‘Magnetised’ molecules reveal greater detail of breast cancer
Image credit: Shao-chun Wang - Dreamstime
A new scan that involves magnetising molecules allows doctors to see in real-time which regions of a breast tumour are active, recent research suggests.
The researchers, based at the Cancer Research UK Cambridge Institute and the Department of Radiology, University of Cambridge, said it is the first time they have demonstrated that this scanning technique – called carbon-13 hyperpolarised imaging – can be used to monitor breast cancer.
The technique was tested on seven patients from Addenbrooke’s Hospital with various types and grades of breast cancer before they had received any treatment.
As part of the study, the team used the scan to measure how fast the patients’ tumours were metabolising a naturally occurring molecule called pyruvate and were able to detect differences in the size, type and grade of tumours – a measure of how fast-growing, or aggressive, the cancer is.
The scan also revealed in more detail the ‘topography’ of the tumour, detecting variations in metabolism between different regions of the same tumour.
Patients are injected with the magnetised molecules before getting an MRI scan
Image credit: Cancer Research UK
“This is one of the most detailed pictures of the metabolism of a patient’s breast cancer that we’ve ever been able to achieve. It’s like we can see the tumour ‘breathing’,” said Professor Kevin Brindle, lead researcher from the Cancer Research UK Cambridge Institute.
“Combining this with advances in genetic testing, this scan could in the future allow doctors to better tailor treatments to each individual, and detect whether patients are responding to treatments, like chemotherapy, earlier than is currently possible”.
Hyperpolarised carbon-13 pyruvate is an isotope-labelled form of the molecule that is slightly heavier than the naturally occurring pyruvate which is formed in our bodies from the breakdown of glucose and other sugars.
As part of the study, the team ‘hyperpolarised’, or magnetised, carbon-13 pyruvate by cooling it to about one degree above absolute zero (-272°C) and exposing it to extremely strong magnetic fields and microwave radiation.
The frozen material was then thawed and dissolved into an injectable solution. Following this, the patients at Addenbrooke’s were injected with the solution and then received an MRI scan at the hospital.
A naturally-occurring chemical called pyruvate is made 10,000 times more magnetic than usual by chilling it to -272°C (-457°F) but it only stays that way for a very short period of time
Image credit: Cancer Research UK
According to the study, magnetising the carbon-13 pyruvate molecules increases the signal strength by 10,000 times so they are visible on the scan. And using the scan, they measured how fast pyruvate was being converted into a substance called lactate.
Cells convert pyruvate into lactate as part of the metabolic processes that produce energy and the building blocks for making new cells. Tumours, on the other hand, have a different metabolism from healthy cells and so produce lactate more quickly. This rate also varies between tumours, and between different regions of the same tumour.
The study showed that monitoring this conversion in real time could be used to infer the type and aggressiveness of the breast cancer, with the team hoping to trial this technique in larger groups of patients, to see if it can be reliably used to inform treatment decisions in hospitals.
“This exciting advance in scanning technology could provide new information about the metabolic status of each patient’s tumour upon diagnosis, which could help doctors to identify the best course of treatment,” said Professor Charles Swanton, Cancer Research UK’s chief clinician.
“And the simple, non-invasive scan could be repeated periodically during treatment, providing an indication of whether the treatment is working. Ultimately, the hope is that scans like this could help doctors decide to switch to a more intensive treatment if needed, or even reduce the treatment dose, sparing people unnecessary side effects.”
The molecules are injected using this machine
Image credit: Cancer Research UK
Breast cancer is the most common type of cancer in the UK and has around 55,000 new cases each year. 80 per cent of people with breast cancer survive for 10 years or more; however, for some subtypes, survival is much lower.
Using the magnetic scan, scientists will be able to tell how fast someone's tumour is growing and therefore work out how urgently it needs to be treated. Furthermore, understanding the internal workings of a tumour could help doctors make treatments extra-precise and avoid patients being under- or over-treated.
Anatomic image of a breast tumour (left), MRI scan showing the pyruvate signal (centre) and lactate signal (right)
Image credit: Cancer Research UK
Earlier this month, an AI programme proved as effective as expert radiologists at detecting breast cancer based on screening mammograms and showed promise of reducing errors.
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