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.

This is a multicenter, randomized controlled trial evaluating the effectiveness of a telehealth-delivered, geriatric assessment-guided intervention (GAIN-S) in improving health outcomes for older adults with solid tumors who are initiating a new systemic cancer therapy (chemotherapy, immune checkpoint inhibitors, and/or tyrosine kinase inhibitors) in Brazil.

The intervention is adapted from the Geriatric Assessment and Intervention Network (GAIN) model and integrates multidisciplinary supportive care services delivered remotely. The study is conducted across 14 oncology practices, including both private and public institutions, located in the Midwest, South, Southwest, and North regions of Brazil.

A total of 350 participants aged 65 years and older will be enrolled and randomized 1:1 to either the GAIN-S intervention or standard of care (SOC). All participants will complete a validated geriatric assessment (CARG-GA) at baseline and again at 3 months. The CARG-GA evaluates functional status, comorbidities, psychological well-being, nutrition, cognitive status, social support, and fall risk.

In the intervention arm (GAIN-S), patients will receive a tailored set of supportive care services based on their GA results. The multidisciplinary team-consisting of a medical oncologist, geriatrician, psychologist, psychiatrist, nutritionist, and exercise physiologist-will review the GA findings and deliver recommendations via telehealth (e.g., video calls or phone). Patients may receive one or more remote consultations from team members depending on their individual needs.

In the SOC arm, GA results will be shared with the treating oncologist, but no structured intervention will be implemented unless a critical issue is identified (e.g., severe depression or cognitive impairment), in which case referrals may be made.

The primary outcome is change in physical function (Activities of Daily Living - ADL) from baseline to 3 months. Secondary outcomes include changes in depression symptoms (Geriatric Depression Scale - GDS) and health-related quality of life (FACT-G) from baseline to 3 months.

In addition to the main trial, a separate feasibility study will be conducted to evaluate the implementation of the GAIN-S intervention in public hospital settings. This feasibility study will recruit 50 patients from public hospitals in Brazil and will assess the practicality, acceptability, and potential barriers to delivering geriatric telehealth interventions in resource-limited environments.

The study aims to address key gaps in cancer care delivery for older adults in low- and middle-income countries, where access to geriatric-trained oncology professionals is limited. The use of telehealth and standardized GA tools seeks to provide a scalable model for personalized care and improve outcomes in this underserved population.

Inclusion Criteria:

• Age 65 years or older at time of enrollment
• Diagnosed with a solid tumor cancer of any stage
• Scheduled to start a new systemic cancer therapy (chemotherapy, immune checkpoint inhibitors, and/or tyrosine kinase inhibitors)
• Able to provide written informed consent
• Physician approval for participation

Exclusion Criteria:

• Inability or unwillingness to comply with study procedures, including telehealth visits
• Cognitive or other impairments precluding participation as determined by the investigator
• Any condition that, in the investigator's opinion, would make the patient unsuitable for the study or interfere with study assessments

The decision regarding sharing individual participant data (IPD) is currently under consideration. Factors such as participant privacy, ethical approvals, and logistical aspects will be evaluated before a final plan is established. Updates on data sharing intentions will be provided as the study progresses.

This is an open-label trial because:

• Participants know if they are receiving the GAIN-S intervention.
• The care providers and multidisciplinary team also know which arm the participant is in.
• Masking is not feasible due to the nature of the intervention (telehealth and tailored supportive care).