A potential paradigm shift that could in the longer term change the way we treat cancer and benefit millions of patients all over the world.

According to Claus Lindbjerg Andersen, professor at Aarhus University, this is the perspective in a new screening method that can identify cancer DNA in the blood, so that treatment can be initiated far earlier than is the case today.

Claus Lindbjerg Andersen is heading a major research project which has examined the use of the method on patients with bowel cancer.

And the study, which has just been published in the prestigious European Journal of Cancer, shows very promising results, says Claus Lindbjerg Andersen.

"This will change practice, and in the longer term it will change how we treat cancer."

Provides new perspectives

He bases his optimism on the study of 96 patients who have all been treated for so-called colorectal liver metastasis. In other words, bowel cancer that has spread to the liver.

This group of patients has a high risk of relapses, and a poor prognosis for survival. Thus, just 28 percent of the patients are alive five years after the diagnosis.

The high mortality is, among other things, due to the fact that the existing follow-up programme is not effective and quick enough to identify residual disease after either surgery or chemotherapy.

But a new technique has now made it possible to show whether a patient has tumour DNA in the blood, which is a clear marker for the presence of cancer cells somewhere in the body. And this opens up completely new opportunities for following up on patients with a high risk of suffering relapses.

"We can now examine a blood sample immediately after an operation or chemotherapy and in this way find out whether the patient has tumour DNA in the blood. And if that’s the case, then we know you need to begin further treatment. This provides some completely new perspectives and opportunities," explains Claus Lindbjerg Andersen.

Effective tool for monitoring patients

Current practice is to use CT scans and measurements of protein in the blood to find out whether there are residual diseases after an operation for colorectal liver metastasis.

However, none of the methods are particularly well-suited to an aggressive type of cancer, explains Claus Lindbjerg Andersen.

"Diagnostic imaging often gives an inconclusive answer. Therefore, you have to carry out more scans, but this means more time passes before a diagnosis is made and treatment begins. We’ve therefore lacked a marker that can show whether the operation or chemotherapy has worked and a tool that can determine how we should monitor the patients. This is the marker we’ve now found."

Every fourth patient in the study received one or more inconclusive scans after an operation or chemotherapy. The researchers have demonstrated that on average, three and a half months pass before treatment is initiated for these patients. Even after a conclusive scan, around a month passes before the treatment is initiated.

This is the time that could be won by measuring ctDNA.

"If there is tumour DNA in the blood, the patient will also suffer relapses, and with this method you’ll be able to begin treatment immediately," explains Claus Lindbjerg Andersen.

A matter of life and death

A few months may be vital. For patients with a fast-growing tumour, the level of cancer DNA increases dramatically up to the point in time when a relapse is confirmed.

"There is a doubling in the first month, and after three months, the amount of cancer has increased eight-fold, which is by definition bad news for the patient. That will be a matter of life or death for many of these patients," says Claus Lindbjerg Andersen.

In addition to previous treatment, the ctDNA measurements also provide an opportunity to enable a large group of patients with a small risk of relapses to avoid unnecessarily intensive follow-up.

ctDNA measurements make it possible to divide the patients into two groups, one with a high risk and another with a low risk of relapses.

"This will make it possible to organise individualised follow-up for patients. In this way, we also ensure better utilisation of resources, because we can concentrate our efforts on those with a high risk of relapse," explains Claus Lindbjerg Andersen.

Can be used for almost all types of cancer

While it will in future be possible to identify the most serious cancer cases, there is still a lack of effective treatment options for patients with colorectal liver metastasis. However, with early detection, any follow-up treatment will, all things being equal, have better chances of working.

And the perspectives for the use of ctDNA measurements are almost endless, explains Claus Lindbjerg Andersen.

"It will be possible to use this method for all types of cancer that release DNA into circulation in the blood, which is virtually all of them. We’re already working on setting up studies for other types of cancer."

Further information

Claus Lindbjerg Andersen, professor at Aarhus University and director of DCCC National Danish ctDNA research Center 

Phone: +4529804321

Mail: cla@clin.au.dk