Thromboprophylaxis in oesophageal cancer patients-a study protocol for a randomised, controlled trial (TOP-RCT).

Background: The purpose of the study is to examine if prolonged thromboprophylaxis decreases the risk of thrombosis after intended curative surgery for oesophageal cancer. Study results are expected to inform a guideline for thromboprophylaxis after oesophageal cancer surgery. The perspective is to reduce morbidity and mortality in this critically ill patient group. Thrombosis is the second-most common cause of cancer death after the cancer itself. The risk of thrombosis depends on the cancer type, and upper gastrointestinal cancers are considered high risk. This risk is further increased when patients undergo surgery. However, only few studies have investigated the peri- and postoperative coagulation profile in oesophageal cancer patients. Due to this lack of knowledge, prophylaxis is currently restricted to 5000 IU (international units) low-molecular weight heparin daily from surgery until discharge from hospital (approximately 10 days), whereas patients with gastric cancer receive 30 days of treatment. The present study examines whether a 30-day treatment is superior and safe, compared with the current standard treatment.

Methods: The study is a randomised controlled trial. Inclusion is ongoing, and we aim to include 100 patients. Blood samples are drawn before and after surgery, and the coagulation is extensively examined. The primary endpoint is the difference in plasma levels of prothrombin fragment 1 + 2 (F1 + 2) 30 days after surgery between the intervention and the standard group. Furthermore, patients are examined with ultrasound to screen for asymptomatic venous thrombotic events (VTE). Secondary endpoints are incidence of bleeding, symptomatic and asymptomatic VTE and mortality 30 days 1 one year after surgery.

Discussion: The study will provide valuable information on the perioperative coagulation profile and VTE risk of oesophageal cancer patients. The study seeks to aid in optimising the postoperative thromboprophylaxis, and the perspective is to reduce morbidity and mortality in this at-risk patient population.

Trials Registration: The trial was prospectively registered at the EU Clinical Trials Register with ID 2021-001335-24 on 30 June 2021 and at ClinicalTrials.gov with study identifier NCT05067153.