MP796
PROJECTED CANCER RISK FROM MEDICAL IONIZING RADIATION PROCEDURES IN KIDNEY TRANSPLANTED PATIENTS

INTRODUCTION AND AIMS: Advances in medical imaging have been associated with increased ionizing radiation exposure. The relationship between radiation exposure and cancer risk shows a strong, good and reasonable evidence for doses >100 mSv, 50-100 mSv and 10-50 mSv, respectively. Retrospective studies confirmed an excess risk of cancer in adults who underwent computed tomography in childhood, while other Authors estimated the projected cancer risk, by estimating the Cumulative Effective Dose (CED) and Organ Doses (OD) and applying organ-specific cancer incidence or mortality data, as summarized in the Biological Effects of Ionizing Radiation (BEIR) VII report. Kidney Transplanted Patients (KTP) have higher risk of cancer compared to general population because of the uremic state and drug related immunosuppression. The aims of this retrospective study were to quantify the cumulative ED and OD to relevant organs and to assess the radiation-associated risk of cancer in KTP.

METHODS: KTP affering to our Center between 2007 and 2013 with a follow-up ≥1 year and without previous neoplastic history were enrolled. CED and OD were estimated from the Radiology Information System and Picture Archiving and Communication System of our Radiology Department. Radiation risk, expressed as Risk of Exposure-Induced Death (REID %) was estimated according to the BEIR VII model.

RESULTS: 102 KTP (69 males, mean age 53±13 years) were followed for a median of 5.3±1.3 years. During the follow-up 2980 radiological procedures were performed, accounting for 8194 mSv of ionizing radiation: conventional radiology, computed tomography and nuclear medicine accounted for 89%, 9% and 3% of the frequency but for 18%, 78% and 4% of the total CED. The total and annual mean (median) CED were 75±127 (29) mSv and 19±40 (5.6) mSv, respectively. 17% and 8% KTP received a total CED of 100-200 and >200 mSv, respectively. The mean cumulative OD were 151, 140, 137, 134,134 and 129 mGy for kidney, bladder, stomach, liver, uterus/ovarius and colon, respectively. The mean REID was 0.25±0.46%. 4% of KTP had REID > 1%.

CONCLUSIONS: KTP receive high CED from medical imaging; the excess cancer risk attributable to ionizing radiation exposure is not negligible. This should be of concern for nephrologists since KTP are living longer and have several concomitant risk factors for future cancer, including immunodepressive status.