Scott M. Castle

Initial Experience Using Microwave Ablation Therapy for Renal Tumor Treatment: 18-Month Follow-up

OBJECTIVES To assess efficacy and morbidity of microwave ablation (MWA) for small renal tumors in an initial cohort of patients. MWA is a recently introduced thermal needle ablation treatment modality with theoretical advantages compared with radiofrequency ablation, such as greater intratumoral temperatures, lack of a grounding pad, and superior convection profile. However, experience has been limited in the human kidney. METHODS Ten patients with a single, solid-enhancing renal tumor from June 2008 to November 2008 received laparoscopic or computed tomography-guided percutaneous MWA at a tertiary referral center with ≥14 months of follow-up. MWA was performed using the Valleylab Evident, 915-MHz MWA system at 45 W with intraoperative biopsy before ablation, and peripheral fiberoptic thermometry to determine the treatment endpoints. The patients were followed up with contrast-enhanced computed tomography at 1 month, 6 months to 1 year, and annually to monitor for tumor recurrence. RESULTS The follow-up duration for the 6 male and 4 female patients (mean tumor size 3.65 cm, range 2.0-5.5; mean age 69.8 years) was 17.9 months. The recurrence rate, defined by persistent enhancement, was 38% (3 of 8). The intraoperative and postoperative complication rate was 20% and 40%, respectively. CONCLUSIONS MWA resulted in poor oncologic outcomes with a significant complication rate at an intermediate level of follow-up. However, MWA has promising theoretical advantages and should not be discarded. Additional studies should be considered to better understand the microwave-tissue interaction and treatment endpoints for different size renal masses before widespread use.

Radiofrequency ablation (RFA) therapy for renal angiomyolipoma (AML): an alternative to angio‐embolization and nephron‐sparing surgery

Study Type – Therapy (case series)

Cost comparison of nephron-sparing treatments for cT1a renal masses

OBJECTIVES Treatment options for small renal tumors have evolved from radical nephrectomy (RN) to partial nephrectomy (PN), thermal ablation, or active surveillance. With the advancement of techniques, costs differences are unclear. The objective of this study is to compare the 6-month costs associated with nephron-sparing procedures for cT1a renal tumors. MATERIALS AND METHODS We performed a review of patients diagnosed with a solitary cT1a renal mass who underwent surgical treatment from June 2008 to May 2011. Open partial nephrectomy (OPN), robot-assisted partial nephrectomy (RLPN), laparoscopic radio-frequency ablation (LRFA), or computed tomography guided radio frequency ablation (CTRFA) was performed on 173 patients. Cost data were collected for surgical costs, associated hospital stay, and the 6-month postoperative period. RESULTS Patients underwent surgery, including 52 OPN, 48 RLPN, 44 LRFA, and 29 CTRFA. Median total costs associated were

Low biopsy volume in ureteroscopy does not affect tumor biopsy grading in upper tract urothelial carcinoma

17,018,

Comparison of Safety, Renal Function Outcomes and Efficacy of Laparoscopic and Percutaneous Radio Frequency Ablation of Renal Masses

20,314,

Radiofrequency ablation for treatment of renal tumors: technological principles and outcomes

13,965, and

Laparoscopic and Image-guided Radiofrequency Ablation of Renal Tumors: Patient Selection and Outcomes

6,475, for OPN, RLPN, LRFA, and CTRFA, respectively. When stratified by approach differences were noted for total cost (P < 0.001), operating room (OR) time (P < 0.001), surgical supply (P < 0.001), and room and board (P < 0.001) in univariable analysis. Multivariable linear regression (R(2) = 0.966) showed surgical approach (P = 0.007), length of stay (P < 0.001), and OR time (P < 0.001) to be significant predictors of total cost. However, tumor size (P = 0.175), and Charlson comorbidity index (P = 0.078) were not statistically significant. CONCLUSIONS Six-month cost of nephron-sparing surgery is lowest with radio frequency ablation (RFA) by either laparoscopic or computed tomography (CT)-guided approach compared to RLPN and OPN. As oncologic and safety outcomes improve and become comparable in all nephron-sparing surgery (NSS) approaches, cost of each procedure will start to play a stronger role in the clinical and healthcare policy setting.

Laparoendoscopic single site nephrectomy with the SPIDER surgical system: Engineering advancements tested in a porcine model

OBJECTIVES Urothelial carcinomas (UC) from the upper urinary tract represent 7%-10% of all kidney malignancies. With current ureteroscopic (URS) techniques, small tissue samples are usually the only available histopathologic material for evaluation, representing a diagnostic challenge. Precision in diagnosis is essential for treatment decision making. There has been much debate as to whether tumor grade and stage found on biopsy agree with final pathology. The purpose of this study is to evaluate whether URS biopsy volume affects tumor grading and staging agreement between biopsy and nephroureterectomy (NU) specimens. MATERIALS AND METHODS We reviewed 137 URS biopsies in 81 patients with suspected upper urinary tract UC performed from April 2002 to April 2011. Of those, 54 patients had both the URS biopsy and NU performed at our institution and were available for review. Biopsy dimensions were recorded to calculate estimated ellipsoid volume, and 2 urological pathologists independently evaluated histologic grade (ISUP/WHO 2004), (based on pleomorphism and mitosis) and depth of invasion. Statistical analysis was performed to evaluate URS biopsy and NU specimen grade and stage concordance. In addition, univariable and multivariable analyses was performed to assess the effect of biopsy volume on agreement. RESULTS Of the 54 patients studied, low grade and high grade UC biopsy were found in 8 (15%) and 46 (85%), URS biopsies, respectively. Regarding biopsy stage, 51 (94%), 1 (2%), and 2 (4%) were stage Ta, T1, T2, respectively. Grade concordance was 92.6%, (95% CI: 82.4%-98.0%). Stage concordance was 43% (95% CI: 28.7%-55.9%). Multivariable analysis showed biopsy volume did not affect tumor assessment of grade (P = 0.81) or stage (P = 0.44). CONCLUSIONS Histologic grade assigned on the URS biopsy sample accurately predicts histologic grade in the resected specimen (92.6%), even when the biopsy volume is small. Grading in URS biopsies provides sufficient information for clinical decision making that is independent of sample volume.

Initial experience with laparoendoscopic single-site simple nephrectomy using the TransEnterix SPIDER surgical system: assessing feasibility and safety.

PURPOSE With the increased incidence of low stage renal cancers, thermal ablation technology has emerged as a viable treatment option. Current AUA (American Urological Association) guidelines include thermal ablation as a treatment modality for select individuals. We compared the laparoscopic and percutaneous approach for the radio frequency ablation of renal tumors under the guidance of urological surgeons. MATERIALS AND METHODS We reviewed our radio frequency ablation database of patients with renal masses undergoing laparoscopic or computerized tomography guided percutaneous radio frequency ablation with simultaneous peripheral fiberoptic thermometry from November 2001 to January 2011 at a single tertiary care center. Data were collected on patient demographics, and surgical and clinicopathological outcomes stratified by approach. RESULTS A total of 298 patients with 316 renal tumors underwent laparoscopic (122 tumors) or computerized tomography guided (194 tumors) radio frequency ablation. There were no statistically significant differences between the laparoscopic and computerized tomography guided radio frequency ablation groups with respect to patient demographics, complication rates and renal functional outcomes (p>0.05). The 3-year Kaplan-Meier estimation of radiographic recurrence-free probability was 95% for computerized tomography guided radio frequency ablation and 94% for laparoscopic radio frequency ablation (p=0.84). Subanalysis of the 212 (67%) renal cell carcinoma tumors showed a 3-year Kaplan-Meier estimation of oncologic recurrence-free probability (post-ablation biopsy proven viable tumor) of 94% for computerized tomography guided radio frequency ablation and 100% for laparoscopic radio frequency ablation (p=0.16). Median followup was 21 months for laparoscopic radio frequency ablation) and 19 months for computerized tomography guided radio frequency ablation. CONCLUSIONS Laparoscopic and computerized tomography guided radio frequency ablation appear safe and effective with statistically equivalent rates of complications and recurrence.

Intravesical Methylene Blue Facilitates Precise Identification of the Diverticular Neck During Robot-Assisted Laparoscopic Bladder Diverticulectomy

Radiofrequency ablation (RFA) is a minimally invasive, energy-based, needle-ablative treatment modality that is currently being used to treat small renal masses (SRMs) and offers advantages over extirpative techniques. RFA treats SRM with heat induced by the tissue impedance to radiofrequency current emitted from a needle probe within the SRM. Currently available RFA systems use either an impedance- or temperature-based treatment algorithm to reach treatment end point while minimizing risk of carbonization. Physical limitations, such as electrical property heterogeneity and convective heat loss due to blood flow, and technical considerations should be addressed when performing RFA. Nonetheless, investigations with intermediate follow-up have demonstrated single-treatment radiographic recurrence-free rates of >90%. Future trends include the use of noninvasive imaging thermometry, electromagnetic targeting and adjuvant techniques.