John R. Kachura

Active Surveillance of Small Renal Masses: Progression Patterns of Early Stage Kidney Cancer ☆

BACKGROUND Most early stage kidney cancers are renal cell carcinomas (RCCs), and most are diagnosed incidentally by imaging as small renal masses (SRMs). Indirect evidence suggests that most small RCCs grow slowly and rarely metastasize. OBJECTIVE To determine the progression and growth rates for newly diagnosed SRMs stratified by needle core biopsy pathology. DESIGN, SETTING, AND PARTICIPANTS A multicenter prospective phase 2 clinical trial of active surveillance of 209 SRMs in 178 elderly and/or infirm patients was conducted from 2004 until 2009 with treatment delayed until progression. INTERVENTION Patients underwent serial imaging and needle core biopsies. MEASUREMENTS We measured rates of change in tumor diameter (growth measured by imaging) and progression to ≥ 4 cm, doubling of tumor volume, or metastasis with histology on biopsy. RESULTS AND LIMITATIONS Local progression occurred in 25 patients (12%), plus 2 progressed with metastases (1.1%). Of the 178 subjects with 209 SRMs, 127 with 151 SRMs had>12 mo of follow-up with two or more images, with a mean follow-up of 28 mo. Their tumor diameters increased by an average of 0.13 cm/yr. Needle core biopsy in 101 SRMs demonstrated that the presence of RCC did not significantly change growth rate. Limitations included no central review of imaging and pathology and a short follow-up. CONCLUSIONS This is the first SRM active surveillance study to correlate growth with histology prospectively. In the first 2 yr, the rate of local progression to higher stage is low, and metastases are rare. SRMs appear to grow very slowly, even if biopsy proven to be RCC. Many patients with SRMs can therefore be initially managed conservatively with serial imaging, avoiding the morbidity of surgical or ablative treatment.

Günther Tulip Retrievable Vena Cava Filter: Results from the Registry of the Canadian Interventional Radiology Association

PURPOSE To report data collected by the Canadian Registry of the Günther Tulip Retrievable Filter (GTF). MATERIALS AND METHODS Between February 1998 and December 2000, 90 patients at eight hospitals underwent implantation of 91 GTFs. There were 45 male patients and 45 female patients, age 17-88 years, with a mean age of 49 years. Indications for filter placement were pulmonary embolism (PE) or deep vein thrombosis (DVT) with a contraindication to anticoagulation in 83 patients, prophylaxis after massive PE in one, prophylaxis for proximal free-floating thrombus in one, and prophylaxis with no DVT or PE in six patients (major trauma, n = 4; high preoperative risk, n = 2). GTF retrieval was attempted in selected patients from a right internal jugular vein approach. RESULTS One GTF was inadvertently placed in the right iliac vein and could not be retrieved. There were no other major placement complications. GTF retrieval was attempted in 52 patients (53 GTFs); 52 GTFs were successfully retrieved from 51 patients. Implantation times were 2-25 days (mean, 9 d). Of these 51 patients, 37 underwent follow-up for 5-420 days (mean, 103 d) after filter retrieval. Four patients (8% of retrieved GTFs) required reinsertion of a permanent filter 17-167 days (mean, 78 d) after GTF retrieval as a result of bleeding from anticoagulation (n = 2) or because the patient required further surgery (n = 2). One other patient had recurrent DVT 230 days after retrieval; no PE or other complication was documented in the retrieval group. GTFs were not retrieved from 39 patients for various reasons. Of these 39 patients, 25 underwent follow-up 7-420 days (mean, 85 d) after filter placement. Two patients developed filter occlusion (5%); no other complications were documented. CONCLUSION The GTF has a broad range of utility: it can be used as a permanent filter or retrieved after implantation periods of 15 days and possibly longer. However, indications for retrieval require further study, as does the maximum implantation time.

Outcomes of Small Renal Mass Needle Core Biopsy, Nondiagnostic Percutaneous Biopsy, and the Role of Repeat Biopsy

BACKGROUND Percutaneous needle core biopsy has become established in the management of small renal masses ≤ 4 cm (SRMs). Recent series have reported success rates of ≥ 80%. Nondiagnostic results continue to be problematic. OBJECTIVE To determine the results of SRM biopsy and the outcomes of nondiagnostic biopsy and repeat biopsy. DESIGN, SETTING, AND PARTICIPANTS Patients undergoing renal tumor biopsy (RTB) for suspected renal cell carcinoma (RCC) were included in a prospectively maintained database. MEASUREMENTS The database was analyzed retrospectively to determine the pathology and outcomes of SRM biopsy. Outcomes of patients with nondiagnostic biopsy were determined. Patients undergoing repeat biopsy were identified and their outcomes analyzed. RESULTS AND LIMITATIONS Three hundred forty-five biopsies were performed (mean diameter: 2.5 cm). Biopsy was diagnostic in 278 cases (80.6%) and nondiagnostic in 67 cases (19.4%). Among diagnostic biopsies, 221 (79.4%) were malignant, 94.1% of which were RCC. Histologic subtyping and grading of RCC was possible in 88.0% and 63.5% of cases, respectively. Repeat biopsy was performed in 12 of the 67 nondiagnostic cases, and a diagnosis was possible in 10 (83.3%). Eight lesions were malignant and two were oncocytic neoplasms. Pathology was available for 15 masses after initial nondiagnostic biopsy; 11 (73%) were malignant. Larger tumor size and a solid nature on imaging predicted a successful biopsy on multivariate analysis. Grade 1 complications were experienced in 10.1% of cases, with no major bleeding and no seeding of the biopsy tract. There was one grade 3a complication (0.3%). This is a retrospective study and some data are unavailable on factors that may affect biopsy success rates. Repeat biopsy was not standard practice prior to this analysis. CONCLUSIONS RTB can be performed safely and accurately in the investigation of renal masses ≤ 4 cm. A nondiagnostic biopsy should not be considered a surrogate for the absence of malignancy. Repeat biopsy can be performed with similar accuracy, providing a diagnosis for most patients.

The Uncertainty Of Radio Frequency Treatment Of Renal Cell Carcinoma: Findings At Immediate And Delayed Nephrectomy

PURPOSE Radio frequency thermal therapy for the ablation of renal cell carcinoma has been reported. Outcomes are usually measured by imaging alone. We have performed ex vivo and in vivo experiments using radio frequency in porcine models in our laboratory. We now report our early experience in the treatment of renal cell carcinoma in patients who underwent post-radio frequency radical or partial nephrectomy. MATERIALS AND METHODS We treated 10 patients diagnosed with small renal masses with radio frequency. All masses were biopsied before treatment. In 4 patients 5 renal cell carcinomas were treated with radio frequency after surgical exposure of the tumor followed immediately by partial or radical nephrectomy (acute group). Six other patients were treated percutaneously with ultrasound or computerized tomography guided radio frequency under local anesthesia and intravenous sedation 7 days before partial or radical nephrectomy (delayed group). A median of 2 radio frequency cycles was applied. Mean total heating time was 17 minutes 15 seconds. Specimens were analyzed grossly and histologically. Triphasic contrast-enhanced computerized tomography and/or magnetic resonance imaging was performed before and 7 days after radio frequency treatment in the delayed group. RESULTS Mean radiological largest diameter of all 11 masses was 2.4 cm. and mean gross diameter was 2.2 cm. Pathological examination demonstrated residual viable tumor in approximately 5% of the volume in 4 of the 5 tumors in the acute group and in 3 of the 6 masses of the delayed group. In 1 delayed case the viable tumor appeared to be in contact with the renal vein. No significant complications were observed in 9 of the 10 patients. In 1 delayed case, a subcapsular hepatic hematoma, biliary fistula and pneumonia developed and resolved. CONCLUSIONS Based on our experience, we continue to consider percutaneous radio frequency for the treatment of small renal cell carcinomas as a potentially curative therapy. However, complete tumor cell death appears to be difficult to achieve with our current treatment protocol. More phase II testing is indicated to ensure that this technique is an effective and reproducible treatment alternative.

Contemporary Results of Percutaneous Biopsy of 100 Small Renal Masses: A Single Center Experience

PURPOSE Percutaneous biopsy of small renal tumors has not been historically performed because of concern about complications and accuracy. We reviewed our experience with percutaneous needle biopsy of small renal masses to assess the safety and accuracy of the procedure, the potential predictors of a diagnostic result and the role of biopsy in clinical decision making. MATERIALS AND METHODS A total of 100 percutaneous needle biopsies of renal masses less than 4 cm were performed between January 2000 and May 2007 with 18 gauge needles and a coaxial technique under ultrasound and/or computerized tomography guidance. A retrospective chart review was performed to document the complication rate and the ability to obtain sufficient tissue for diagnosis. Tumor size, tumor type (solid vs cystic), image guidance, biopsy number and core length were assessed for the ability to predict a diagnostic biopsy. RESULTS No tumor seeding or significant bleeding was observed. Of the core biopsies 84 (84%) were diagnostic for a malignant (66) or a benign (18) tumor. Larger tumor size and a solid pattern were significant predictors of a diagnostic result. Histological subtyping and grading were possible on core biopsies in 93% and 68% of renal cell carcinomas, respectively. A total of 20 patients underwent surgery after a diagnostic biopsy. The histological concordance of biopsies and surgical specimens was 100%. CONCLUSIONS Percutaneous needle biopsy of renal masses less than 4 cm is safe and provides adequate tissue for diagnosis in most cases. Larger tumor size and a solid pattern are significant predictors of a successful biopsy. Renal tumor biopsy decreases the rate of unnecessary surgery for benign tumors and can assist the clinician with treatment decision making, especially in elderly and unfit patients.

Needle Tract Seeding after Radiofrequency Ablation of Hepatic Tumors

PURPOSE To determine the incidence and risk factors associated with needle tract seeding after radiofrequency ablation (RFA) of liver tumors. MATERIALS AND METHODS A prospective data base of patients with hepatic tumors treated by RFA from December 1999 until August 2003 was reviewed to identify patients with needle tract seeding. During this period, 200 patients (148 men, 52 women) with 299 lesions underwent 298 treatment sessions. Patients with both primary (153 hepatocellular carcinoma, two cholangiocarcinoma) and a variety of secondary tumors (35 colorectal, 10 other) were treated. RFA was performed percutaneously with computed tomography (CT) and/or ultrasound (US) guidance, or with US guidance at laparoscopy or laparotomy. All procedures were performed with a LeVeen needle electrode. The needle tract was not routinely coagulated or embolized. RESULTS Eight patients out of 200 (4%) were identified with needle tract seeding, based on imaging findings or surgical reintervention. This corresponds to a rate of eight of 298 (2.7%) per treatment session and eight of 299 (2.7%) per lesion. Statistically significant risk factors for neoplastic seeding included treatment of a subcapsular lesion (OR = 11.57, P = .007), multiple treatment sessions (OR = 2.0, P = .037), and multiple electrode placements (OR = 1.4, P = .006). CONCLUSIONS Neoplastic seeding may occur after RFA of liver tumors. The results show that the frequency of this complication is not insignificant, and are at the upper end of rates reported in the literature of 0.5% to 2.8%. Specific risk factors identified in this study include treatment of subcapsular lesions, patients treated in multiple sessions, and lesions requiring more than one electrode placement.

Renal Tumor Biopsy for Small Renal Masses: A Single-center 13-year Experience

BACKGROUND Renal tumor biopsy (RTB) for the characterization of small renal masses (SRMs) has not been widely adopted despite reported safety and accuracy. Without pretreatment biopsy, patients with benign tumors are frequently overtreated. OBJECTIVE To assess the diagnostic rate of RTBs, to determine their concordance with surgical pathology, and to assess their impact on management. DESIGN, SETTING, AND PARTICIPANTS This is a single-institution retrospective study of 529 patients with biopsied solid SRMs ≤4 cm in diameter. RTBs were performed to aid in clinical management. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Diagnostic and concordance rates were presented using proportions. Factors that contributed to a diagnostic biopsy were identified using a multivariable logistic regression. RESULTS AND LIMITATIONS The first biopsy was diagnostic in 90% (n=476) of cases. Of the nondiagnostic biopsies, 24 patients underwent a second biopsy of which 83% were diagnostic. When both were combined, RTBs yielded an overall diagnostic rate of 94%. Following RTB, treatment could have been avoided in at least 26% of cases because the lesion was benign. Tumor size and exophytic location were significantly associated with biopsy outcome. RTB histology and nuclear grade were highly concordant with final pathology (93% and 94%, respectively). Adverse events were low (8.5%) and were all self-limited with the exception of one. Although excellent concordance between RTB and final pathology was observed, only a subset of patients underwent surgery following biopsy. Thus it is possible that some patients were misdiagnosed. CONCLUSIONS RTB of SRMs provided a high rate of diagnostic accuracy, and more than a quarter were benign. Routine RTB for SRMs informs treatment decisions and diminishes unnecessary intervention. Our results support its systematic use and suggest that a change in clinical paradigm should be considered. PATIENT SUMMARY Renal tumor biopsy (RTB) for pretreatment identification of the pathology of small renal masses (SRMs) is safe and reliable and decreases unnecessary treatment. Routine RTB should be considered in all patients with an indeterminate SRM for which treatment is being considered.

Tolerance, hospital stay, and recovery after uterine artery embolization for fibroids: The Ontario uterine fibroid embolization trial

PURPOSE Uterine artery embolization (UAE) is gaining popularity as an alternative to hysterectomy for the treatment of fibroids. Although minimally invasive treatments such as UAE offer the potential of fewer complications, shorter hospital stay, and quicker recovery than surgery, there have been few published data on tolerance and recovery in patients undergoing UAE. MATERIALS AND METHODS This was a multicenter prospective single-arm clinical treatment trial involving the practices of 11 interventional radiologists in eight Ontario university-affiliated and community hospitals. Between November 1998 and November 2000, 555 women underwent UAE for symptomatic uterine fibroids. Follow-up included ultrasound examinations and telephone interviews. UAE was performed under conscious sedation. Polyvinyl alcohol particles (355-500 micro m) were the primary embolic agent, and the procedural endpoint involved stasis in the uterine arteries. Pain protocols included antiinflammatory medications and narcotics and a planned overnight hospital admission. Tolerance and recovery were measured by patient-reported pain intensity (10-point numeric rating and five-point descriptor scale), hospital length of stay (LOS), and time until return to work. RESULTS Intraprocedural pain was reported by 30% of patients and postprocedural pain was reported by 92% of patients (mean pain rating +/- SD, 7.0 +/- 2.47). The mean hospital LOS was 1.3 nights. Postprocedural pain was the most common indication for an LOS greater than 1 night (18%) or 2 nights (5%). Return visits to the hospital (10%) and readmissions (3%) were primarily for pain. The overall postprocedural complication rate was 8.0% (95% CI: 5.9%-10.6%). Of the 44 complications, 32 (73%) were pain-related. The mean recovery time after UAE was 13.1 days (median, 10.0 d). CONCLUSION The majority of patients had a 1-night LOS after UAE and recovered within 2 weeks. Postprocedural pain varied considerably and was the major indication for extended hospital stay and recovery.

Percutaneous Management of Chronic Mesenteric Ischemia: Outcomes after Intervention

PURPOSE To assess the efficacy and durability of percutaneous transluminal angioplasty (PTA)/stent placement for treatment of chronic mesenteric ischemia (CMI). MATERIALS AND METHODS A retrospective review of patients treated from January 1986 to August 2003 was conducted. Twenty-nine patients (mean age, 62 years) were treated for clinical symptoms consistent with CMI. Clinical diagnosis was verified with angiographic assessment and PTA with or without stent placement was performed based on angiographic and/or pressure gradient findings. Outcomes were estimated with the Kaplan-Meier method. RESULTS A total of 63 interventions were performed in 29 patients during the study period. Of these 63 interventions, 46 PTA and 17 stent implantation procedures were performed. Thirty-four interventions were performed for SMA stenosis/occlusion, 17 interventions for celiac artery stenosis/occlusion, and four interventions were performed on aorto-mesenteric graft stenoses. Technical success was 97%, and clinical success (defined as clinical resolution of symptoms) was 90% (26 of 29 patients). Mean duration of follow-up was 28.3 months. Primary patency for all interventions at 3, 6, and 12 months was 82.7% (95% CI: 68.7-96.7), 78.9% (66.7-91.1), and 70.1% (55.1-85.6), respectively. Primary assisted patency for all interventions at 3, 6, and 12 months was 87.9% (79.0-95.3), 87.9% (79.2-95.1), and 87.9% (77.3-98.3), respectively. An average of 1.9 interventions per patient was required. One major complication occurred (3.4%). There were three minor complications (10.3%). CONCLUSIONS Percutaneous intervention for CMI is safe with durable early and midterm clinical success. However, repeated intervention is often required for improved primary assisted patency.

Technical results and effects of operator experience on uterine artery embolization for fibroids: the Ontario Uterine Fibroid Embolization Trial.

PURPOSE To document the technical results and spectrum of practice of uterine artery embolization (UAE) for fibroids in the health care setting in Canada. The effects of interventional radiologists (IRs) experience with UAE on procedure and fluoroscopy time were also investigated. MATERIALS AND METHODS The study involved a multicenter prospective single-arm clinical treatment trial and included the practices of 11 IRs at eight university-affiliated teaching and community hospitals. Vascular access with percutaneous femoral artery approach was followed by transcatheter delivery of polyvinyl alcohol (PVA) particles into uterine arteries with fluoroscopic guidance. Technical success, complications, procedural time, fluoroscopy time, and effects of operator experience were outcomes analyzed. RESULTS Between November 1998 and November 2000, 570 embolization procedures were performed in 555 patients. UAE was bilaterally successful in 97% (95% CI: 95%-98%). Variant anatomy was the most common reason for failure to embolize bilaterally. The procedural complication rate was 5.3% (95% CI: 3.6%-7.4%). Of the 30 events, three involved major complications (one seizure and two allergic reactions) that resulted in additional care or extended hospital stay. Procedure time and fluoroscopy time averaged 61 minutes (95% CI; 58-63 minutes) and 18.9 minutes (95% CI; 18-19.8) and varied significantly among IRs (P <.001; P <.001). The average 27% reduction in procedure time (20 minutes; P <.001) and 24% reduction in fluoroscopy time (5.1 minutes; P <.001) with increasing UAE experience were significant. CONCLUSIONS A high level of technical success with few complications was obtained with a variety of operators in diverse practice settings. Increased experience in UAE significantly reduced procedure and fluoroscopy time.