Background: The effect of microwave ablation (MWA) for the renal cell carcinoma (RCC) in Von Hippel-Lindau (VHL) disease is unclear.
Objective: To assess the safety, Technique efficacy, renal function and oncological outcome of MWA for RCC in VHL patients.
Methods: Consecutive patients with RCCs in VHL disease treated by MWA were retrospectively collected from November 2009 to October 2020. The technical efficacy rate and complications were assessed. The outcomes of pre- and post-ablative eGFR were compared. The local recurrent-free survival (LRFS), renal-cancer-free survival (RCFS), cancer-specific survival (CSS), overall survival (OS) and complications were presented.
Results: A total of 10 patients (mean age, 39.0 years ± 10.7 [SD]; 3 women) with 28 RCCs (mean tumor size, 3.0 cm ± 0.34; mean tumor volume, 20.7 mL ± 43.3) treated with MWA were included. Th median follow-up time was 52 months(IQR:27-80). The overall technical efficacy rate was 100% with no major complications occurred. No significant statistical difference between pre-ablative and postablative creatinine level (102.0 µmol/L ± 30.4 vs 112.3 µmol/L ± 38.7, p = 0.06), but the pre-ablative eGFR level was significantly higher than the post-ablative eGFR (78.0 mL/(min*1.73m2) ± 28.6 vs 72 mL/(min*1.73m2) ± 31.4, p = 0.04), with the mean decrease of 5.86 ml/(min*1.73m2). The local recurrent-free survival(LRFS) and renal-cancer-free survival (RCFS) were 100% and 60%, respectively. The cancer specifical survival (CSS) and overall survival (OS) were 95.5% and 100%, respectively.
Conclusion: Microwave ablation is a safe and feasible method for the treatment of RCC in VHL disease, preserving renal function and yielding satisfactory oncological outcomes.
Background: Despite the theoretical advantages of treating metastatic bone disease with microwave ablation (MWA), there are few reports characterizing microwave absorption and bioheat transfer in bone. This report describes a computational modeling-based approach to simulate directional microwave ablation (dMWA) in spine, supported by ex vivo and pilot in vivo experiments in porcine vertebral bodies.
Materials and methods: A 3D computational model of microwave ablation within porcine vertebral bodies was developed. Ex vivo porcine vertebra experiments using a dMWA applicator measured temperatures approximately 10.1 mm radially from the applicator in the direction of MW radiation (T1) and approximately 2.4 mm in the contra-lateral direction (T2). Histologic assessment of ablated ex vivo tissue was conducted and experimental results compared to simulations. Pilot in vivo experiments in porcine vertebral bodies assessed ablation zones histologically and with CT and MRI.
Results: Experimental T1 and T2 temperatures were within 3-7% and 11-33% of simulated temperature values. Visible ablation zones, as indicated by grayed tissue, were smaller than those typical in other soft tissues. Posthumous MRI images of in vivo ablations showed hyperintensity. In vivo experiments illustrated the technical feasibility of creating directional microwave ablation zones in porcine vertebral body.
Conclusion: Computational models and experimental studies illustrate the feasibility of controlled dMWA in bone tissue.
Purpose: The treatment of recurrent thyroid cancer with critical organ invasion is challenging. The combination of radiofrequency ablation (RFA) and external beam radiation therapy (EBRT) has been proposed as an effective option. This study evaluates outcomes for inoperable residual/recurrent differentiated thyroid cancer (rDTC) patients treated with RFA followed by EBRT.
Materials and methods: Patients with rDTC treated with RFA followed by EBRT were retrospectively studied. RFA was performed using a free-hand, 'moving-shot' technique under US or CT guidance. For lesions invading critical structures intolerant to 'en bloc' high-temperature RFA, limited-field EBRT using 6- or 10-MV photons was used for adjuvant treatment at a dose of 66 Gy in 33 daily fractions. Toxicities and outcomes were reviewed.
Results: Between April 2020 and January 2022, 11 patients with 14 rDTC lesions underwent RFA followed by EBRT. Five patients had metastatic lesions at rDTC diagnosis. With a median follow-up period of 33.7 months, all patients maintained locoregional control, while achieving a 2-year survival rate of 90.9%. This combined treatment achieved a volume reduction ratio of 92.1% ± 5.1%. The mean nadir thyroglobulin level in patients without initial distant metastases after treatment was 1.40 ± 0.81 ng/ml. Regarding treatment-related complications, one patient (9%) experienced temporary hoarseness after RFA, grade 2 radiation dermatitis occurred in 3 patients (27.2%), and grade 2 dysphagia was noted in 4 patients (36.4%). No grade 3 or greater toxicities occurred.
Conclusions: Salvage RFA followed by EBRT is feasible, effective and safe for patients with rDTC.

