LBA 26 - Impact of Staging Laparoscopy on Tumor Control and Survival Comparison in Locally Advanced Gastric Cancer after Preoperative Chemoradiation vs. Preoperative Chemotherapy: Data from the Neo-CRAG Phase III Clinical Trial
Presenter(s)
Y. Zhang1, M. Jing1, J. Y. Tang1, W. Wang2, Y. Ling3, Z. W. Zhou2, and R. H. Xu4; 1Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou, China, 2Department of Gastric Surgery, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou, China, 3Department of pathology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou, China, 4Department of Medical Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou, China
Purpose/Objective(s): The multicentric phase III trial Neo-CRAG, comparing preoperative chemoradiation(CRT) with preoperative chemotherapy(ChT) in locally advanced gastric or EGJ (Siewert types II/III) adenocarcinoma, enrolled 620 patients and published its primary results as LBA in ASCO 2026. Clinical stage at enrollment needed to be cT3N2-3M0, cT4aN+M0, or cT4bNanyM0, but staging laparoscopy before randomization was not mandatory. This study is to report the impact of pre-treatment staging laparoscopy (PSL) on tumor control and survival comparisons in patients enrolled in our single institution.
Materials/Methods: 272 patients(pts) aged 26-75 years (median 61yrs) were included (as intent to treat (ITT) population). There were 197 males and 75 females, and 137 and 135 pts in the ChT and CRT groups, respectively. In both arms, patients received 3 cycles of XELOX chemotherapy followed by D2 gastrectomy and 3 cycles of adjuvant XELOX, with radiotherapy initiated after cycle 1 (45Gy/25Fx, concurrently with 2 cycles of dose-reduced XELOX) in CRT group. Radiation clinical target volume(CTV) chiefly included moderate mucosal expansion (3cm) in a fasting stomach, and elective regional LN (including 16a2 LN as the lower border). 126 pts received PSL, 2 of them (1 in each arm) got positive and censored. The primary endpoint was progression-free survival (PFS), the secondary endpoints included overall survival (OS), R0 resection, pathological response (pCR/MPR), and failure pattern.
Results: Per-protocol (PP) population consisted of 217 pts who completed the assigned preoperative treatments and gastrectomy, with 108 in ChT group and 109 in CRT group, respectively. After R0 resections, the rates of pCR (5.2% (5/96 pts) vs. 21.0%(22/105 pts)), ypT0 (5.2% vs. 23.8%), ypN0(29.2% vs. 60.0%), and MPR (NCCN-TRG 0-1,21.9% vs. 50.5%) were all improved significantly from ChT to CRT groups (p<0.01). In the ITT population, PSL got similar proportions in both arms, but it increased the PP treatment fulfillment (85.5% vs 76.0%, p=0.065), and improved R0 resection (83.1% vs 69.2%, p=0.010). After a median follow-up of 35.0 ms, CRT group got significantly improved PFS (3-yr PFS: 48.9% vs. 35.6%, p=0.029) and moderate better OS (5-yr OS: 47.4% vs. 43.2%, p=0.345) than ChT group. Locoregional recurrence(LRR) rates (10.5% vs. 21.9%) after R0 resection favored CRT compared with ChT (p=0.034). In the PP population, PSL did not alter the rates of R0 resection and pCR, nor that of LRR and tumor progression. In the ITT population, PSL significantly reduced tumor progression (52.4% vs. 70.5%, p=0.003), and improved PFS (3-yr PFS 50.8% vs. 35.8%, p=0.002) and OS (5-yr OS 54.1% vs. 38.5%, p=0.010).
Conclusion: This analysis supported the PFS and locoregional control benefits of preoperative CRT compared with preoperative ChT for locally advanced gastric cancer. PSL did not significantly change the pattern of failure after gastrectomy, but it significantly affected tumor progression and survival by promoting treatment completion.