Cancer Risk Assessment for Health Care Workers Occupationally Exposed to Cyclophosphamide Key Words Antineoplastic Agents * Biological Monitoring @bullet Occupational Exposure @bullet Cyclophosphamide * Cancer Risk Assessment

In the present study a cancer risk assessment of occupational exposure to cyclophosphamide (CP), a genotoxic carcinogenic antineoplastic agent, was car­ ried out following two approaches based on (1) data from an animal study and (2) data on primary and secondary tum ors in CP-treated patients. D ata on the urinary excretion of C P in health care workers were used to estimate the uptake of CP, which ranged from 3.6 to 18 p.g/day. Based on data from an animal study, cancer risks were calculated for a health care worker with a body weight of 70 kg and a working period of 40 years, 200 days a year (linear extrapolation). The life­ time risks (70 years) of urinary bladder cancer in men and leukemias in men and women were found to be nearly the same and ranged from 95 to 600 per million. Based on the patient studies, cancer risks were cal­ culated by multiplication of the 10-year cumulative incidence per gram of C P in patients by the estimated mean to ta l uptake in health care workers over 10 years, 200 days a year. The risk of leukemias in women over 10 years ranged from 17 to 100 per million using the secondary tum or data (linear extrapolation). C om para­ ble results were obtained for the risk of urinary bladder tumors and leukemias in men and women when pri­ mary tum or data were used. Thus, on an annual basis, cancer risks obtained from both the animal and the patient study were nearly the same and ranged from about 1.4 to 10 per million. In The Netherlands it is proposed that, for workers, a cancer risk per com pound P. J. M. Sessink ( £ 3 ) * R. P. Bos Department of Toxicoiogy, Faculty of Medical Sciences, University of Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands