A prospective cohort study of patient-reported vomiting, retching, nausea and antiemetic use during neoadjuvant long-course radiation therapy and concurrent 5-fluorouracil-based chemotherapy for rectal adenocarcinoma

BACKGROUND AND PURPOSE: Antiemetic guidelines suggest daily prophylaxis with a serotonin(3) receptor antagonist (5-HT(3)RA) as an option for patients receiving long-course neoadjuvant radiation therapy and concurrent 5-fluorouracil-based chemotherapy for rectal cancer, despite the risks that 5-HT(3)RA-induced constipation may pose. We explored the incidence of patient-reported vomiting, retching, nausea and antiemetic intake among patients in this setting to determine if these risks are justified. MATERIALS AND METHODS: We carried out a single-centre non-randomised prospective cohort study of adult patients receiving long-course neoadjuvant radiation therapy and concurrent 5-fluorouracil-based chemotherapy for rectal adenocarcinoma. Patients recorded symptoms and medication intake daily until 7 days following treatment completion. RESULTS: From 33 evaluable patients, we collected 1407 days of patient-reported data. Vomiting was reported by 7 patients (21%), retching by 5(15%) and nausea by 21(64%). No patients were administered prophylactic antiemetics. The median number of days with vomiting was 2, and the cumulative number of days for all affected patients was 22 (1.6% of 1407 evaluable days). There were no differences in PTV or small bowel loop V15Gy, V45Gy and V50Gy volumes between patients that did and did not vomit. CONCLUSIONS: The cumulative incidence of days with vomiting was only 1.6%. 5-HT(3)RA prophylaxis during long-course neoadjuvant treatment seems unnecessary.