Abstract 1431P
Background
Gastric cancer (GC) is the third leading cause of cancer worldwide. Clinical and molecular heterogeneity of GC is broadly recognized. TCGA divides GC in four subtypes; Epstein-Barr virus (EBV) positive, MSI, genomically stable, and chromosomal instability. We aimed to better characterize the MSI pts in our cohort by comparing them to the MSS pts and explore prognostic factors in GC pts.
Methods
A review of the retrospective Vall d’Hebron University Hospital EURECCA database of all pts who underwent gastric surgery between 2014 and 2018 was conducted. We analysed clinical and tumour characteristics with immunohistochemistry (IHQ) and studied predictors of mortality across all pts affected by GC. Descriptive and univariate analysis were performed to detect differences between MSI and MSS groups. OS was calculated with the Kaplan-Meier method and univariate Cox models were fitted to estimate hazard ratios with CI95%.
Results
Among all pts who underwent surgery, 134 (92%) were primary GC and 12 (8%) were gastroesophageal junction. Twelve pts (13%) were MSI, 80 pts (87%) MSS, 41 pts (29%) Her2 positive, and four pts (4.4%) EBV. Comparing MSI vs MSS groups, median age was 80 (IRQ 71.2 – 86) vs 70 years (IRQ 62.7 – 78) [p=0.013], 50% vs 27% were women [p=0.17], and 83% vs 50.7% were intestinal histological subtype [p=0.035]. Neoadjuvant chemotherapy was administered in two MSI pts (16.7%), one received adjuvant chemotherapy and nine (75%) surgery alone. With a median follow-up of 49.9 months (m) (IQR 25.7 – 52.5), the MSI median OS was not reached and those with MSS status had a median OS of 70.6m. In the entire cohort, pts with BMI>25 had a 3-year OS of 81.8m vs 51.7m in pts with BMI<25, patients with T≤2 had a median OS of 85.9m vs 42.7m in the ≥T3 group [p<0.001], and patients with negative nodes had a median OS of 81.8m vs 49.3m in the node positive group [p=0.030].
Conclusions
In our cohort, MSI status was detected in 13% of pts by IHQ. In this subgroup most were elderly pts, intestinal histology and presented a better OS than MSS status. In the overall population of GC pts, increased BMI played a positive role in OS and factors linked to disease aggressiveness related to worse OS.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
VHIO.
Funding
Has not received any funding.
Disclosure
O. Mirallas: Financial Interests, Personal, Invited Speaker: ROVI; Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Personal, Invited Speaker: Kyowa Kirin; Financial Interests, Personal, Invited Speaker: Grupo Pacifico; Other, Other, Travel Expenses: Kyowa kirin; Other, Other, Travel Expenses and Conference Fee: Sanofi. J. Tabernero: Financial Interests, Personal, Advisory Board: Array Biopharma; Financial Interests, Personal, Advisory Board: AstraZeneca; Financial Interests, Personal, Advisory Board: Avvinity; Financial Interests, Personal, Advisory Board: Bayer; Financial Interests, Personal, Advisory Board: Boehringer Ingelheim; Financial Interests, Personal, Advisory Board: Chugai; Financial Interests, Personal, Advisory Board: Daiichi Sankyo; Financial Interests, Personal, Advisory Board: F.Hoffman-La Roche; Financial Interests, Personal, Advisory Board: Genetech Inc; Financial Interests, Personal, Advisory Board: HalioDX SAS; Financial Interests, Personal, Advisory Board: Hutchinson MedPharma International; Financial Interests, Personal, Advisory Board: Ikena Oncology; Financial Interests, Personal, Advisory Board: IQVIA; Financial Interests, Personal, Advisory Board: Lilly; Financial Interests, Personal, Advisory Board: Menarini; Financial Interests, Personal, Advisory Board: Merck Serono; Financial Interests, Personal, Advisory Board: Merus; Financial Interests, Personal, Advisory Board: MSD; Financial Interests, Personal, Advisory Board: Neophore. M. Diez: Financial Interests, Personal, Speaker’s Bureau: Lilly. T. Macarulla Mercade: Financial Interests, Personal, Advisory Role: Ability Pharma; Financial Interests, Personal, Advisory Role: Advance Medical HCMS; Financial Interests, Personal, Advisory Role: Batxer; Financial Interests, Personal, Advisory Role: BioLineRX; Financial Interests, Personal, Advisory Role: Celgene SLU; Financial Interests, Personal, Advisory Role: EISAI; Financial Interests, Personal, Advisory Role: Genzyme; Financial Interests, Personal, Advisory Role: Incyte; Financial Interests, Personal, Advisory Role: Ipsen Pharma Lab; Financial Interests, Personal, Advisory Role: Lilly; Financial Interests, Personal, Advisory Role: Merck; Financial Interests, Personal, Advisory Role: Sharp and Dhome; Financial Interests, Personal, Advisory Role: QED Therapeutics; Financial Interests, Personal, Advisory Board: Roche; Financial Interests, Personal, Advisory Role: Sanofi-Aventis; Financial Interests, Institutional, Funding: Agios; Financial Interests, Institutional, Funding: Aslan; Financial Interests, Institutional, Funding: AstraZeneca; Financial Interests, Institutional, Funding: Bayer; Financial Interests, Institutional, Funding: Celgene; Financial Interests, Institutional, Funding: Genetech; Financial Interests, Institutional, Funding: Hallozyme; Financial Interests, Institutional, Funding: Immunomedics; Financial Interests, Institutional, Funding: Lilly; Financial Interests, Institutional, Funding: Merimarck; Financial Interests, Institutional, Funding: Millenim; Financial Interests, Institutional, Funding: Novartis; Financial Interests, Institutional, Funding: Pfizer; Financial Interests, Institutional, Funding: Roche. All other authors have declared no conflicts of interest.