2092 - Selective Benefit of Adjuvant Chemoradiotherapy after Inadequate D2 Dissection in Gastric Cancer: A Multicenter Retrospective Comparative Study
Presenter(s)
A. Hossain1, S. Sultana2, N. T. Hossain3, S. A. Alam4, M. G. Z. A. Husna5, T. Hossain1, S. Taher6, and O. Faruque7; 1National Institute of Cancer Research and Hospital, Dhaka, Dhaka, Bangladesh, 2Delta Hospital Ltd, Dhaka, Bangladesh, 3Ahsania Mission Cancer and General Hospital, Dhaka, Bangladesh, 4National Institute of Cancer Research and Hospital., Dhaka, Bangladesh, 5National Institute Of Cancer Research & Hospital, Dhaka, Dhaka, Bangladesh, 6Evercare Hospital, Dhaka, Dhaka, Bangladesh, 7M A G Osmani Medical College, Sylhet, Sylhet, Bangladesh
Purpose/Objective(s): Suboptimal lymphadenectomy remains frequent in many regions, and the role of adjuvant chemoradiotherapy (CCRT) after upfront surgery with inadequate D2 dissection (<15 lymph nodes retrieved) remains uncertain. This study compared survival outcomes between adjuvant chemotherapy alone and chemotherapy followed by CCRT and explored whether high-risk pathological subgroups derive differential benefit.
Materials/Methods: A multi-center retrospective cohort from three institutions included patients undergoing upfront gastrectomy with inadequate nodal dissection. Consecutive eligible patients were screened, and a ratio-based stratified sampling strategy (1:2) was applied, selecting two chemotherapy-only patients randomly from records/database for each CCRT patient to minimize imbalance. The final cohort comprised 78 patients (CCRT=26; chemotherapy=52). Patients received 6–8 cycles of CAPOX, FOLFOX, or DCF, and the CCRT group subsequently received capecitabine-based concurrent radiotherapy. Endpoints included disease-free survival (DFS) and overall survival (OS). Stratified analyses were performed according to margin status, T stage, N stage, and tumor site.
Results:
Baseline clinicopathologic characteristics including age, sex distribution, tumor site, and stage were comparable between groups. Median DFS was numerically longer with CCRT (18 months vs 13 months) but was not statistically significant (p=0.206). Median OS was similar between groups (25 months vs 20 months for CCRT vs chemotherapy alone, p=0.255). Failure patterns were dominated by distant metastasis, with comparable locoregional relapse rates. Subgroup analysis suggested improved outcomes with CCRT among patients with advanced nodal disease (N2–N3, HR=0.31, 95% CI=0.12–0.79), whereas lower-risk patients showed minimal additional benefit. Isolated locoregional recurrence occurred in 15.4% vs 23.1%, and distant-only recurrence in 23.1% vs 28.1% for CCRT versus chemotherapy alone.Conclusion:
Inadequate D2 dissection remains a clinically relevant scenario in gastric cancer. Although routine addition of CCRT after adjuvant chemotherapy did not significantly improve OS in the overall cohort, patients with higher nodal burden appeared to derive greater benefit, supporting a risk-adapted approach to adjuvant radiotherapy. Prospective validation is warranted to define optimal patient selection where optimal lymphadenectomy is not consistently achieved.