Perkutane computertomographiegezielte Radiofrequenzablation bei kleinen Nierentumoren

Enhancing the therapeutic impact of sublethal radiofrequency hyperthermia in malignant solid tumor treatment

Radiofrequency ablation (RFA) is an effective alternative to surgery for managing some malignant solid tumors. However, for medium-to-large tumors (>3 cm), tumors adjacent to large blood vessels, and certain irregular tumors, sublethal radiofrequency hyperthermia (RFH) often produces a margin of ablated tumor owing to the "heat-sink" effect. This effect typically leaves behind viable residual tumors at the margin. Several studies have reported that a sublethal RFH can significantly enhance the efficacy of chemotherapy, radiotherapy, immunotherapy, and gene therapy for malignant solid tumors. The possible mechanisms by which RFH enhances these therapies include heat-induced tissue fracturing, increased permeability of the cytoplasmic membrane, exaggerated cellular metabolism, blockade of the repair pathways of radiation-damaged tumor cells, and activation of the heat shock protein pathways. Therefore, RFA in combination with chemotherapy, radiotherapy, immunotherapy, or gene therapy may help reduce the rates of residual and recurrent tumors after RFA of malignant solid tumors.

Safety and oncological outcome following radiofrequency ablation of small renal masses in a single center

OBJECTIVE

To evaluate the safety and efficacy of percutaneous CT-guided radiofrequency ablation (RFA) for small renal masses (SRMs) at a large single-institution center during a period of 12 years.

MATERIALS AND METHODS

A total of 118 patients underwent RFA for SRM between July 2006 and July 2018 at our institution. We included demographic information, comorbidity, procedural details, and oncological outcome in the analysis. Survival analysis was performed using competing risk.

RESULTS

87 males and 31 females with median age 66 years underwent RFA. Median tumor size was 23 mm. Tumor biopsy was performed in 94% of cases, of which 56% were confirmed renal cell carcinoma (RCCs). Twenty-eight patients had benign tumors or underwent treatment for recurrence of prior RCC. Median follow-up of 5 years. Median Charlson Comorbidity Index was 5. Major complications occurred in 1.7%. No change in kidney function was observed. The initial treatment response was 98%. Among patients treated for newly diagnosed radiological suspected RCC without Von Hippel-Lindau or benign biopsy (90 pts), the cumulative incidence of radiological recurrence after 5 and 10 years was 6.6% (95% CI: 0.8-12%) and 16% (95% CI: 4.2-28%), respectively. Three patients died of RCC during follow-up. The cumulative incidence of kidney cancer death was 4.5% (95% CI: 4.3-13%) after 10 years. The incidence of other-cause mortality was 50% (95% CI: 34-67%).

CONCLUSION

CT-guided RFA is a safe and effective treatment option for patients unsuitable for surgery. RFA is a good alternative to partial or radical nephrectomy for SRMs, although randomized trials comparing surgery to minimally invasive thermal ablation techniques are missing.

Two Cases of Strictures after Percutaneous CT-Guided Radiofrequency Ablation for Renal Cell Carcinoma

Percutaneous radiofrequency ablation is a safe and effective minimally invasive treatment option in selected patients with T1a tumors of the kidney with a low complication rate. We describe two cases that developed the rare but severe complication of thermal injury-induced strictures of the upper urinary tract and its consecutive management.