Radiation Exposure From CT-Guided Ablation of Renal Masses: Effects on Life Expectancy

Abstract

OBJECTIVE. The purpose of this article is to project the effects of radiation exposure on life expectancy (LE) in patients who opt for CT-guided radiofrequency ablation (RFA) instead of surgery for renal cell carcinoma (RCC). MATERIALS AND METHODS. We developed a decision-analytic Markov model to compare LE losses attributable to radiation exposure in hypothetical 65-year-old patients who undergo CT-guided RFA versus surgery for small (≤ 4 cm) RCC. We incorporated mortality risks from RCC, radiation-induced cancers (for procedural and follow-up CT scans), and all other causes; institutional data informed the RFA procedural effective dose. Radiation-induced cancer risks were generated using an organ-specific approach. Effects of varying model parameters and of dose-reduction strategies were evaluated in sensitivity analysis. RESULTS. Cumulative RFA exposures (up to 305.2 mSv for one session plus surveillance) exceeded those from surgery (up to 87.2 mSv). In 65-year-old men, excess LE loss from radiation-induced cancers, comparing RFA to surgery, was 11.7 days (14.6 days for RFA vs 2.9 days for surgery). Results varied with sex and age; this difference increased to 14.6 days in 65-year-old women and to 21.5 days in 55-year-old men. Dose-reduction strategies that addressed follow-up rather than procedural exposure had a greater impact. In 65-year-old men, this difference decreased to 3.8 days if post-RFA follow-up scans were restricted to a single phase; even elimination of RFA procedural exposure could not achieve equivalent benefits. CONCLUSION. CT-guided RFA remains a safe alternative to surgery, but with decreasing age, the higher burden of radiation exposure merits explicit consideration. Dose-reduction strategies that target follow-up rather than procedural exposure will have a greater impact.

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

“…The radiation dose incurred during ablation was relatively higher than that of a single-phase contrast-enhanced abdominopelvic CT scan (5, 24). The median effective dose was 35.3 mSv during CT-guided RFA of liver tumors (25).…”

“…Many studies that examine long-term outcomes of patients with RCCs treated with RFA have not reported their radiation dose (1,2,3,4). Radiation dose is a serious problem because CT scans are commonly used before RFA, during RFA procedures, and during post-RFA follow-up (24). Therefore, the range, number, current, and voltage of RFA CT scans should be minimized as much as possible.…”

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

“…Use of both US and CT during the ablative procedure, might also increase the ability to immediately detect a vital unablated residual tissue, and thus to guide an immediate intraprocedural second ablation. The possible occurrence of an incomplete ablation is among the drawbacks of image-guided thermal ablations, and can particularly occur in case of large or centrally located tumors [30][31][32][33]. However, one of the principal aims of application of image-guided thermal ablation is to lower the invasiveness of treatment in frail patients unsuitable for surgery, or to minimize renal function damage particularly when surgery would require total nephrectomy.…”

Follow-up after focal therapy in renal masses: an international multidisciplinary Delphi consensus project

“…The toxicity of iodine contrast agents adds to the radiation burden especially when long survival is expected [24]. Both concerns are solved by using mpMRI with or without contrast, although availability and costs may constrain the use.…”