Real-world treatments and outcomes in metastatic and recurrent esophageal squamous cell carcinoma in Japan: a retrospective analysis using the Millennial Medical Record database

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) remains a significant clinical challenge in Japan. Real-world data on treatment patterns and outcomes, particularly for patients unfit for cisplatin, remain limited. This study evaluated characteristics, treatments, and outcomes of patients newly diagnosed with metastatic ESCC (mESCC) or recurrent ESCC (rESCC). METHODS: A retrospective cohort analysis was conducted using the Millennial Medical Record database (December 2021-June 2024), including patients with m/rESCC. Patients receiving first-line (1 L) systemic therapy were categorized into cisplatin or non-cisplatin groups. Key outcomes included time-to-treatment discontinuation and overall survival (OS). RESULTS: Among 155 patients, 52.3% had mESCC and 47.7% had rESCC; 31.0% received 1 L systemic therapy, 46.4% underwent surgery or radiotherapy, and 22.6% received no treatment. Among those receiving 1 L therapy, 58.3% were treated with immune checkpoint inhibitors (ICIs), either in combination with chemotherapy or alone. Non-cisplatin patients were older with greater comorbidity burden; ~33.3% receiving ICI monotherapy and 27.8% dual ICI therapy. In contrast, 56.7% of patients in the cisplatin group received a cisplatin-ICI combination. Treatment discontinuation was more frequent with cisplatin than non-cisplatin therapy (73.3% vs. 55.6%), despite longer median treatment duration (75 vs. 47 days). Twelve-month OS was higher with cisplatin than non‑cisplatin regimens (92.1% vs. 75.0%). CONCLUSIONS: In this real-world Japanese study, cisplatin-based regimens were commonly used for m/rESCC. Many patients who did not receive cisplatin had differing outcomes. This highlights the unmet need for better-tolerated alternatives for cisplatin-unfit patients with ESCC in Japan.