3433 - Comparative Effectiveness of Neoadjuvant Chemoradiotherapy vs. Chemoimmunotherapy in Locally Advanced Resectable Esophageal Squamous Cell Carcinoma: A Multicenter Real-World Study

02:30pm - 03:45pm PT

Hall F

Screen: 7

POSTER

Presenter(s)

Hong Ge, MD - Henan Cancer Hospital, Zhengzhou, Henan

H. Ge¹, S. Yang², X. Zheng³, X. Wang⁴, X. Wang⁵, W. Zhang⁶, W. Huang⁷, and H. Wang⁸; ¹Department of Radiation Oncology, The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, China, ²Zhengzhou University Affiliated Cancer Hospital, Henan Cancer Hospital, Zhengzhou, Henan, China, ³Department of Radiation Oncology, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou, Henan, China, ⁴Cancer Hospital Chinese Academy of Medical Sciences, Beijing, China, ⁵Department of Radiation Oncology, Anyang Cancer Hospital, Anyang, China, ⁶Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China, ⁷Shandong Cancer Hospital & Institute, Jinan, Shandong, China, ⁸Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China

Purpose/Objective(s): The efficacy of neoadjuvant chemoradiation(nCRT) compared to neoadjuvant chemotherapy combined with immunotherapy (nCIT) followed by esophagectomy has rarely been evaluated in locally advanced esophageal squamous cell carcinoma (ESCC). The study aimed to comparative analysis of survival outcomes between 2 neoadjuvant treatment regimens.

Materials/Methods: We analyzed data from 1000 ESCC patients with clinical stages cT1b-2N+ and cT3-4aNx across 6 Chinese cancer institutes from Jan 2019 to Dec 2023. Propensity score matching (PSM) was performed based on sex, age, smoking history, alcohol consumption, tumor location, and cTNM stage. Inverse probability weighting (IPW) was additionally applied to address potential confounding. The primary endpoints were overall survival (OS) and event-free survival (EFS), while secondary endpoints included pathological complete response (pCR), R0 resection rate, recurrence rates and treatment-related adverse events (TRAEs).

Results: After matching, 976 patients (488 in each group) were analyzed. The 1-year, 2-year, and 3-year OS rates for the nCRT group were 95.1%, 85.6%, and 79.7%, respectively, while for the nCIT group, they were 94.3%, 84.3%, and 77.9%. PSM analysis showed similar OS rates for both groups (nCRT: 95.1%, 85.6%, 79.7%; nCIT: 94.1%, 84.0%, 77.1%). The EFS rates for the nCRT group at 1, 2, and 3 years were 86.4%, 77.5%, and 74.2%, respectively, compared to 85.5%, 76.6%, and 73.9% for the nCIT group (PSM-adjusted EFS: nCRT: 86.4%, 77.5%, 74.2%; nCIT: 85.2%, 76.5%, 73.7%). IPW analysis indicated that the OS difference between the 2 groups was not statistically significant (HR 0.84, 95% CI 0.63-1.12, P=0.51), and similarly, the EFS difference was also not statistically significant (HR 0.84, 95% CI 0.63-1.12, P=0.93). The pCR rate was significantly higher in the nCRT group (39.96%, 195/488) compared to the nCIT group (23.57%, 115/488, P<0.0001). The R0 resection rate was 98.76% (478/488) in the nCRT group versus 96.72% (472/488) in the nCIT group (P=0.0099). The recurrence rates were comparable between the 2 groups (nCRT: 26.79%,vs. nCIT: 23.20%, P=0.21). The incidence of AEs was higher in the nCRT group (95.5% vs. 90.3%, P=0.004), with hematologic toxicity being more prevalent, while the nCIT group exhibited higher rates of thyroid dysfunction and liver enzyme abnormalities.

Conclusion: nCIT showed comparable survival outcomes in resectable locally advanced ESCC, suggesting nCIT may serve as a viable alternative. Prospective trials are warranted to validate these findings and explore long-term outcomes.

Abstract 3433 - Table 1

Variables		Before PSM		P value	After PSM		P value
		nCRT	nCIT		nCRT	nCIT
		n(488)	n(512)		n(488)	n(488)
Age,years	Median	62	64		62	63
Sex,n(%)	Male	413(84.6)	418(81.6)	0.24	413(84.6)	402(82.4)	0.34
	Female	75(15.4)	94(18.4)		75(15.4)	86(17.6)
Clinical stage,n(%)	I-II	120(24.6)	116(22.7)	<0.01	120(24.6)	100(20.5)	<0.01
	III	259(53.0)	336(65.6)		259(53.0)	328(67.2)
	IVA	109(22.4)	60(11.7)		109(22.4)	60(12.3)