Quantification of risk-benefit in interventional radiology

The increased use of interventional radiological procedures brings with it an increased risk of cancer induction due to the possible high radiation levels used. This risk must be balanced against any viable alternatives and should take into account the individual risks and benefits. The purpose of this study is to quantify this risk benefit in terms of quality-adjusted life years (QALYs) of a procedure and its alternatives, including the risk due to the radiation. Uterine fibroid embolisation was chosen as a model study with data collected both on the outcomes of procedures in terms of complications and quality of life in the long-term and on radiation dose delivered to the patient. Dosimetry data were obtained from University Hospital Galway. The risk was then calculated using the BEIR VII model of dose-response for low linear energy transfer (LET) radiation. In this case, it was found that the radiological technique has distinct advantages over hysterectomy and myomectomy in terms of QALYs. The increased risk due to radiation from the procedure is small when compared with the overall benefit to the patient. Probability of stochastic effects based on the average dose per procedure carries an attributable risk (fatal and non-fatal cancer and hereditary effects) of 0.4% or a relative risk of 1.09%. The method described here can readily be adapted to other interventional procedures.