Aspirin as secondary prevention in colorectal cancer liver metastasis (ASAC trial): study protocol for a multicentre randomized placebo-controlled trial

Trials. 2021 Sep 20;22(1):642. doi: 10.1186/s13063-021-05587-w.


Background: Colorectal cancer is one the most common cancers in the western world with increasing incidence. Approximately 50% of the patients develop liver metastases. Resection of liver metastases is the treatment of choice although almost half of the resected patients get recurrence in the liver.

Methods: The ASAC trial is a Scandinavian, multicentre, double-blinded, randomized, placebo-controlled study to determine whether adjuvant treatment with low-dose aspirin (acetylsalicylic acid (ASA)) can improve disease-free survival in patients treated for colorectal cancer liver metastases (CRCLM). Up to 800 patients operated for CRCLM will be randomized to Arm#1 ASA 160 mg once daily or Arm#2 Placebo, for a period of 3 years or until disease recurrence. The patients will be recruited at all major hepatobiliary surgical units in Norway, Sweden and Denmark and have follow-up according to standard of care and the National Guidelines.

Discussion: The ASAC trial will be the first clinical interventional trial to assess the potential beneficial role of ASA in recurrence of CRCLM and survival. ASA is an inexpensive, well-tolerated and easily accessible drug that will be highly potential as adjuvant drug in secondary prevention of CRCLM if the study shows a beneficial effect. We will also determine the effect of ASA as adjuvant treatment on Health-Related Quality of Life and the cost-effectiveness.

Trial registration: NCT03326791 . Registered on 31 October 2017.

Keywords: Acetylsalicylic acid; Aspirin; Colorectal cancer; Liver metastases; Secondary prevention.

Publication types

  • Clinical Trial Protocol

MeSH terms

  • Aspirin / adverse effects
  • Colorectal Neoplasms* / prevention & control
  • Double-Blind Method
  • Humans
  • Liver Neoplasms* / drug therapy
  • Liver Neoplasms* / prevention & control
  • Multicenter Studies as Topic
  • Neoplasm Recurrence, Local / prevention & control
  • Quality of Life
  • Randomized Controlled Trials as Topic
  • Secondary Prevention


  • Aspirin

Associated data