Scientists have developed a new pill that can improve breast cancer screening by lighting up tumours and help doctors better distinguish between cancerous and benign growths. An issue with current breast cancer screening methods is that they often identify lumps but cannot conclusively pinpoint which ones are cancerous.
“Screening can potentially catch the disease early in some patients, but false positives can lead to unnecessary, aggressive treatments in patients who don’t need them,” said Greg Thurber, assistant professor at University of Michigan.
Breast cancer is the second most common cancer in women. Mammograms, the current standard for screening, are X-rays of breast tissue. They give doctors information about a lump’s location and size, but they can not distinguish between cancerous and benign growths. To find out more, doctors take biopsies, which involve needles or surgery and are not 100 per cent conclusive.
When suspicious lumps are found, doctors and patients will often opt for treatment ranging from surgery to radiation or chemotherapy, which can take months and cause serious side effects.
To better weed out patients who do not really need treatment, the researchers developed the oral pill containing an imaging agent that selectively binds to cancer cells or blood vessels that are unique to tumours.
Once attached to its target, the dye fluoresces under near-infrared light.
Although at this wavelength, fluorescent tumours can only be detected 1 to 2 centimetres deep, pairing the technique with ultrasound in the same instrument should be able to detect most cancers, Thurber said.
Testing in mice showed that with the proper formulation, a considerable proportion – 50 to 60 per cent – of the agent gets absorbed into the bloodstream.
It also binds specifically to cancer cells with little background noise in the image. The fluorescent signal from the tumour was far stronger than the signal from the surrounding tissue.
If the team succeeds in formulating the pill for human patients, Thurber said the high image contrast should bode well for women with dense breast tissue whose mammograms are difficult to read.