Timing is everything: The importance of patient-reported outcome assessment frequency when characterizing symptomatic adverse events

Although patient-reported symptoms and side effects are increasingly measured in cancer clinical trials, an appropriate assessment frequency has not yet been established. To determine whether differences in assessment frequency affect the apparent incidence and severity of patient-reported symptoms using two well-established patient-reported outcome measures used within the same clinical trial.We examined patient-reported outcome results from AURA3 (NCT02151981), a randomized open-label study comparing Tagrisso (osimertinib) with platinum-based chemotherapy in patients with previously treated estimated glomerular filtration rate/T790M mutation-positive metastatic non-small cell lung cancer. The outcome of interest was the proportion of patients in each arm that reported worsening of nausea, vomiting, fatigue, diarrhea, constipation, and appetite loss from baseline measured using the patient-reported outcome-common terminology criteria for adverse event (weekly) or European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (every 6 weeks).Similar trends were observed for all six symptoms investigated. Using nausea in the chemotherapy arm as an example, 76% of patients reported any worsening from baseline based on weekly patient-reported outcome-common terminology criteria for adverse event assessments. When using an every 6-week assessment of Quality of Life Questionnaire Core 30 nausea and restricting analysis to an every 6-week assessment for patient-reported outcome-common terminology criteria for adverse event nausea, the proportion of chemotherapy arm patients reporting any worsening of nausea was 40% for both measures. Across the six patient-reported symptomatic adverse events, we observed differential proportions when comparing frequent versus sparse assessment.This analysis demonstrates that more frequent assessment of patient-reported symptomatic adverse events will lead to improved detection, and therefore a more complete understanding of the tolerability of experimental anti-cancer therapies.