Aims: Patient perception of treatment side effects is an important consideration in oncology. A single global item measure of side effect bother may be useful in summarising this information. We assessed if a single item measuring side effect bother could discriminate between trial arms of varying safety profiles.
Methods: This was a retrospective analysis of data from three registration trials with different relative toxicity profiles for the investigational arm. The Functional Assessment of Cancer Therapy (FACT) GP5 item assesses the degree of side effect bother on a 0-4 point scale (0=not at all, 4=very much). We compared the proportion of patients across trial arms reporting “any” bother (GP5 scores > 1) and “high” bother (GP5 scores > 3) at any time during the first six months on treatment. Clinician-reported adverse event (AE) data were evaluated using the Common Terminology Criteria for Adverse Events (CTCAE), with; grade 3+ results considered “high-grade.”
Results: Over 80% of patients had a CTCAE AE of any grade for both investigational (I) and Control (C) arms. Patient reports of “any” bother results differed across arms in each trial during the first six months: breast (I: 66.4%, C: 42.9%), renal (I: 65.6%, C: 86.9%) and prostate (I: 63.1%, C: 57.5%). High-grade AEs were more frequent in the investigational arm of the breast (I: 49.7%, C: 13.1%) and prostate (I: 45.1%, C: 34.2%) trials, and less frequent for the renal trial (I: 65.3%, C: 76.1%). Patient reports of “high” bother were consistent with this: breast (I: 14.0%, C: 3.6%), renal (I: 10.6%, C: 36.4%) and prostate (I: 14.6%, C: 8.5%).
Conclusions: These preliminary findings suggest a single global item may discriminate between arms in cancer trials with differing levels of high-grade toxicity. Further analysis of this item will provide greater insight into its utility in trials.