Abstract

Background: Cancer chemotherapy has shifted from inpatient to outpatient settings where exposure of family members to hazardous drug is a serious concern.
Methods: We enrolled 5 female Japanese patients (age: 38.0 ± 20.5) who were administered cyclophosphamide (CPA) and thereafter immediately introduced to the bathroom. After urination, the lid of the toilet seat was closed, and excreta were drained twice. Sampling sheets on the surface and back of the toilet seat were collected and analyzed for CPA. The ability of wiping to eliminate experimental contamination was evaluated in a biological safety cabinet using 4 commercially available materials (10 squares of toilet tissue, 10 squares of toilet tissue soaked with 1 mL of water, thin and thick disposable cloths). CPA was added to a sampling sheet (Addition site) and another sampling sheet was set next to the addition site (Diffusion site). A wiper to test wiping effectiveness was placed 10 cm to the left of the additional site, a weight of 500 g was put on the wiper, and the weight was moved in 3 different wiping patterns (one direction (once and twice), outward and back (once)) at a speed of 1 cm/sec. The residual CPA in the addition and diffusion sites were analyzed.
Results: Average CPA on the surface and back side of the toilet seat for the five subjects was 15.2 and 121.2 ng, respectively. At the addition site, the residual CPA was less than 5 ng after wiping in one direction (once) with all materials. Recontamination with CPA was detected after wiping in one direction (twice) with the thin cloth and after wiping outward and back (once) with the thin and thick cloths. At the diffusion site, migration of CPA was detected after wiping in one direction (once) with the thin cloth.
Conclusion: These findings show that wiping off the back of the toilet seat is necessary after use of the restroom. When cleaning, protective measures are necessary to minimize exposure risk for family members, and wiping using 10 squares of toilet tissues soaked with water in one direction (once) is as an easy and simple method.