Background: Nausea and vomiting are commonly experienced by cancer patients, and can be assessed by the Functional Life Index-Emesis (FLIE) instrument which employs a three-day recall period. However, it is unknown whether patients' responses to the FLIE better correlate with the average or the worst symptom severity of the recall period, or the severity of an individual day.
Methods: Patients receiving emetogenic radiotherapy for painful bone metastases who were enrolled in one of three trials for anti-emetic medications (ondansetron, aprepitant/granisetron, or palonosetron) completed the FLIE at baseline, and days 3, 5, 7, or 10 during treatment and follow-up. The concordance correlation coefficient (rc) was calculated between FLIE overall nausea and vomiting and daily nausea, vomiting, and quality of life (QoL) using the average responses of the 3-day recall period and with each of the three days' responses.
Results: Responses from eighty-nine patients who experienced nausea or vomiting were analysed. The highest concordance for FLIE nausea was with the 3-day average [during treatment: rc =0.698, 95% confidence interval (CI): 0.495, 0.829; follow-up: rc =0.821, 95% CI: 0.711, 0.892]. FLIE vomiting had the highest concordance with worst day vomiting (during treatment, rc =0.310, 95% CI: 0.194, 0.417) or two day-prior vomiting (follow-up, rc =0.902, 95% CI: 0.832, 0.944). FLIE nausea and vomiting had inconsistent concordances with daily assessments of QoL.
Conclusions: Responses to the FLIE questionnaire are most representative of average nausea severity. Larger cohorts to validate these findings are warranted to address the lack of power in this present study and to confirm the wording and justification of a three-day recall period for the FLIE.
Keywords: Functional Life Index-Emesis (FLIE); Nausea; quality of life (QoL); radiation induced nausea and vomiting (RINV); recall period; vomiting.