Radiation-induced emesis: a prospective observational multicenter Italian trial. The Italian Group for Antiemetic Research in Radiotherapy.

PURPOSE: A prospective observational multicenter trial was carried out to assess the incidence, pattern, and prognostic factors of radiation-induced emesis (RIE), and evaluate the use of antiemetic drugs in radiation oncology clinical practice. METHODS AND MATERIALS: Fifty-one Italian radiation oncology centers took part in this trial. The accrual lasted 2 consecutive weeks, only patients starting radiotherapy in this period were enrolled. Exclusion criteria were age under 18 years, and concomitant chemotherapy. Evaluation was based on diary cards filled in daily by patients during radiotherapy and 1 week after stopping it. Diary cards recorded the intensity of nausea and any episode of vomiting and retching. Prophylactic and symptomatic antiemetic drug prescriptions were also registered.
RESULTS: Nine hundred thirty-four patients entered the trial, and 914 were evaluable. Irradiated sites were: breast in 211 patients, pelvis in 210 patients, head and neck in 136 patients, thorax in 129 patients, brain in 52 patients, upper abdomen in 42 patients, skin and/or extremities in 37 patients, and other sites in 97 patients. Vomiting and nausea occurred in 17.1% and 37.3% of patients, respectively, and 38.7 % patients had both vomiting and nausea. At multifactorial analysis, the only patient-related risk factor that was statistically significant was represented by previous experience with cancer chemotherapy. Moreover, two radiotherapy (RT)-related factors were significant risk factors for RIE, the irradiated site and field size. In fact, a statistically significant higher percentage of RIE was registered in upper abdomen RT and RT fields > 400 cm2. Although nonstatistically significant, patients receiving RT to the thorax and head and neck presented a higher incidence of RIE. Only a minority (14%) of patients receiving RT were given an antiemetic drug, and the prescriptions were more often symptomatic than prophylactic (9% vs. 5%, respectively). Different compounds and a wide range of doses and schedules were used; however, there is some evidence from our data that in spite of antiemetic prophylaxis, 46% of patients had vomiting, and 58% had nausea. The majority (93%) of the prophylactic group received oral 5-hydroxytriptamine receptor (5-HT3) antagonist (8 mg/day, 7 days/week). In the symptomatic group, 54% and 41% patients received 5-HT3 antagonists and metoclopramide, respectively. At multivariate analysis, no patient- or RT-related risk factor for RIE was found to influence significantly the prophylactic or symptomatic use of antiemetics.
CONCLUSION: Our study provided useful data on epidemiology and characteristics of RIE. Previous chemotherapy, field size, and irradiated site (upper abdomen) were the only significant prognostic factors of RIE. A remarkable incidence of RIE was found in patients submitted to thoracic and head and neck RT. With this background of knowledge, it will be possible to better plan further studies on this important problem. Moreover, the low rate of antiemetics use and the wide variety of doses and schedules employed suggest the need to reinforce the "evidence based" approach to identify the best antiemetic approach to RIE.