A critical evaluation of the content validity of patient-reported outcome measures assessing health-related quality of life in children with cancer: a systematic review.

Following the COSMIN methodology, there is scarce evidence for the content validity of available PROMs for HRQOL in children with cancer. Most instruments were developed before the publication of milestone guidelines and therefore were not able to fulfill all requirements. Efforts are needed to catch up with methodological progress made during the last decade. Further research should adhere to recent guidelines to develop new instruments and to strengthen the evidence for existing PROMs.