Measurement Instruments Used to Assess Caregiver Burden in Informal Caregivers of Adult Cancer Patients: A Systematic Review

Background/Objectives: Caregiver burden is a relevant dimension of the caregiving experience among informal caregivers of cancer patients and is associated with psychological, physical, and social consequences. Although several instruments are available to assess the phenomenon, there is still limited consistency in the tools used across empirical oncology studies. Methods: A systematic review was conducted according to the PRISMA 2020 statement. A literature search was carried out in PubMed, Scopus, Web of Science, CINAHL, and PsycINFO up to February 2026. Quantitative studies assessing caregiver burden using standardized instruments in informal caregivers of adult cancer patients were included. Results: Thirteen studies met the eligibility criteria. The most frequently used instruments were the Zarit Burden Interview, followed by the Caregiver Burden Inventory. Less frequently used instruments included the Caregiver Reaction Assessment and the Caregiver Burden Scale. Most included studies relied on generic caregiver burden instruments originally developed outside oncology-specific contexts. Conclusions: Considerable heterogeneity exists in the instruments used to assess caregiver burden in oncology research. Empirical studies continue to rely predominantly on generic caregiver burden scales, while oncology-specific tools appear to be underused. Greater consistency in instrument selection may improve comparability across studies and support the integration of caregiver assessment into oncology practice.