Further content validation of the 18-item NCCN/FACT Ovarian Symptom Index and its Disease Related Symptom-Physical (DRS-P) subscale for use in advanced ovarian cancer clinical trials.

Findings support content validity of the NFOSI-18 and its DRS-P as originally constructed. We propose an alternative scoring option that excludes the item "I am sleeping well" from the DRS-P when used as a symptom-focused index for clinical research in a regulatory context.