Jonathan David Eisenberg BA, Presenter: Nothing to Disclose

Pari Pandharipande MD, MPH, Abstract Co-Author: Nothing to Disclose

Debra Ann Gervais MD, Abstract Co-Author: Research grant, Covidien AG

Michael Gilmore, Abstract Co-Author: Nothing to Disclose

Sarabjeet Singh MD, Abstract Co-Author: Nothing to Disclose

Mannudeep K. S. Kalra MD, Abstract Co-Author: Consultant, General Electric Company Faculty, General Electric Company

Bob Liu PhD, Abstract Co-Author: Nothing to Disclose

Chung Yin Kong PhD, Abstract Co-Author: Nothing to Disclose

G. Scott Gazelle MD, MPH, PhD, Abstract Co-Author: Consultant, General Electric Company Consultant, Marval Biosciences Inc

As younger, healthier patients consider CT-guided ablation for small renal cancers, there is a critical need to quantify cancer risks imparted by radiation from multiple procedural and follow-up CT scans. Our purpose was to project the effects of these exposures upon the life expectancy (LE) of patients who opt for CT-guided radiofrequency ablation (RFA) over surgery.

We developed a decision-analytic Markov model to estimate life expectancy for 65-year-old patients who undergo CT-guided RFA vs. surgery for small renal cancers. The model incorporated treatment effectiveness (higher for surgery), renal cancer-related mortality, radiation-induced cancer mortality, and all-cause mortality. Organ-specific exposures were estimated for RFA procedures and for CT scans after RFA and surgery. The BEIR VII report was used to estimate radiation risks. We compared LE for each strategy and quantified the contribution of radiation exposures to LE differences. Effects of varying model parameters - and of dose-reduction strategies - were evaluated in sensitivity analysis.

Cumulative radiation exposures to patients undergoing RFA (up to 355 mSv) substantially exceeded those for surgical patients (up to 66 mSv). For 65-year-old men, RFA yielded slightly lower LE (15.35 yrs) compared to surgery (15.40 yrs). Thirteen days of the 18-day-difference were due to radiation-induced cancer deaths. In younger patients, LE differences between RFA and surgery were greater. In 45-year-old men, LE after RFA was 47 days lower, 33 of which were due to radiation exposures. In 75-year-old men, these differences decreased to 7 and 5 days, respectively. Reducing CT doses, phases, or frequency substantially reduced LE differences. Women had greater radiation-related losses in all scenarios. Our results were otherwise stable over most parameter changes.

RFA remains a safe alternative to surgery in an elderly population with reduced life expectancy. Effects of radiation in younger patients are more pronounced and merit explicit consideration. Dose-reduction measures can positively affect the risk profile of RFA and warrant further investigation.

When young patients opt for CT-guided RFA instead of surgery for a renal mass, negative health effects from radiation exposure can be substantial and merit explicit consideration.

Eisenberg, J, Pandharipande, P, Gervais, D, Gilmore, M, Singh, S, Kalra, M, Liu, B, Kong, C, Gazelle, G, Radiation Exposures from CT-guided Ablation of Renal Masses: Effects on Life Expectancy.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11011873.html