RESUMEN
PURPOSE: The time toxicity of anticancer therapy, defined as days spent with healthcare contact during treatment, represents a critical but understudied outcome. This study aims to quantify time toxicity among older patients with cancer receiving palliative systemic treatment. METHODS: All patients aged ≥ 65 years with metastatic cancer receiving cytotoxic chemotherapy, immunotherapy, or targeted therapy at a single center in Mexico were selected from a prospective patient navigation cohort. Patients completed a baseline assessment, including the G8 screening and quality of life measures. Physical healthcare contact days within the first 6 months were extracted from medical records and divided by days alive during the same period. Beta regression models were used to identify predictors of time toxicity. RESULTS: We identified 158 older patients (median age 71 years); 86% received cytotoxic chemotherapy. Seventy-three percent had an impaired G8 score and were considered vulnerable/frail. Six-month overall survival was 74%. Within the first 6 months, patients spent a mean of 21% (95% confidence interval (CI) 19-23%) of days with healthcare contact. Concurrent radiotherapy (odds ratio (OR) 1.55; 95%CI 1.21-1.97), cytotoxic chemotherapy versus targeted therapy (OR 1.64; 95%CI 1.13-2.37), and an impaired G8 (OR 1.27; 95%CI 1.01-1.60) were associated with increased time toxicity. CONCLUSION: Older adults with metastatic cancer spend 1 in 5 days with healthcare contact during treatment, with a higher burden of time toxicity for patients receiving radiotherapy or cytotoxic chemotherapy and those with potential frailty. These findings underscore the importance of informing patients about their expected healthcare contact days within the context of a limited life expectancy.