Background: The EORTC QLQ-C30 Physical Functioning (PF) subscale is a widely used patient-reported outcome (PRO) measure that quantifies cancer patients’ physical function. Responsiveness, the degree to which a scale can assess clinical deterioration and improvement, is an important measurement characteristic that can be assessed by looking at floor and ceiling effects. A floor effect is defined as a high proportion of study participants reporting the lowest possible score in the variable of interest, while a ceiling effect is the opposite. We characterized floor and ceiling effects of the PF subscale in patients with breast cancer enrolled in commercial clinical trials vs. a community-based trial.Objectives: (1) Determine floor/ceiling effects of the QLQ-C30 PF items and subscale among patients receiving treatment for breast cancer (2) Compare floor/ceiling effects among patients enrolled in randomized clinical trials vs. those treated in a community care trial.Methods: PF data from 5 breast cancer commercial clinical trials submitted to the FDA for review were pooled (Clinical Trial or CT Cohort). A subgroup of breast cancer patients from the Alliance PRO-TECT trial was also analyzed (Community Cohort). Descriptive statistics were used to assess floor/ceiling effects, distributions of PF items, and the summed PF score at baseline and follow-up, for both cohorts. Results: The CT Cohort and Community Cohort consisted of 5,975 and 178 patients, respectively. Most patients in both cohorts were female, over the age of 50, and White. They were from varied treatment settings (adjuvant, 1st line, and 2nd line). 78% of CT patients had a baseline ECOG score of 0 (fully active), vs. only 44% in the Community Cohort. Baseline and follow-up floor effects (i.e. % of patients with the lowest response option - “not at all”) are presented in Table 1. Floor effects were more pronounced in the CT Cohort, with 43 to 94% of CT patients responding “not at all” to items in the PF subscale at baseline vs. 24 to 89% in the Community Cohort. Additionally, smaller proportions of CT patients responded “not at all” at Cycle 3 follow up compared to baseline. Meanwhile, floor effects in the Community Cohort were similar at baseline and month 3 follow up.Ceiling effects (i.e. % of patients with the highest domain response) were also observed in both cohorts. Over 54% of CT patients scored ≥93/100 on the 100-point PF subscale, at baseline. This proportion decreased to 30% at Cycle 3 follow up. On the other hand, 26% of community patients scored ≥93/100 on the PF subscale, at baseline. This proportion increased to 30% at Month 3.

Conclusion: We observed high floor/ceiling effects in the PF domain of the QLQ-C30 among patients in commercial clinical trials, more so than in the community. Inclusion of patient advocacy groups in the item selection process may increase the relevancy and sensitivity of the PF domain to the population being studied. Stakeholders in clinical trial and clinical practice settings may consider adding additional high functioning items from the EORTC’s item library, to more accurately determine the impact of anti-cancer treatment on patients’ physical functioning.

Table 1: Baseline and Follow Up Floor Effects - % of patients responding “not at all”

Clinical Trial CohortCommunity Cohort
BaselineCycle 3BaselineMonth 3
ItemQuestion% (n)% (n)% (n)% (n)
Do you have any trouble doing strenuous activities, like carrying a heavy shopping bag or a suitcase? 43% (2,540) 27% (573) 24% (42) 27% (43) 
Do you have any trouble taking a long walk? 60% (3,554) 28% (585) 24% (42) 30% (47) 
Do you have any trouble taking a short walk outside of the house? 88% (5,256) 68% (1,395) 58% (104) 64% (101) 
Do you need to stay in bed or a chair during the day? 73% (4,364) 57% (1,181) 46% (82) 51% (81) 
Do you need help with eating? 94% (5,599) 93% (1,904) 89% (159) 91% (145) 
Clinical Trial CohortCommunity Cohort
BaselineCycle 3BaselineMonth 3
ItemQuestion% (n)% (n)% (n)% (n)
Do you have any trouble doing strenuous activities, like carrying a heavy shopping bag or a suitcase? 43% (2,540) 27% (573) 24% (42) 27% (43) 
Do you have any trouble taking a long walk? 60% (3,554) 28% (585) 24% (42) 30% (47) 
Do you have any trouble taking a short walk outside of the house? 88% (5,256) 68% (1,395) 58% (104) 64% (101) 
Do you need to stay in bed or a chair during the day? 73% (4,364) 57% (1,181) 46% (82) 51% (81) 
Do you need help with eating? 94% (5,599) 93% (1,904) 89% (159) 91% (145) 

Citation Format: Meena N Murugappan, Bellinda King-Kallimanis, Christina Mangir, Lynn Howie, Vishal Bhatnagar, Julia A Beaver, Ethan Basch, Paul G Kluetz. Floor and ceiling effects in the EORTC QLQ-C30 physical functioning subscale among patients with breast cancer enrolled in commercial clinical trials vs. a community trial [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD12-12.