1465P - A nationwide population-based study comparing treatment patterns and outcomes in synchronous versus metachronous metastatic esophageal and gastric adenocarcinoma

Background

Real-world data on treatment patterns and outcomes in synchronous versus metachronous metastatic disease in esophagogastric adenocarcinoma are not available. The aim of our study was to compare patient and tumor characteristics, first-line systemic treatment, overall survival (OS) and time to treatment failure (TTF) in patients with synchronous versus metachronous metastatic esophageal and gastric adenocarcinoma.

Methods

From the nationwide Netherlands Cancer Registry, we selected patients with synchronous or metachronous metastatic esophagogastric adenocarcinoma. Patients with synchronous metastases diagnosed in 2015-2017 and patients with metachronous metastases who had received treatment with curative intent in 2015-2016 were available for analysis. TTF and OS were assessed by Kaplan-Meier methods and multivariable Cox regression.

Results

We identified 3311 patients with synchronous and 792 with metachronous metastases. Patients with synchronous metastases had higher median age (69 vs 66 years; p<0.01) and median BMI (24.9 vs 22.9 kg/m^2; p<0.01) compared to patient with metachronous metastases and a greater proportion received first-line systemic treatment (43% vs 33%; p<0.01). Patients with synchronous metastases had poorer survival outcomes compared to patients with metachronous metastases (median OS: univariate 4.2 vs 3.4 months, p=0.06; adjusted HR 1.12, 95% CI 1.02-1.22). Patients with synchronous metastases more often received EOX/ECC (15% vs 6%) and less often CapOx/FOLFOX (47% vs 54%) compared to patients with metachronous metastases. Between patients with synchronous and metachronous metastases treated with first-line systemic treatment, no significant differences were observed in median TTF of first-line or OS (TTF: univariate 5.3 vs 5.0 months, p=0.73; adjusted HR 1.05, 95% CI 0.89-1.23; OS: univariate 7.6 vs 7.1 months, p=0.28; adjusted HR 0.98, 95% CI 0.84-1.15).

Conclusions

Although patients diagnosed with synchronous metastases had a slightly worse survival than those with metachronous metastases, no differences in survival were observed between the two groups for patients receiving first-line systemic treatment.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Netherlands Comprehensive Cancer Organisation (IKNL).

Funding

Bristol-Myers Squibb.

Disclosure

D. Bertwistle: Shareholder/Stockholder/Stock options, Full/Part-time employment: BMS; Shareholder/Stockholder/Stock options: GSK; Shareholder/Stockholder/Stock options: Eli Lilly; Shareholder/Stockholder/Stock options: United Health; Licensing/Royalties: St Jude Children's Research Hospital. L. McDonald: Shareholder/Stockholder/Stock options, Full/Part-time employment: Bristol-Myers Squibb. H.W.M. van Laarhoven: Advisory/Consultancy: Bristol-Myers Squibb; Advisory/Consultancy: Lilly; Advisory/Consultancy: MSD; Advisory/Consultancy: Nordic Pharma; Advisory/Consultancy: Novartis; Advisory/Consultancy: Servier; Research grant/Funding (institution): Bayer; Research grant/Funding (institution): Bristol-Myers Squibb; Research grant/Funding (institution): Celgene; Research grant/Funding (institution): Janssen; Research grant/Funding (institution): Lilly; Research grant/Funding (institution): Nordic Pharma; Research grant/Funding (institution): Philips; Research grant/Funding (institution): Roche; Research grant/Funding (institution): Servier. R.H. Verhoeven: Research grant/Funding (institution): Bristol-Myers Squibb; Research grant/Funding (institution): Roch. All other authors have declared no conflicts of interest.