The risk of venous thromboembolism after surgery for esophagogastric malignancy and the impact of chemotherapy: a population-based cohort study.

To define the incidence of postoperative venous thromboembolism (VTE) and effects of chemotherapy in a population undergoing surgery for esophagogastric cancer. This population-based cohort study used linked primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care data from England to identify subjects undergoing esophageal or gastric cancer surgery between 1997 and 2014. Exposures included age, comorbidity, smoking, body mass index, and chemotherapy. Crude rates and adjusted hazard ratios (HRs) were calculated for rate of first postoperative VTE using Cox regression models. The cumulative incidence of VTE at 1 and 6 months was estimated accounting for the competing risk of death from any cause. Of the 2,452 patients identified, 1,012 underwent gastrectomy (41.3%) and 1,440 esophagectomy (58.7%). Risk of VTE was highest in the first month, with absolute VTE rates of 114 per 1,000 person-years (95% CI 59.32-219.10) following gastrectomy and 172.73 per 1,000 person-years (95% CI 111.44-267.74) following esophagectomy. Neoadjuvant and adjuvant chemotherapy was associated with a six-fold increased risk of VTE following gastrectomy, HR 6.19 (95% CI 2.49-15.38). Cumulative incidence estimates of VTE at 6 months following gastrectomy in patients receiving no chemotherapy was 1.90% and esophagectomy 2.21%. However, in those receiving both neoadjuvant and adjuvant chemotherapy, cumulative incidence following gastrectomy was 10.47% and esophagectomy, 3.9%. VTE rates are especially high in the first month following surgery for esophageal and gastric cancer. The cumulative incidence of VTE at 6 months is highest in patients treated with chemotherapy. In this category of patients, targeted VTE prophylaxis may prove beneficial during chemotherapy treatment.