ObjectivesPatients with advanced lung cancer (LC) face significant physical, psychological, and functional challenges, increasing their reliance on caregivers. This study evaluates the efficacy of CareSTEPS (Self-Care, Stress management, Symptom management, Effective communication, Problem-solving, and Social support), a 6-week telephone-delivered intervention designed to improve psychological functioning (depression and anxiety symptoms) and reduce caregiver burden among family caregivers of patients with advanced LC. MethodsIn this multisite, open-label, parallel-group randomized controlled trial, 174 caregivers (74.1% female individuals, 40.2% from a racial or ethnic minority group) of patients with stage IIIB or IV NSCLC or extensive-stage SCLC completed baseline surveys and were randomly assigned to CareSTEPS (n = 87) or usual care (n = 87) using stratified block randomization. Caregivers in the CareSTEPS arm received a manual with information on self-care, stress management, symptom management, effective communication, problem-solving, and social support. They also participated in six weekly telephone sessions with Masters-level trained interventionists with a mental health background, who provided psychoeducation, skills training, and support. Eight weeks after baseline, caregivers completed a follow-up survey. ResultsUsing an intent-to-treat framework, analyses of covariance were conducted to assess the efficacy of CareSTEPS, with p values lower than 0.05 indicating significant differences. Caregivers who received CareSTEPS reported improved psychological functioning and lower burden compared with those who received usual care, with effect sizes ranging from small to large (depression d = −0.55, anxiety d = −0.81, burden d = −0.37). ConclusionsThe CareSTEPS intervention reports great promise in meeting the critical support needs of the family caregivers of patients with advanced LC, significantly improving caregivers' psychological functioning and reducing their burden. Overall, the findings emphasize the importance of incorporating caregiver support into the comprehensive management of advanced LC. Clinical Trial RegistrationClinicalTrials.gov NCT02414672.