New research from Aarhus University Hospital and Aarhus University shows that a blood sample can predict the risk of recurrence in patients treated for colorectal cancer.

Two-thirds of all patients with colorectal cancer undergo curative surgery; however, 25-30% of the patients experience recurrence of cancer.

This made researchers from Aarhus University Hospital and Aarhus University start a research project examining blood samples from patients surgically treated for cancer. The results of the research have just been published in the acknowledged scientific journal JAMA Oncology.


DNA fragments in the blood

The blood samples were analysed to find small fragments of DNA originating from cancer cells, which can reveal if the patient still has cancer cells present in the body.

A total of 130 patients have been included in the study since 2014. Regular blood samples have been drawn every third month for a period of three years after the operation.

- Our results are very promising and show that if a patient has cancer DNA in the blood after surgery, the risk of recurrence is very high – close to 100%, says Claus Lindbjerg Andersen, Professor at Department of Molecular Medicine at Aarhus University Hospital.

- Cancer DNA in the blood is a much better indicator of the risk of recurrence than the risk factors used today.

The results also show that analyzing serial blood samples makes it possible to detect recurrence approximately nine months before the cancer is detectable by CT.

- Potentially, this is of major importance to patient treatment; the sooner a recurrence is detected, the more treatment options are available.


New study has already been started

Due to the promising results, researchers have already started a new large study including 1,800 patients, who will have regular blood samples collected after cancer surgery. If cancer DNA is detected in their blood, indicating a high risk of recurrence, the patients will be offered intensive follow-up with CT or chemotherapy with intensive follow-up.

- The goal is to find the most efficient treatment for patients with cancer DNA in the blood, says Claus Lindbjerg Andersen.

- We would like to demonstrate that the individualised and personal follow-up by blood sample analyses gives better results for the individual patient but it is also an optimal use of healthcare resources.

Claus Lindbjerg Andersen expects that results from the new study will be ready in 3-5 years. If results are as expected, regular blood sample analyses will be a part of standard cancer treatment.


FACTS on cancer DNA in the blood:

  • In both healthy and diseased individuals, the cells in the body, including cancer cells, release small fragments of DNA in the blood
  • This means that patients with cancer, opposite healthy persons, have DNA with cancer mutations in their blood
  • The test maps out the small fragments of DNA, floating in our blood and determines if some of the fragments have mutated. If mutations are detected, it is a sign of cancer
  • The test does not cover the entire genome, but only a part of it where cancer cells are often mutated.


Behind the research result:

Study type: Observational prospective cohort study among Danish patients with colorectal cancer.

Collaborators: Department of Molecular Medicine, Department of Surgery, Department of Pathology – Aarhus University Hospital. Department of Clinical Medicine, Aarhus University. Department of Surgery, Department of Pathology, Regional Hospital Randers. Department of Surgery, Department of Pathology, Regional Hospital Herning (Regional Hospital West Jutland) and Natera Inc., USA.

External financing: Danish Cancer Society, Novo Nordisk Foundation, The Danish Council for Strategic Research, Independent Research Fund Denmark.

Publicering: Peer-reviewed article in the American Journal of the American Medical Association Oncology (JAMA Oncology).

Conflicts of interest: None.


Read the scientific article:


Further information:

Claus Lindbjerg Andersen, Professor, Department of Molecular Medicine, Aarhus University Hospital, Tel.:+45 78 45 53 19, e-mail: cla@clin.au.dk