Radiation risks of CT-guided removal of kidney masses remain low for adult patients, but the higher burden of radiation exposure on younger patients still needs careful consideration, according to a study published this month in the American Journal of Roentgenology.
As concerns about CT radiation exposure grow, particular attention is paid to patients whose procedures require multiple scans—similar to CT-guided renal mass removal, where patients are scanned multiple times to ensure accurate tumor location and probe placement, according to authors Jonathan D. Eisenberg, MD, with the Institute for Technology Assessment at Massachusetts General Hospital, and colleagues.
For this study, the authors looked at life expectancy (LE) in patients who underwent CT-guided radiofrequency ablation (RFA) instead of renal cell carcinoma (RCC) surgery.
“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,” Eisenberg and colleagues wrote.
The researchers found that the cumulative RFA exposures exceeded exposures from the surgery. In 65-year-old men, LE loss from radiation-induced cancers when comparing RFA to RCC surgery was 11.7 days—14.6 days for RFA as opposed to 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,” they wrote.
When studying dose-reduction strategies, Eisenberg and team found methods that focused on follow-up rather than procedural exposure had more 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,” they wrote.
Earlier exposure in a patient’s life, the authors noted, results in increased downstream risk relative to the amount of follow-up CT exams required. The exposure is relatively low, however, and the effects are minimal.
“Conversely, the exposure burden of surveillance imaging is so high that even though follow-up CT scans are likely to be performed at a time in which competing all-cause mortality risks steeply increase, their impact is greater than expected,” the team wrote. “Our analysis of exposure, risk, and LE loss illustrate why dose-reduction efforts specific to RFA for RCC must consider the procedure and surveillance together.”
Eisenberg and team suggest a patient-centered approach to dose reduction in interventional oncology that takes into consideration patient age, additional health risks and the full spectrum of radiation planned for the procedure.
“In this way, rational decision making can take place, in which risks, benefits, compromises, and trade-offs attend not only to a single imaging event but instead to the full horizon of a patient's care,” they concluded.