Percutaneous microwave ablation therapy of renal cancer local relapse after radical nephrectomy: a feasibility and efficacy study

Imaging Recommendations for Diagnosis, Staging, and Management of Renal Tumors

Renal cell carcinomas accounts for 2% of all the cancers globally. Most of the renal tumors are detected incidentally. Ultrasound remains the main screening modality to evaluate the renal masses. A multi -phase contrast enhanced computer tomography is must for characterizing the renal lesions. Imaging plays an important role in staging, treatment planning and follow up of renal cancers. In this review , we discuss the imaging guidelines for the management of renal tumors.

Cone Beam Computed Tomography Image Fusion with Cross Sectional Images for Percutaneous Renal Tumor Ablation: Preliminary Data

PURPOSE

Percutaneous ablative treatments in the kidney are now standard options for local cancer therapy. Multimodality image guidance, combining two 3D image sets, may improve procedural images and interventional strategies. We aimed to assess the value of intra-procedural cone beam computed tomography (CBCT) with magnetic resonance (MR) or CT imaging fusion technique in the guidance of percutaneous microwave ablation (MWA) of renal neoplasms.

MATERIALS AND METHODS

Fifteen patients (eight males, seven females, median age 65 years, median lesion size 20 mm) underwent percutaneous MWA for 15 renal tumors. All the procedures were performed in a dedicated angiography room setting; CBCT ablation planning capabilities included multimodality image fusion. Preoperative contrast-enhanced CT was available in 12 patients, whereas magnetic resonance imaging in the remaining. All patients were considered inoperable due to comorbidities, advanced age, and/or refusal to undergo surgery. Exclusion criteria were: tumors visible at unenhanced CBCT, metastatic disease, and uncorrected coagulopathy. Technical success and technical effectiveness were calculated. Procedural time, complications and recurrences were registered.

RESULTS

MWA under CBCT-guidance with fusion technique was technically successful in 14 out of 15 cases (93%). The median procedural time was 45 min. No procedure-related complications were reported. No enhancing tissue was visualized in the area of ablation at 1-month follow-up. All 15 cases were recurrence-free at last follow-up assessment (median follow-up of 12 months); no cancer-specific deaths were registered.

CONCLUSION

CBCT-CT/MR image fusion is technically feasible and safe in achieving correct targeting and complete ablation of renal lesions. This approach bears the potential to overcome most of the limitations of unenhanced CBCT guidance alone; larger series are needed to validate this technique.

Efficacy and safety of CT-guided microwave ablation for stage T1a renal cell carcinoma in patients with a solitary kidney

OBJECTIVE

To retrospectively evaluate early clinical outcomes of percutaneous microwave ablation (MWA) for stage T1a renal cell carcinomas (RCCs) in solitary kidney patients.

MATERIALS AND METHODS

15 solitary kidney patients with 16 stage T1a N0M0 biopsy-proved RCCs underwent CT-guided percutaneous microwave ablation between October 2016 and July 2020. The patients were followed up with contrast-enhanced computed tomography or magnetic resonance imaging at 1, 3, and 6 months and every 6 months thereafter. Serum creatinine levels of each patient pre MWA, 1 day after MWA and the most recent record were collected. Technical effectiveness, local recurrence, survival rates and complications were accessed.

RESULTS

Complete ablation was achieved in all 16 tumors (100%) including 13 clear cell carcinomas and 3 papillary carcinomas. Within the follow-up time (median: 24 months) no tumor recurrence or major complication was detected. No significant change in serum creatinine level was noted. The cancer-specific survival rate was 100% (15 of 15), and 1-, 2-, and 3-year overall survival rates were 100%, 93.3%, and 93.3%, respectively.

CONCLUSION

Percutaneous MWA is an effective and safe treatment option for stage T1a RCCs in solitary kidney patients; it can achieve high complete ablation rate in selected lesions of appropriate size and location.

Long-Term Follow-Up Outcomes after Percutaneous US/CT-Guided Radiofrequency Ablation for cT1a-b Renal Masses: Experience from Single High-Volume Referral Center

Image-guided thermal ablations are increasingly applied in the treatment of renal cancers, under the guidance of ultrasound (US) or computed tomography (CT). Sometimes, multiple ablations are needed. The aim of the present study was to evaluate the long-term results in patients with renal mass treated with radiofrequency ablation (RFA) with both US and CT, with a focus on the multiple ablations rate. 149 patients (median age 67 years) underwent RFA from January 2008 to June 2015. Median tumor diameter was 25 mm (IQR 17–32 mm). Median follow-up was 54 months (IQR 44–68). 27 (18.1%) patients received multiple successful ablations, due to incomplete ablation (10 patients), local tumor progression (8 patients), distant tumor progression (4 patients) or multiple tumor foci (5 patients), with a primary and secondary technical efficacy of 100%. Complications occurred in 13 (8.7%) patients (6 grade A, 5 grade C, 2 grade D). 24 patients died during follow-up, all for causes unrelated to renal cancer. In conclusion, thermal ablations with the guidance of US and CT are safe and effective in the treatment of renal tumors in the long-term period, with a low rate of patients requiring multiple treatments over the course of their disease.