Abstract Book 27th National Congress of the Italian Association of Medical Oncology (AIOM) - Impact of Adjuvant Oxaliplatin-Based Chemotherapy in Elderly Patients with Resected High-Risk Stage II or Stage III Colorectal Cancer: A Single-Institution Experience

BACKGROUND: Adjuvant (adj) oxaliplatin (OXA)-based chemotherapy (CT) improves prognosis in high-risk stage II and stage III resected colorectal cancer (CRC). However, its benefit in elderly patients remains unclear, as they are less frequently treated due to comorbidities, higher toxicity risk, and possibly reduced efficacy. METHODS: This single-centre retrospective study included patients with high-risk stage II or stage III resected CRC treated with OXA-based adj CT (FOLFOX or XELOX) at Policlinico Umberto I, Rome, from 2006 to 2023. The aim was to compare disease-free survival (DFS) and overall survival (OS) between fit elderly patients (>/= 70 years, with a G8 score >/= 14 or considered fit with a geriatric multidimensional assessment) and younger ones. Patients alive and recurrence-free 10 years after surgery were considered cured. Survival curves were estimated using the Kaplan-Meier method; comparisons were made using the log-rank test. Cox proportional hazards models were applied for univariate and multivariate analyses. Analyses were performed with RStudio v.2024.12.1. RESULTS: A total of 102 patients were included; 30 (29,4%) patients had a median age of 74 years (70-87 years). Younger patients (70,5%) had a median age of 61 years (44-69 years). Clinical-pathological characteristics (sex, TNM stage, sidedness, presentation) were balanced. Elderly patients had a worse performance status (PS 1–2, p=0.001) and more often received XELOX, while younger patients received FOLFOX (p=0.016). No differences were observed in dose reductions (p=0.9) or early discontinuation (p=0.4). After a median follow-up of 43 months, DFS did not differ significantly between groups. In multivariate analysis (age, sex, CCI, clinical presentation, TNM stage, sidedness, CT type, PS, dose reductions, discontinuations), only clinical presentation with perforation (HR 2.70, 95% CI 1.04–7.02, p=0.041) or occlusion (HR 6.92, 95% CI 2.19–21.9, p=0.001) was associated with worse DFS. Age >/= 70 years was the only independent predictor of worse OS (HR 2.88, 95% CI 1.09–7.58, p=0.032). CONCLUSIONS: Despite its retrospective nature and limited sample size, this study suggests that carefully selected elderly CRC patients may benefit from adj OXA-based CT. A further limitation is the lack of toxicity assessment. Prospective trials are needed to confirm its efficacy and safety in older populations.