Geriatric Oncology Care in Brazil: Remote Geriatric Assessment-Driven Interventions With Supportive Care

The goal of this clinical trial is to determine whether a telehealth-delivered, geriatric assessment-guided supportive care program (GAIN-S) can improve health outcomes in older adults (age 65 and above) with solid tumors who are starting a new cancer treatment in Brazil. The main questions it aims to answer are: * Does GAIN-S improve physical function, as measured by activities of daily living (ADL), after three months? * Does GAIN-S reduce symptoms of depression and improve quality of life after three months? Researchers will compare patients receiving the GAIN-S intervention to those receiving standard care to see if the intervention leads to better physical function, fewer symptoms of depression, and improved quality of life. Participants will: * Complete a geriatric assessment (CARG-GA) before and after treatment. * Be randomized to either standard care or the GAIN-S intervention. * If assigned to GAIN-S, receive tailored supportive care via telehealth, which may include consultations with a psychologist, psychiatrist, nutritionist, geriatrician, exercise physiologist, or other specialists based on their needs.