Treatment Completion Rate, Toxicity, and 90-Day Unplanned Readmission in Older adults with Esophageal Squamous Cell Carcinoma Receiving Radiotherapy Alone Versus Concurrent Chemoradiotherapy

Abstract Background The optimal treatment for older adults (≥70 years) with esophageal squamous cell carcinoma (ESCC) remains controversial, with limited evidence comparing radiotherapy alone (RT) versus concurrent chemoradiotherapy (CCRT). Methods We conducted a single-center, retrospective, target trial emulation study of 432 patients aged ≥70 years with ESCC who received definitive RT (n = 214) or CCRT (n = 218) between 2016 and 2024. The primary outcome was treatment completion rate, defined as receipt of prescribed radiation dose for RT, and additionally achieving a relative dose intensity ≥80% for chemotherapy in the CCRT group. Key secondary outcomes included grade ≥3 toxicity and 90-day unplanned readmission. Inverse probability of treatment weighting was used to adjust for confounding. Results After adjustment, CCRT was associated with significantly lower treatment completion rates compared to RT (adjusted risk ratio [aRR] 0.86, 95% CI 0.79–0.93; absolute risk difference −13.5%). CCRT demonstrated higher rates of grade ≥3 toxicity (38.1% vs 17.8%; aRR 2.01), grade 4 toxicity (8.7% vs 2.3%; aRR 3.55), and 90-day readmission (21.6% vs 12.6%; aRR 1.72). Radiotherapy completion alone was also lower with CCRT (80.3% vs 88.3%; RR 0.91). Short-term tumor response was numerically higher with CCRT, at the cost of significantly increased toxicity. Effects were more pronounced in patients aged ≥75 years, those with Charlson Comorbidity Index ≥6, and frail patients (G8 ≤ 14). Conclusions In this real-world cohort of older adults with ESCC, CCRT was associated with significantly lower treatment completion rates and higher toxicity and readmission rates compared to RT alone. These findings highlight the importance of careful patient selection and shared decision-making when considering treatment intensification in older adults with ESCC.