Ronald J. Zagoria

Oncologic Efficacy of CT-Guided Percutaneous Radiofrequency Ablation of Renal Cell Carcinomas

OBJECTIVE A single institutions experience with CT-guided percutaneous radiofrequency ablation of biopsy-proven renal cell carcinomas (RCCs) was studied to determine the disease-free survival and complication rate. MATERIALS AND METHODS Data from 125 RCCs in 104 patients treated with curative intent was reviewed. Radiofrequency ablation treatments were performed using conscious sedation and local anesthesia. Patients were followed with contrast-enhanced CT or MRI. Tumor control was defined as the absence of contrast enhancement in the tumor on CT or MRI. RESULTS Tumor size ranged from 0.6 to 8.8 cm (mean, 2.7 cm; SD, 1.5 cm). Of the 125 treated tumors, 116 (93%) were completely ablated (109 in a single ablation session, seven after a second ablation session) with a mean follow-up interval of 13.8 months. All 95 RCCs smaller than 3.7 cm were completely ablated, and 21 (70%) of 30 larger tumors were completely ablated, with nine showing evidence of residual viable tumor on follow-up scans. Tumor size smaller than 3.7 cm was significantly associated with achieving complete tumor eradication (p < 0.001). With each 1-cm increase in tumor diameter over 3.6 cm, the likelihood of tumor-free survival decreased by a factor of 2.19 (p < 0.001). There were 8 (8%) complications, none of which resulted in long-term morbidity. CONCLUSION CT-guided percutaneous radiofrequency ablation is a safe method to treat small RCCs. This study indicates that radiofrequency ablation can reliably eradicate RCCs smaller than 3.7 cm. Treatment of larger RCCs will result in an increased risk of residual RCC.

Phase II Trial of Radio Frequency Ablation of Renal Cancer: Evaluation of the Kill Zone

PURPOSE We report on the pathological evaluation of renal tumors after intraoperative radio frequency ablation performed immediately before surgical nephrectomy. MATERIALS AND METHODS Ten patients with renal tumors were enrolled in a prospective, Institutional Review Board approved phase II trial of radio frequency ablation. Following surgical exposure of the kidney a single 12-minute radio frequency ablation of the tumor was performed using the Radionics Cool-tip RF Radio Frequency Ablation System (Radionics, Burlington, Massachusetts). The tumor was then excised via radical or partial nephrectomy. Gross and histological evaluations of the tumor were performed, including evaluation with nicotinamide adenine dinucleotide vital staining. RESULTS All 10 tumors were confirmed histologically to be renal cell carcinoma. Mean tumor size was 3.2 cm. (range 1.4 to 8.0). Of the 10 tumors 8 were completely ablated with a mean treatment margin of 6.75 mm. (range 2 to 13). Of the 2 tumors that were incompletely treated 1 never attained a temperature sufficient for tissue destruction and the other measured 8 cm., far exceeding the expected ablation volume of treatment protocol. CONCLUSIONS This study represents the initial report of the histological outcome of saline cooled radio frequency ablation of renal tumors. Our data indicate that it can completely destroy renal cancers while transmitting minimal collateral damage to surrounding renal parenchyma. Further investigation is required to determine long-term oncological outcome.

Long-term outcomes after percutaneous radiofrequency ablation for renal cell carcinoma.

OBJECTIVES To assess the long-term oncological efficacy of radiofrequency ablation (RFA) for treatment of renal cell carcinoma (RCC). METHODS In this institutional review board-approved, retrospective study, the records and imaging studies for all RCC patients treated with percutaneous RFA before 2005 were reviewed and analyzed. RESULTS A total of 48 RCCs in 41 patients were treated with RFA. Median size of RCC treated was 2.6 cm (range: 0.7-8.2 cm). Of the 48 treated RCCs, 5 (12%) had recurrent tumor after a single ablation session. The median size of the index lesion in the cases with recurrence was 5.2 cm (interquartile range [IQR]: 4-5.3) compared with 2.2 cm (IQR: 1.7-3.1, P = .0014) without local recurrence. There were no recurrences when RCCs less than 4 cm were treated. Seventeen (41%) patients with 18 treated RCCs died during the follow-up period at a median time of 34 (IQR: 10-47) months. One patient (2%) died of metastatic RCC, whereas 16 died of unrelated causes. Twenty-four patients with 30 RCCs treated with RFA survived. For the remaining 30 RCCs, median follow up was 61 months (IQR: 54-68). No patients in this group of survivors had metastatic RCC, 1 had recurrence diagnosed at 68 months. The long-term recurrence-free survival rate was 88% after RFA. CONCLUSIONS RFA can result in durable oncological control for RCCs less than 4 cm. RFA is an effective treatment option for patients with RCCs less than 4 cm who are poor surgical candidates. For patients with larger RCCs alternative treatments should be considered.

MR Urography: Techniques and Clinical Applications

Magnetic resonance (MR) urography comprises an evolving group of techniques with the potential for allowing optimal noninvasive evaluation of many abnormalities of the urinary tract. MR urography is clinically useful in the evaluation of suspected urinary tract obstruction, hematuria, and congenital anomalies, as well as surgically altered anatomy, and can be particularly beneficial in pediatric or pregnant patients or when ionizing radiation is to be avoided. The most common MR urographic techniques for displaying the urinary tract can be divided into two categories: static-fluid MR urography and excretory MR urography. Static-fluid MR urography makes use of heavily T2-weighted sequences to image the urinary tract as a static collection of fluid, can be repeated sequentially (cine MR urography) to better demonstrate the ureters in their entirety and to confirm the presence of fixed stenoses, and is most successful in patients with dilated or obstructed collecting systems. Excretory MR urography is performed during the excretory phase of enhancement after the intravenous administration of gadolinium-based contrast material; thus, the patient must have sufficient renal function to allow the excretion and even distribution of the contrast material. Diuretic administration is an important adjunct to excretory MR urography, which can better demonstrate nondilated systems. Static-fluid and excretory MR urography can be combined with conventional MR imaging for comprehensive evaluation of the urinary tract. The successful interpretation of MR urographic examinations requires familiarity with the many pitfalls and artifacts that can be encountered with these techniques.

CAN NONCONTRAST HELICAL COMPUTED TOMOGRAPHY REPLACE INTRAVENOUS UROGRAPHY FOR EVALUATION OF PATIENTS WITH ACUTE URINARY TRACT COLIC

The objective of this study was to determine whether helical computed tomography (CT) performed without oral or intravenous contrast agents is accurate in the evaluation of patients with suspected acute renal colic. One hundred consecutive patients with suspected renal colic or ureteral colic were referred by our institutions emergency department for unenhanced helical CT scans. We reviewed the original radiographic report for each patient and recorded the size and location of ureteral calculi and other concurrent urinary tract calculi, if any. We also recorded the presence or absence of hydronephrosis, hydroureter, perinephric edema, and periureteral edema. A total of 49 patients had ureteral calculi, 17 patients had only renal calculi, and 34 patients had no stones. Forty-nine patients had ureteral calculi, and 40 (82%) of these 49 patients had associated CT signs including hydroureter and periureteral edema. Calculi were present in the proximal ureter in 11 patients, the midureter in seven patients, and the distal ureter including ureterovesical junction in 31 patients. Calculi were seen elsewhere in the urinary tract and renal pelvis in 44 patients. Other diagnostic tests and stone passage were used to confirm the CT diagnosis of ureteral stones. The sensitivity and specificity of helical CT in evaluating ureteral calculi were 100% and 94%, respectively. Sixteen extraurinary lesions were detected in 34 patients who had no urinary calculi. Most extraurinary lesions (81%) were deemed the cause of acute flank pain. The room time for CT averaged 26 min, compared to 69 min for intravenous urography (IVU). The charge for CT was

Assessment of rectal tumor infiltration utilizing endorectal MR imaging and comparison with endoscopic rectal sonography

600 compared to

Microwave Ablation of Renal Parenchymal Tumors Before Nephrectomy: Phase I Study

400 for IVU in our institution. Unenhanced helical CT was fast and accurate in determining the cause of colic and proved to be highly accurate for emergency situations.

CT-Guided Biopsy for the Diagnosis of Renal Tumors Before Treatment with Percutaneous Ablation

The preoperative assessment of depth of invasion of rectal carcinoma is increasingly important as new treatment methodologies are developed. Accuracy of preoperative endorectal MR imaging was therefore compared with that of the endoscopic rectal sonography in determining depth of invasion of rectal carcinomas.

Imaging approach to staging of renal cell carcinoma.

OBJECTIVE The purpose of this study was to determine, in renal neoplasms, the size of ablation zones induced in vivo with percutaneous microwave probes and whether skip areas remain within the ablation zones. CONCLUSION For a single 10-minute ablation, ablated volumes averaged 27 cm3 and 105 cm3 with a single-probe and a three-probe ablation array, respectively. There were no skip areas within the ablated zone. Microwave ablation can safely and quickly generate large ablation lesions and renal neoplasms.

RADIO FREQUENCY ABLATION OF LUNG METASTASES FROM RENAL CELL CARCINOMA

OBJECTIVE Percutaneous thermal ablation is an emerging technique in the management of renal cell carcinoma (RCC), with greatest efficacy in tumors < or = 3 cm. The purpose of this retrospective study was to evaluate the role and utility of pretreatment CT-guided biopsy in patients referred for percutaneous thermal ablation of renal tumors. CONCLUSION Less than 5% of samples in our study were benign, and 11.8% were nondiagnostic. Biopsy in smaller lesions was less accurate; therefore biopsy is less useful for these renal lesions. Because fine-needle aspiration (FNA) has higher sensitivity than core biopsy, an appropriate algorithm may be to begin with FNA and reserve core biopsy for cases in which an onsite cytotechnologist is unavailable or deems the sample of inadequate cellularity.