and local treatment failure. Mean nephrometry score was 7.6 ± 2.2 vs 6.7 ± 1.9 for tumors with vs without local treatment failure (p <0.001). Of the 679 ablation treatments 38 (5.6%) major (grade 3 or greater) patient complications occurred. There was a significant association between R.E.N.A.L. nephrometry score and major complications. Patients with vs without a major complication had a mean nephrometry score of 8.1 ± 2.0 vs 6.8 ± 1.9 (p <0.001). CONCLUSIONS The R.E.N.A.L. nephrometry scoring system predicts treatment efficacy and complications following percutaneous renal ablation.

Percutaneous Ablation of Renal Masses Measuring 3.0 cm and Smaller: Comparative Local Control and Complications After Radiofrequency Ablation and Cryoablation

OBJECTIVE The purpose of this article is to compare the efficacy and complication rates of percutaneous radiofrequency ablation (RFA) and cryoablation in the treatment of renal masses measuring 3.0 cm and smaller. MATERIALS AND METHODS A retrospective review was performed of 385 patients with 445 tumors measuring 3.0 cm or smaller treated with thermal ablation from 2000 through 2010. Two hundred fifty-six tumors in 222 patients were treated with RFA (mean [± SD] tumor size, 1.9 ± 0.5 cm), and 189 tumors in 163 patients were treated with cryoablation (mean tumor size, 2.3 ± 0.5 cm). Major complications and efficacy as measured by technical success and local tumor recurrence rates were recorded. RESULTS There were five (1.1%) technical failures, including one (0.4%) among tumors treated with RFA and four (2.1%) among tumors treated with cryoablation (p = 0.17). Of the 218 tumors treated with RFA and with follow-up beyond 3 months, seven (3.2%) developed local tumor recurrence, at a mean of 2.8 years after treatment (range, 1.2-4.1 years). Of the 145 tumors treated with cryoablation and with follow-up beyond 3 months, four (2.8%) developed local tumor recurrence at a mean of 0.9 years after treatment (range, 0.3-1.6 years). For biopsy-proven renal cell carcinoma, estimated local recurrence-free survival rates at 1, 3, and 5 years after RFA were 100%, 98.1%, and 98.1%, respectively, compared with 97.3%, 90.6%, and 90.6%, respectively, after cryoablation (p = 0.09). Major complications occurred after 4.3% (10/232) of RFAs and 4.5% (8/176) of cryoablation procedures (p = 0.91). CONCLUSION RFA and cryoablation are both effective in the treatment of renal masses measuring 3 cm or smaller. Major complications with either procedure are infrequent.

Percutaneous Cryoablation of Large Renal Masses: Technical Feasibility and Short-Term Outcome

OBJECTIVE This retrospective study was performed to assess the feasibility, safety, and short-term outcome of percutaneous cryoablation of large solid renal tumors. MATERIALS AND METHODS We reviewed 40 percutaneous cryoablation procedures performed on 40 patients with renal tumors 3 cm in diameter or larger. All patients underwent cryoablation with CT monitoring. Technical success was defined by extension of the ice ball beyond the tumor margin and postablation imaging findings of no contrast enhancement in the area encompassing the original tumor. Complications meeting grade 3 of the National Cancer Institute Common Terminology Criteria for Adverse Events were recorded. RESULTS Mean +/- SD tumor diameter was 4.2 +/- 1.1 cm (range, 3.0-7.2 cm). Technical success was achieved in 38 (95%) of 40 cryoablation procedures. There was one grade 3 adverse event (3% rate of significant complications). Follow-up images obtained 3 months or longer (mean, 9 +/- 6 months; range, 3-22 months) after ablation were available for 26 (65%) of the 40 patients. No local tumor recurrence or tumor progression was found. CONCLUSION Percutaneous cryoablation of renal tumors measuring 3 cm or larger is technically feasible and relatively safe. Short-term follow-up results are encouraging, although long-term follow-up is necessary to assess true treatment efficacy.

Palliation of Painful Metastatic Disease Involving Bone With Imaging-Guided Treatment: Comparison of Patients' Immediate Response to Radiofrequency Ablation and Cryoablation

OBJECTIVE The purpose of this article was to compare periprocedural analgesic requirements and hospital length of stay for treatment of patients with painful metastatic tumors involving bone using either percutaneous radiofrequency ablation (RFA) or cryoablation. MATERIALS AND METHODS A retrospective review was conducted of patients who underwent either imaging-guided cryoablation or imaging-guided RFA for painful metastatic tumors involving bone. The total analgesic usage for 24 hours after the procedure was expressed as a standard morphine-equivalent dose. Analgesic usage at admission served as a baseline for comparison. Total hospital stay was used as an additional measurement of procedure-related morbidity. RESULTS Fifty-eight patients underwent either cryoablation (n = 36) or RFA (n = 22) for painful metastatic tumors involving bone. Twenty-two primary tumors were treated. The most common treatment site was the pelvis (n = 31). There was no significant difference between the two groups with regard to tumor histologic type (p = 0.52) and location (p = 0.72). The median tumor diameter was 4.4 cm for the cryoablation group and 5.0 cm for the RFA group (p = 0.63). Pretreatment pain scores, measured on a scale of 0 to 10, were not significantly different between the two groups: 6.5 for cryoablation and 6.0 for RFA (p = 0.78). Analgesic use in the 24 hours immediately after the procedure decreased significantly by 24 morphine-equivalent doses after cryoablation, whereas it increased by a median of 22 morphine-equivalent doses after RFA (p = 0.03). Total hospital length of stay for patients undergoing cryoablation was a median of 2.5 days less than that for patients receiving RFA (p = 0.003). CONCLUSION The use of cryoablation compared with RFA is associated with a greater reduction in analgesic dose and shorter hospital stays after the procedure in the perioperative time frame.