Validity Testing of the Head and Neck Lymphedema and Fibrosis Symptom Inventory.

Lack of reliable and valid tools significantly impacts early identification and timely treatment of lymphedema and fibrosis (LEF) in the head and neck cancer population. To address this need, we developed and reported a patient-reported outcome measure (Head and Neck Lymphedema and Fibrosis Symptom Inventory [HN-LEF SI]). This article reports the construct validity (convergent and divergent validity) testing of the tool. A prospective, longitudinal, instrument validation study was conducted in patients with a newly diagnosed oral cavity or oropharyngeal cancer. Participants completed the HN-LEF SI and six carefully selected self-report measures at pretreatment, end-of-treatment, and every 3 months up to 12 months after treatment. Spearman correlations were used. A total of 117 patients completed the study. Patterns of correlations of the HN-LEF SI scores with the established self-report measure scores were consistent with expected convergent and divergent validity. Evidence from this work supports the construct validity of the HN-LEF SI.