Percutaneous radiofrequency ablation of sporadic Bosniak III or IV lesions: treatment techniques and short-term outcomes

The safety and efficacy of laparoscopic microwave ablation-assisted partial nephrectomy: a new avenue for the treatment of cystic renal tumors

PURPOSE

Clinically, the management of cystic renal masses is tricky. The study aims to evaluate the safety and efficacy of laparoscopic microwave ablation-assisted partial nephrectomy (LMAPN) for cystic renal tumors.

METHODS AND MATERIALS

Between November 2017 and January 2022, LMAPN was performed on 43 patients (29 men and 14 women; age range: 22-80 years; median age 54 years) with Bosniak category III (n = 15) or IV (n = 28) cystic renal tumors (size range: 1.2-5.0 cm; mean size 2.8 cm). The median follow-up period was 26 months (range: 7-56 months). Baseline and perioperative data, pathological features, renal function, postoperative complications and oncologic outcomes were collected and evaluated.

RESULTS

Forty-three cystic renal tumors were successfully managed by LMAPN. The mean operating time was 79 min (range: 40-130 min). The mean time of renal pedicle clamping was 19 min (range: 12-25 min). Mean intraoperative blood loss was 28.4 mL (range: 10-80 mL). The mean postoperative hospitalization duration was 4 days (range: 2-6 days). Negative surgical margins were diagnosed in all cases. During the follow-up, no patient appeared with distant metastasis, wound or peritoneal cavity implantation. No major but minor complications of Clavien-Dindo grade I were encountered after the operation. The 1-, 3- and 4-year overall survival rate was 100%, 96.6% and 88.5%, respectively.

CONCLUSION

This is the first study focusing on LMAPN for cystic renal tumors, demonstrating its favorable feasibility, safety and disease control. Long-term follow-up is necessary to draw conclusions on the preference and advantages of the new therapeutic approach.

Asian Conference on Tumor Ablation guidelines for renal cell carcinoma

Thermal ablation has been established as an alternative treatment for renal cell carcinoma (RCC) in patients who are poor candidates for surgery. However, while American and European guidelines have been established for American and European patients, respectively, no ablation guidelines for Asian patients with RCCs have been established many years after the Asian Conference on Tumor Ablation (ACTA) had been held. Given that Western guidelines are difficult to apply to Asian patients due to differences in body habitus, economic status, and insurance systems, the current review sought to establish the first version of the ACTA guidelines for treating a RCC with thermal ablation.

Update on MRI of Cystic Renal Masses Including Bosniak Version 2019

Incidental cystic renal masses are common, usually benign, and almost always indolent. Since 1986, the Bosniak classification has been used to express the risk of malignancy in a cystic renal mass detected at imaging. Historically, magnetic resonance imaging (MRI) was not included in that classification. The proposed Bosniak v.2019 update has formally incorporated MRI, included definitions of imaging terms designed to improve interobserver agreement and specificity for malignancy, and incorporated a variety of masses that were incompletely defined or not included in the original classification. For example, at unenhanced MRI, homogeneous masses markedly hyperintense at T₂ -weighted imaging (similar to cerebrospinal fluid) and homogeneous masses markedly hyperintense at fat suppressed T₁ -weighted imaging (approximately ≥2.5 times more intense than adjacent renal parenchyma) are classified as Bosniak II and may be safely ignored, even when they have not been imaged with a complete renal mass MRI protocol. MRI has specific advantages and is recommended to evaluate masses that at computed tomography (CT) 1) have abundant thick or nodular calcifications; 2) are homogeneous, hyperattenuating, ≥3 cm, and nonenhancing; or 3) are heterogeneous and nonenhancing. Although MRI is generally excellent for characterizing cystic renal masses, there are unique weaknesses of MRI that bear consideration. These details and others related to MRI of cystic renal masses are described in this review, with an emphasis on Bosniak v.2019. A website (https://bosniak-calculator.herokuapp.com/) and mobile phone apps named "Bosniak Calculator" have been developed for ease of assignment of Bosniak classes. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

Comparison of General Anesthesia and Conscious Sedation during Computed Tomography–Guided Radiofrequency Ablation of T1a Renal Cell Carcinoma

Purpose

Percutaneous radiofrequency ablation is so painful that this treatment requires pain control such as conscious sedation or general anesthesia. It is still unclear which type of anesthesia is better for treatment outcomes of renal cell carcinoma. This study aimed to compare general anesthesia and conscious sedation in treating patients with renal cell carcinoma with radiofrequency ablation.

Methods

Between 2010 and 2015, 51 patients with biopsy-proven renal cell carcinomas (<4 cm) were treated with computed tomography–guided radiofrequency ablation. General anesthesia was performed in 41 and conscious sedation was performed in 10 patients. Tumour size, local tumour progression, metastasis, major complication, effective dose, glomerular filtration rate difference, and recurrence-free survival rate were compared between these groups.

Results

The mean tumour size was 2.1 cm in both groups ( P = .673). Local tumour progression occurred in 0% (0 of 41) of the general anesthesia group, but in 40% (4 of 10) of the conscious sedation group ( P = .001). Metastases in these groups occurred in 2.4% (1 of 41) of the general anesthesia group and 20% (2 of 10) of the conscious sedation group ( P = .094). No major complications developed in either group after the first radiofrequency ablation session. The mean effective doses in these groups were 21.7 mSv and 21.2 mSv, respectively ( P = .868). The mean glomerular filtration rate differences in the general anesthesia and conscious sedation groups were −13.5 mL/min/1.73 m2 and −19.1 mL/min/1.73 m2, respectively ( P = .575). Three-year recurrence-free survival rates in these groups were 97.6% and 60.0%, respectively ( P = .001).

Conclusions

General anesthesia may provide better intermediate outcomes than conscious sedation in treating small renal cell carcinomas with radiofrequency ablation.

Management of Urinoma Formation After Laparoscopic Cryoablation of Renal Cyst

Aim: To describe the presentation and management of a urinoma developing as a complication of laparoscopic cryoablation of a Bosniak III renal cyst.

Case: A 74-year-old woman presented with acute onset of severe left lower abdominal pain 1 day after a laparoscopic cryoablation of a 3 cm multilobular left cystic renal mass. CT revealed a perinephric fluid collection adjacent to the lower pole of the left kidney with active urinary extravasation seen on retrograde pyelogram, confirming the presence of an urinoma. A retrograde ureteral stent was placed with complete resolution of symptoms and the patient was discharged on the first postoperative day. Follow-up CT scans 2 weeks and 2 months after the procedure showed significant reduction of urinoma size, and retrograde pyelogram 5 months after showed resolution of urinoma.

Conclusion: Although often discussed as a possible complication, to our knowledge there are no published case reports in the literature regarding the formation of a urinoma after laparoscopic cryoablation. Furthermore, no data exist on the management of a urinoma after laparoscopic cryoablation. We propose that ureteral stenting is a reasonable approach to the management of this condition.

CT-Guided Radiofrequency Ablation of T1a Renal Cell Carcinoma in Korea: Mid-Term Outcomes

Objective

To evaluate the mid-term outcomes of percutaneous radiofrequency ablation (RFA) treatment in patients with small (< 4 cm) renal cell carcinoma (RCC) in Korea.

Materials and Methods

Between 2010 and 2015, 51 patients (40 men and 11 women; median age, 57 years) with biopsyproven 51 RCC were treated using CT-guided RFA. All patients were clinically staged T1aN0M0 prior to RFA. The median tumor size and follow-up period were 2.1 cm (range, 1.0–3.9 cm) and 26 months (4–60 months), respectively. Local tumor progression, distant metastasis, primary and secondary effectiveness rates, and major complication rates were recorded. Estimated glomerular filtration rates (GFRs) between pre-RFA and last follow-up were compared using paired t tests. The 2-year recurrence-free survival rate was calculated using Kaplan-Meier survival analysis.

Results

Of the 51 patients, 2 (3.9%) experienced local tumor progression, and 1 (2.0%) had lymph node metastasis after the first RFA session. Primary and secondary effectiveness rates were 96.1% (49/51) and 100% (1/1), respectively. Only 1 patient experienced a major complication (uretero-pelvic stricture) after the second RFA session for treating a local tumor progression, and the major complication rate was 1.9% (1/52). The median pre-RFA and last follow-up GFRs were 87.1 mL/ min/1.73 m² (14.2–142.7 mL/min/1.73 m²) and 72.0 mL/min/1.73 m² (7.2–112.6 mL/min/1.73 m²), respectively (p < 0.0001). The 2-year recurrence-free survival rate was 96.0%.

Conclusion

CT-guided RFA is a safe and effective treatment in Korean patients with T1a RCC because of excellent mid-term outcomes.