Percutaneous radiofrequency and microwave ablation in the treatment of renal tumors - 10 years of experience

Safety and efficacy of RFA versus MWA for T1a renal cell carcinoma: a propensity score analysis

OBJECTIVES

Percutaneous radiofrequency ablation (RFA) is stated as a treatment option for renal cell carcinoma (RCC) smaller than 4 cm (T1a). Microwave ablation (MWA) is a newer technique and is still considered experimental in some guidelines. The objective of this study was to compare the safety and efficacy of RFA and MWA for the treatment of RCC.

METHODS

Patients with T1a RCC treated by RFA or MWA in two referral centers were retrospectively analyzed. Patient records were evaluated to generate mRENAL nephrometry scores. Local tumor progression (LTP) was considered when new (recurrence) or residual tumor enhancement within/adjacent to the ablation zone was objectified. Differences in LTP-free interval (residual + recurrence) between ablation techniques were assessed with Cox proportional hazards models and propensity score (PS) methods.

RESULTS

In 164 patients, 87 RFAs and 101 MWAs were performed for 188 RCCs. The primary efficacy rate was 92% (80/87) for RFA and 91% (92/101) for MWA. Sixteen patients had residual disease (RFA (n = 7), MWA (n = 9)) and 9 patients developed recurrence (RFA (n = 7), MWA (n = 2)). LTP-free interval was significantly worse for higher mRENAL nephrometry scores. No difference in LTP-free interval was found between RFA and MWA in a model with inverse probability weighting using PS (HR = 0.99, 95% CI 0.35-2.81, p = 0.98) and in a PS-matched dataset with 110 observations (HR = 0.82, 95% CI 0.16-4.31, p = 0.82). Twenty-eight (14.9%) complications (Clavien-Dindo grade I-IVa) occurred (RFA n = 14, MWA n = 14).

CONCLUSION

Primary efficacy for ablation of RCC is high for both RFA and MWA. No differences in efficacy and safety were observed between RFA and MWA.

KEY POINTS

• Both RFA and MWA are safe and effective ablation techniques in the treatment of T1a renal cell carcinomas. • High modified RENAL nephrometry scores are associated with shorter local tumor progression-free interval. • MWA can be used as heat-based ablation technique comparable to RFA for the treatment of T1a renal cell carcinomas.

Assessment of the Outcomes of Intrahepatic Cholangiocarcinoma After Ultrasound-Guided Percutaneous Microwave Ablation Based on Albumin-Bilirubin Grade

OBJECTIVE

To determine whether albumin-bilirubin (ALBI) grade could be used to predict the outcomes of patients with intrahepatic cholangiocarcinoma (ICC) who underwent ultrasound-guided percutaneous microwave ablation (MWA).

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. We studied 52 treatment-naïve patients with 74 ICC lesions according to the Milan criteria who subsequently underwent MWA from April 2011 to March 2018. Overall survival (OS) and recurrence-free survival (RFS) were compared in groups classified by Child-Pugh score and ALBI grade, which were statistically analyzed with the log-rank test. Cox proportional hazard regression analyses were used to determine the prognostic factors for survival in patients with ICC.

RESULTS

The median follow-up time was 21.2 months (3.2-78.7 months). Seventeen patients died during this period. After MWA, the cumulative 1-, 3-, and 5-year OS rates were 87.4%, 51.4%, and 35.2%, respectively, and the cumulative 1-, 3-, and 5-year RFS rates were 68.9%, 56.9%, and 56.9%, respectively. The major complication rate was 3.8% (2/52). Stratified according to ALBI grade, the cumulative 1-, 3-, and 5-year OS rates were 95.5%, 72.4%, and 72.4% for patients with ALBI grade 1 and 62.5%, 40.6%, and 36.3% for patients with ALBI grade 2, respectively, showing a significant difference (P = 0.006). Multivariate analysis results showed that older age (hazard ratio [HR]: 1.67, 95% confidence interval [CI]: 1.11-2.82; P = 0.002), tumor size ≥ 3 cm in diameter (HR: 11.33, CI: 2.24-34.52; P = 0.021) and ALBI grade (HR: 8.23, CI: 1.58-58.00; P = 0.004) may be predictors of poor OS.

CONCLUSION

ALBI grade was validated as a significant biomarker for predicting survival in ICC patients within the Milan criteria who underwent MWA.

Local ablation vs partial nephrectomy in T1N0M0 renal cell carcinoma: An inverse probability of treatment weighting analysis

Objective

To compare the survival outcomes of local ablation (LA) and partial nephrectomy (PN) for T1N0M0 renal cell carcinoma (RCC).

Method

We identified 38,155 T1N0M0 RCC patients treated with PN or LA in 2004‐2016 from the retrospective Surveillance, Epidemiology, and End Results databases. Among them, there were 4656 LA and 33,499 PN. A Cox proportional hazards regression model, cause‐specific Cox regression and Fine and Gray sub‐distribution hazard ratio (sHR) with inverse probability of treatment weighting (IPTW) adjusting was utilized to compare the effects of LA vs PN on all‐, RCC‐, and non‐RCC–caused mortality.

Results

Within the IPTW analysis, patients who underwent PN experienced a better overall survival (OS) (HR, 1.56; 95% CI, 1.40‐1.74; P < .001) and cancer‐specific survival (CSS) (HR, 2.21; 95% CI, 1.62‐2.98; P < .001) than LA patients. In the subgroup of patients >85 years (HR, 1.14; 95% CI, 0.73‐1.79, P = .577), chromophobe RCC (HR, 1.68; 95% CI, 0.94‐3.00, P = .078), and tumor size <2 cm (HR, 1.21; 95% CI, 0.95‐1.53, P = .126), the OS showed no significant difference between LA and PN. No significant difference in CSS between LA and PN was observed in the subgroup of chromophobe RCC (HR, 0.34; 95% CI, 0.03‐3.97, P = .389), and tumor size <2 cm (HR, 1.83; 95% CI, 0.92‐3.64, P = .084). For patients >85 years (sHR, 0.89; 95% CI, 0.52‐1.27, P = .520) and tumor size <2 cm (sHR, 1.14; 95% CI, 0.94‐1.38, P = .200), the non‐RCC–specific mortality was not significantly different in PN and LA cohorts, however, for the chromophobe RCC, the LA showed a worse non‐RCC mortality than PN (HR, 1.72; 95% CI, 1.06‐2.79, P = .028).

Conclusion

PN showed a better prognosis than LA in T1N0M0 RCC treatment, but LA and PN showed a comparable OS in elderly patients (>85), small RCC (<2 cm) and chromophobe RCC.

Phase I study of cancer lesion-targeted microwave coagulation therapy for localized prostate cancer: A pilot clinical study protocol

BACKGROUND

Whole-gland therapy for prostate cancer, which might cause more harm than no therapy (observation or active surveillance), might be a overtreatment. In order to avoid overtreatment as well as undertreatment of localize prostate cancer, novel strategy of organ-preserving therapies have been developed to achieve both cancer control and functional preservation. For the therapeutic techniques, microwave ablation would be an option for lesion-targeted focal therapy to eradicate biopsy-proven cancer lesion with its safety margin. Following our recent pilot clinical study of lesion-targeted focal cryotherapy, prospective clinical trial was designed to investigate the safety and therapeutic effects of lesion-targeted microwave therapy for localized prostate cancer.

METHODS

This is a single-center, phase I, clinical study to evaluate primarily the safety of lesion-targeted focal microwave treatment for prostate cancer. Patients with a magnetic resonance imaging (MRI)-visible, MR-ultrasound image-fusion targeted biopsy-proven clinically significant cancer will be enrolled. The target sample size is 5. Transrectal ultrasound-guided focal microwave ablation will be performed under general anesthesia. The primary endpoint is adverse events after microwave focal therapy. Secondary endpoint includes to assess both cancer control and quality of life (functional preservation).

DISCUSSION

This single-center, phase I, clinical study aims to evaluate the safety and efficacy of lesion-targeted focal microwave treatment for prostate cancer. The importance of this clinical trial is that it may establish new treatment for prostate cancer.

TRIAL REGISTRATION

This study was registered with Japan Registry of Clinical Trials (jRCTs052190026).