Psychometric validation of the Female Sexual Function Index (FSFI) in cancer survivors

The Female Sexual Function Index (FSFI) is the most commonly used self-report instrument to measure sexual functioning among women cancer survivors. Despite this, the validity and reliability of the FSFI for use in cancer populations has not been established.

Data were combined from 3 separate institutional review board-approved studies of the psychosexual adjustment of women cancer survivors conducted at Memorial Sloan-Kettering Cancer Center. Psychometric analysis was applied to the FSFI responses from 181 women comprising 4 cohorts, including survivors of: gynecologic cancer (all types; 2 cohorts), malignancies requiring bone-marrow/stem cell transplantation, and early stage cervical cancer.

A factor analysis supported the subscale structure of the FSFI, yielding results nearly identical to those from the original FSFI validation study. Internal consistency reliability was 0.94 for the FSFI total score and ranged from 0.85 to 0.94 for the domain scores. Corrected item-total correlations ranged from 0.44 to 0.79 for the total score and from 0.62 to 0.88 for the domain scores. FSFI scores were correlated negatively with measures of depression, distress, and menopausal symptoms and were correlated positively with quality of life. FSFI scores exhibited a preliminary ability to discriminate between women based on whether or not they received chemotherapy and/or radiation.

The FSFI demonstrated strong psychometric properties in this study, supporting its continued use for monitoring sexual function and cancer-related dysfunction among sexually active women who are cancer survivors.