ESTRO 2023 - Abstract Book

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ESTRO 2023

groups respectively (odds ratio, 1.68; 95% confidence interval [CI], 0.59–4.78; P = 0.329). The adjusted cause-specific hazard ratio (HR) for disease-related treatment failure in patients treated with NCRT compared with SCRT was 0.31 (95% CI, 0.11–0.85; P = 0.024). The 3-year cumulative probability of disease-related treatment failure was 14.7% in the NCRT group vs 32.9% in the SCRT group. 3-year overall survival (87.9% vs 52.3%) was significantly better in the NCRT group (HR, 0.32; 95% CI, 0.10–0.99; P = 0.048). No significance difference in T-downstaging, N-downstaging, significant pathologic downstaging (ypT0-2N0), locoregional control and distant metastasis was detected. Thrombocytopenia and gastrointestinal toxicity were the most common preoperative grade ≥ 3 hematologic and non-hematologic toxicity, respectively. Grade ≥ 3 late rectal toxicity occurred in 10 (15%) patients in the NCRT group versus 2 (3%) in the SCRT group.

Figure 1. Cause-specific cumulative incidence of disease-related treatment failure (A), locoregional failure (B), and distant metastases (C), and overall survival curve (D).

Conclusion Based on our cohort, patients treated with NCRT and consolidation chemotherapy had a improved disease-related treatment failure and overall survival, despite a higher late rectal toxicity. Further studies to evaluate the long-term survival outcomes and toxicity are needed.