Chemotherapy-Induced Toxicity

This study evaluates whether using specialized geriatric screening and toxicity prediction tools can help oncologists personalize chemotherapy dosing and reduce severe side effects in older adults with solid cancers. Older adults with cancer have diverse levels of physical resilience and functional reserve that standard oncologic performance scores often miss. Consequently, uniform standard chemotherapy dosing can lead to severe, life-threatening toxicities, unplanned hospitalizations, or early treatment discontinuation. In this prospective-retrospective comparative study, patients aged 65 years and older who are starting chemotherapy are prospectively evaluated using the Geriatric 8 (G8) screening tool. Patients identified as vulnerable (G8 score ≤ 14) undergo a Comprehensive Geriatric Assessment (CGA) across functional, nutritional, cognitive, and psychological domains. In addition, all prospective participants are evaluated using the Cancer and Age Research Group (CARG) toxicity tool to calculate their risk of severe side effects. Chemotherapy doses are risk-adapted based on CARG scores: * Low Risk: Standard chemotherapy dose * Intermediate Risk: 20% dose reduction * High Risk: 50% dose reduction Participants are followed every 3 months for 1 year to evaluate treatment tolerance, adherence, tumor response, and survival. These outcomes will be compared against a historical retrospective cohort of older patients with solid tumors who received standard-dose chemotherapy without G8 screening or CARG toxicity risk stratification.