712 CATAMNESTIC FOLLOW-UP OF RENAL CELL CARCINOMAS AMONG ATOMIC BOMB SURVIVORS ACCORDING TO RADIATION EXPOSURE STATUS

Abstract

INTRODUCTION AND OBJECTIVES: Over 65 years have passed since exposure to the atomic bomb (A-bomb) in Hiroshima. Many reports exist on radiation carcinogenesis in many carcinomas, and several prospective cohort studies were conducted. So far, however, there are few reports on the prognosis of A-bomb survivors versus patients not exposed to A-bomb radiation (non-exposed). We evaluated differences in prognosis of primary renal malignancies in A-bomb survivors and the non-exposed. METHODS: Of 479 patients who underwent nephrectomy at our hospital from March 1991 to December 2011, with renal cell carcinoma diagnosed in the resected specimen, 255 patients with evaluable cases in the postoperative course and birth month before June 1946, which included prenatal exposure to A-bomb radiation, were included. We retrospectively evaluated overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS) rates and analyzed patient clinicopathological findings. RESULTS: Of these 255 patients, 35 (13.7%) were A-bomb survivors. Mean age, sex, stage groupings, and histological classification and grade were similar between the A-bomb survivors and the non-exposed. Clinical T1 (cT1) patients were observed significantly more frequently among A-bomb survivors (32/35, 91.4%) than among the non-exposed (125/220, 56.8%; p 0.001). At a median follow-up of 47 months, OS rates at 5 and 10 years were 92.8% and 87.7%, respectively, in the A-bomb survivors and 74.6% and 69.3%, respectively, in the non-exposed (p 0.053). CSS rates at 5 and 10 years were 92.8% and 92.8%, respectively, in A-bomb survivors and 81.9% and 80.3%, respectively, in the non-exposed (p 0.137). DFS rates at 5 and 10 years were 92.7% and 92.7%, respectively, in A-bomb survivors and 86.7% and 83.7%, respectively, in the non-exposed (p 0.192). OS rates compared in cT1 patients showed no significant difference between A-bomb survivors and the non-exposed (p 0.690). In multivariate analysis, pT1 but not exposure of A-bomb was independent predictor for favorable prognosis. CONCLUSIONS: There was no difference in the prognosis of primary renal malignancies in A-bomb survivors and the non-exposed. Thus, the A-bomb does not seem to affect the prognosis of patients with renal cell carcinoma. Source of Funding: None