Cross-cultural adaptation of the Karnofsky Performance Status instrument to Brazilian Portuguese.

Introduction: The Karnofsky Performance Status (KPS) is one of the most widely used tools for assessing the prognosis of oncology patients, providing an estimate of treatment efficiency and survival. Despite this, it is commonly used in free translations without validation. The objective of the present study was to perform the cross-cultural adaptation of the KPS instrument to Brazilian Portuguese (KPS-BR) through the stages of conceptual, semantic, operational, measurement, and functional equivalences.