Purpose: To document the incidence and timing of radiotherapy-induced nausea and vomiting (RINV) in the treatment of bone metastases among patients receiving prophylaxis with a 5-HT(3) receptor antagonist.
Methods: Patients receiving single (SF) or multiple fraction (MF) palliative radiotherapy (RT) of moderate or low emetogenic risk for bone metastases were prescribed prophylactic Ondansetron. The frequency and duration of prophylaxis and the use of rescue antiemetics were left to the discretion of the treating physicians. Patients documented episodes of nausea (N) and vomiting (V) in daily diaries before and during RT, and until 10 days following RT completion. Rates of complete prophylaxis (CP) for N&V, respectively (CP = no event and no rescue medication), were calculated for the acute phase (the period from the start of RT to the first day following RT completion inclusive) and the delayed phase (the second to tenth days following RT completion inclusive).
Results: Fifty-nine patients were enrolled, and 32 were evaluable. CP rates were as follows: moderate-risk SF group (n = 16), acute phase (CP for N = 56%, CP for V = 69%) and delayed phase (CP for N = 31%, CP for V = 44%); moderate-risk MF group (n = 7), acute phase (CP for N = 71%, CP for V = 57%) and delayed phase (CP for N = 43%, CP for V = 57%); low-risk SF group (n = 8), acute phase (CP for N = 50%, CP for V = 100%) and delayed phase (CP for N = 43%, CP for V = 57%); and low-risk MF group (n = 1), acute phase (CP for N = 100%, CP for V = 100%) and delayed phase (CP for N = 100%, CP for V = 100%).
Conclusions: Despite prophylaxis, RINV was common among patients receiving palliative radiotherapy for bone metastases, especially during the delayed phase.