Incidence and prognostic role of venous thromboembolism in gastric cancer: a nationwide Finnish register study.

[BACKGROUND] Gastric cancer (GC) is associated with a high risk of venous thromboembolism (VTE). We investigated the incidence of VTE before and after a GC diagnosis and its association with overall survival (OS).

[METHODS] We identified GC patients diagnosed in 2011-2016 from the Finnish Cancer Registry, and collected data on healthcare visits, death, and follow-up through the end of 2020. We compared patients based on their cancer stage and the type of treatment they received.

[RESULTS] We identified 3023 GC patients, amongst whom 995 (32.9 %) underwent gastric surgery, 134 (4.4 %) explorative surgery, and 1894 (62.7 %) no surgery for GC. The cumulative incidence of VTE at 12 and 24 months following GC diagnosis was 5.1 % [95 % confidence interval (CI) 4.31-5.89] and 5.8 % (95 % CI 4.97-6.63), respectively. VTE within one year before GC diagnosis was significantly more frequent amongst no surgery (1.9 %) patients than amongst the gastric (0.8 %) or exploratory surgery only (0.7 %) subgroups (p = 0.018). Median OS amongst patients who had a VTE within one year before a GC diagnosis was 4 months compared to 10 months amongst those who did not (p = 0.001). VTE similarly associated with a worse prognosis, whether occurring within one year before [hazard ratio (HR) 1.69] or after (HR 1.78) a GC diagnosis.

[CONCLUSIONS] VTE associated with a worse survival, whether occurring before or after a GC diagnosis. Pre-diagnosis VTE associated with a lower likelihood of curative-intent surgery presumably due to more advanced GC or VTE-related treatment interference.