Survival outcomes of stages II-IV gastric cancer: A 13-year single center experience.

Abstract

e16091 Background: The management of locoregional and metastatic gastric cancers (Ga-Ca) has significantly changed, particularly with the introduction of anti-HER2 drugs and immunotherapy (IT). This study aims to describe outcomes of locoregional (stages II-IVA) and metastatic (IVB) Ga-Ca. Methods: This retrospective study included adult Pts (diagnosed with stages II-IV Ga-Ca, treated at Cleveland Clinic from 1/2010 - 12/2022. We excluded Pts who had Siewert classification 1+2 and Pts who did not receive systemic therapy. Data included demographics, clinical variables (ECOG, BMI, comorbidities), tumor stage, and all treatment modalities. Overall survival (OS) and progression-free survival (PFS) were calculated from diagnosis or treatment, as appropriate. Multivariable Cox proportional hazards models (CPH) were used to adjust for covariates. Results: Key baseline variables and survival outcomes are summarized in Table 1. In the locoregional disease (n = 194), 80 (41%), 102 (53%) and 12 (6.2%) had stages II, III and IVA, respectively. 78% had gastrectomy and 51% had radiation (RT). Pts received: Definitive chemoradiation (CRT) (n = 51, 31%), preoperative CRT + gastrectomy (18, 12%), adjuvant chemotherapy (CTX) + gastrectomy (45, 31%), pre/peri-operative CTX + gastrectomy (31, 21%) and other modalities. In preoperative CRT + gastrectomy, 7 Pts received carboplatin + paclitaxel (39%) and 7 received cisplatin + fluorouracil (39%). In the adjuvant group, 49% received FOLFOX. In pre/peri-operative group, 55% received FLOT. On multivariable CPH, compared to definitive CRT, pre/peri-operative CTX + gastrectomy was associated with improved OS (HR 0.52, P = 0.04) but not adjuvant + gastrectomy (HR 0.82, P = 0.4) or preoperative CRT + gastrectomy (HR 0.86, P = 0.6). Stages III & IVA had worse OS than stage II (P < 0.01). In metastatic disease (i.e., stage IVB), CTX with palliative RT was administered in 35 Pts (21%) and systemic therapy alone in 131 Pts (79%). Systemic therapy included: FOLFOX/ XELOX (n = 86, 52%), anti-HER2 therapy (8, 4.8%) and IT ± CTX (10, 6%). CTX with palliative RT was not associated with improved OS compared to systemic therapy alone (HR 1.23, 95%CI 0.83-1.83, P = 0.3). On multivariable CPH, IT ± CTX was associated with improved OS compared to FOLFOX/ XELOX (HR 0.4, 95%CI 0.18-0.9, P = 0.01). The combined benefit of modern regimens (IT ± CTX AND anti-HER2 + CTX vs . CTX) resulted in a 54% decrease in mortality (HR 0.46., 95%CI 0.24-0.9, P = 0.01). Conclusions: In this study, pre/peri-operative CTX + gastrectomy significantly improved OS in locoregional Ga-Ca. For metastatic Ga-Ca, modern systemic therapies, including IT and anti-HER2 treatments, demonstrated superior OS compared to conventional CTX regimens. Characteristic Stage II-IVAN=194 Stage IVBN=166 Median Age, yrs (IQR) 65 (57, 74) 66 (55, 74) Male 70% 68% White 75% 78% Never smoker 34% 41% Median follow-up, months 71 23 2-year OS 63% 19% Response rate 81% 54%