Characterization of chemotherapy-associated toxicity in patients aged 65 years and older with solid malignancies at a referral center in Colombia

Purpose: To describe the prevalence and types of chemotherapy-associated toxicities, in patients aged 65 years and older treated at a referral center in Colombia. Methods: A descriptive observational study was conducted among patients aged ≥65 years with solid tumors who initiated chemotherapy between July and October 2023 at a referral center in Bogotá, Colombia. Sociodemographic, clinical, functional, and oncologic variables including tumor stage, treatment regimen, and toxicity were collected using standardized tools. Descriptive statistics were applied for data analysis. Results: A total of 85 patients were included; 50.6% were male, with a median age of 71 years. Gastrointestinal neoplasms were the most frequent (60.5%), and 70.4% of patients were diagnosed at stage IV. According to the Cancer and Aging Research Group (CARG) toxicity tool, 59.2% presented an intermediate risk of severe toxicity. Chemotherapy-associated toxicity of any grade occurred in 69.1% of patients during the first 30 days and in 62.9% between 30 and 90 days after treatment initiation. Conclusions: Older adults exhibited a high prevalence of chemotherapy-associated toxicity, even at lower grades, which may impact symptom burden and treatment continuity. These findings emphasize the need for close monitoring and the validation of locally adapted predictive models for chemotherapy toxicity in this population.