Identification of meaningful individual-level change thresholds for worsening on the patient-reported outcomes version of the common terminology criteria for adverse events (PRO-CTCAE®)

Background We derived meaningful individual-level change thresholds for worsening in selected patient-reported outcomes version of the common terminology criteria for adverse events (PRO-CTCAE (R)) items and their composite scores. Methods We used two data sources, the PRO-TECT trial (Alliance AFT-39) that collected PRO-CTCAE data from adults with advanced cancer at 26 United States (U.S.) community oncology practices and the PRO-CTCAE validation study that collected PRO-CTCAE data from adults undergoing chemotherapy or radiation therapy at nine U.S. cancer centers or community oncology practices. Both studies administered selected PRO-CTCAE items and EORTC QLQ-C30 scales. Conceptually, relevant QLQ-C30 domains were used as anchors to estimate meaningful change thresholds for deterioration in corresponding PRO-CTCAE items and their composite scores. Items or composites with |rho| >= 0.30 correlation with QLQ-C30 scales were included. Changes in PRO-CTCAE scores and composites were estimated for patients who met or exceeded a 10-point deterioration on the corresponding QLQ-C30 scale. Change scores were computed between baseline and the 3-month timepoint in PRO-TECT, and in the PRO-CTCAE validation study between baseline and a single follow-up visit that occurred between 1 and 7 weeks later. For each PRO-CTCAE item, change scores could range from - 4 to 4; for a composite, change scores could range from - 3 to 3. Results Change scores in QLQ-C30 and PRO-CTCAE were available in 406 and 792 patients in PRO-TECT and the validation study, respectively. Across QLQ-C30 scales, the proportion of patients with a 10-point or greater worsening on QLQ-C30 ranged from 15 to 30% in the PRO-TECT data and 13% to 34% in the validation data. Across PRO-CTCAE items, anchor-based meaningful change estimates for deterioration ranged from 0.05 to 0.30 (mean 0.19) in the PRO-TECT data and from 0.19 to 0.53 (mean 0.36) in the validation data. For composites, they ranged from 0.06 to 0.27 (mean 0.17) in the PRO-TECT data and 0.22 to 0.51 (mean 0.37) in the validation data. Conclusion In both datasets, the minimal meaningful individual-level change threshold for worsening was one point for all items and composite scores.