Background: Radiation-induced emesis is an event linked to the release of serotonin during abdominal irradiation. Ondansetron is able to prevent emesis, but an optimal scheme has not yet been established. The aim of our study was to evaluate the efficacy of an escalating dose of oral ondansetron (Oral OND) in the prevention of emesis induced by fractionated radiotherapy.
Patients and methods: We enrolled 30 patients who underwent fractionated radiotherapy involving the upper abdomen which received this schedule of antiemetic therapy: phase A Oral OND 4 mg p.o. immediately after irradiation (RT) with a dose < or = 20 Gy; phase B Oral OND 8 mg p.o. immediately after RT with dose > 20 Gy and < 30 Gy; phase C Oral OND 8 mg p.o. every 12 hours starting immediately after RT with a dose > or = 30 Gy.
Results: During phase A we obtained a 100% of CR in all 30 patients. In phase B 22 CR (92%) and 2 MR (8%). In phase C on a total of 11 patients we recorded 6 CR (55%), 3 MR (27%) and 2 F (18%). The toxicity was mild.
Conclusion: Our data confirm the efficacy and safety of Oral OND and, moreover, show the possibility to reduce the cost without compromising the activity.