Real-world treatment patterns and biomarker testing landscape of locally advanced gastric/gastroesophageal junction cancer (LA GC/GEJC) in China (SURPASS study).

Abstract

304 Background: The treatment landscape for resectable locally advanced gastric/gastroesophageal junction cancer (LA GC/GEJC) in China is evolving from adjuvant to perioperative therapy. Treatment recommendations vary significantly between the West and East, with differences in chemotherapy regimens and target patient populations. The exploration of immunotherapy (IO) in resectable LA GC/GEJC is further complicating the treatment landscape. This study aims to evaluate the treatment and biomarker testing patterns in resectable LA GC/GEJC in Chinese real-world setting. Methods: This quantitative survey was conducted from July to November 2024 across tier 1 to tier 5 cities in China, targeting 254 clinicians (158 medical oncologists, 80 surgeons, 16 radiation oncologists) selected by stratified random sampling. Descriptive analysis and inferential statistics were applied. Results: For clinical stage II (cII) resectable GC/GEJC, 74.0% of clinicians preferred postoperative adjuvant therapy, while only 20.1% favored perioperative therapy. In contrast, for stage cIII and cIVa resectable GC/GEJC, perioperative therapy was the predominant choice, chosen by 71.2% and 90.9% of clinicians, respectively. For perioperative therapy, the top 3 regimens chosen were SOX (47.2%), IO-containing regimens (43.7%), and XELOX (42.9%). For adjuvant therapy, the leading regimens were XELOX (72.8%), SOX (67.3%), and FOLFOX (39.8%). Regarding unresectable LA GC/GEJC, 61.4% of clinicians favored conversion therapy. The most commonly chosen regimens for this approach were IO-containing regimens (62.2%), SOX (33.9%), and triplet regimens (28.0%). Out of 254 clinicians surveyed, 230 had prescribed PD-L1 testing, with a median patient testing rate of 70%. Among these, 69.1% (159/230) of clinicians used Combined Positive Score (CPS) as scoring method. Based on PD-L1 status, 32.9% of clinicians chose IO-containing regimens regardless of PD-L1 expression, while 51.3% reserved these regimens for patients with PD-L1 positive expression (≥1, 5, or 10) in the neoadjuvant setting of resectable LA GC/GEJC. For conversion therapy of unresectable LA GC/GEJC, these proportions were 43.0% and 49.6%, respectively. 230 of 254 clinicians had prescribed MSI/MMR, with a median patient testing rate of only 18%. For MSI-H/dMMR resectable LA GC/GEJC, clinicians most often chose IO-containing regimens in neoadjuvant (86.9%), adjuvant (70%), and conversion (94.3%) settings. Conclusions: In China, perioperative treatment is primarily used for stage cIII and cIVa resectable GC/GEJC. The chemotherapy backbone for resectable LA GC/GEJC typically involves doublet regimens. Most clinicians adopt IO-based therapies guided by PD-L1 and MSI status; however, biomarker testing rate and standardization remain inadequate and need improvement.