Psychometric evaluation of the FACT Colorectal Cancer Symptom Index (FCSI-9): reliability, validity, responsiveness, and clinical meaningfulness.
BACKGROUND
Patient-reported outcomes (PROs) are essential for evaluating treatment effects on health-related quality of life and symptoms from the patient's perspective. This study sought to evaluate the psychometric properties of the nine-item Functional Assessment of Cancer Therapy/National Comprehensive Cancer Network Colorectal Cancer Symptom Index (FCSI-9) in a metastatic colorectal cancer (mCRC) population.


METHODS
The FCSI-9 and EQ-5D were administered every 2-4 weeks to mCRC subjects in a phase III clinical trial. Three hundred ninety-one mCRC subjects completed the questionnaires at baseline and at least one follow-up assessment. Internal consistency reliability, test-retest reliability, construct validity, known groups validity, responsiveness, and the minimum important difference (MID) of the FCSI-9 were evaluated.


RESULTS
The internal consistency and test-retest reliability of the FCSI-9 were acceptable (0.81 and 0.76, respectively). Construct validity was supported based on moderate correlations with the EQ-5D. Known groups validity was evaluated by examining the FCSI-9 scores of subjects categorized by their Eastern Cooperative Oncology Group performance status (PS) score. Subjects with better PS scores reported significantly higher FCSI-9 scores than those with lower PS scores at both baseline and week 8. Responsiveness, as measured by Guyatt's statistic, was 0.77 from baseline to week 8 and 0.60 from week 4 to week 12. Considering all data together, the MID of the FCSI-9 is estimated to be in the range of 1.5-3.0 points.


CONCLUSIONS
Results provide preliminary evidence of the reliability, validity, and responsiveness of the FCSI-9.
Colwell
Hilary H
HH
ICON Clinical Research, Lifecycle Sciences Group, 188 Embarcadero, Suite 200, San Francisco, California 94105, USA. hilary.colwell@iconplc.com
Mathias
Susan D
SD
Turner
Michelle P
MP
Lu
John
J
Wright
Nicola
N
Peeters
Marc
M
Cella
David
D
Devercelli
Giovanna
G
D000368:Aged; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care / Q000379:methods*; D010166:Palliative Care; D000077544:Panitumumab; D010358:Patient Participation; D017060:Patient Satisfaction; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D000077544:Panitumumab