“The method has been tested on mice in which a human breast tumor is implanted,” said the research team’s lead scientist, Hadassa Degani, interviewed in Paris, where she is on sabbatical doing research at the Pasteur Institute.
“The information is very detailed and allows total diagnosis.”
The Israeli team reported its findings Thursday of last week in the journal Nature Medicine.
The method consists of injecting a contrasting agent, or dye, into the patient’s bloodstream, and using MRI to monitor how the dye moves into the tumor and is distributed through the tumor tissue — as well as how it is cleared out.
Monitoring the movement of the contrasting agent allows two important criteria to be measured: the vascularity, or porosity, of the blood vessels in the tumor, and the space between the cells.
Because these criteria tend to differ between benign and malignant tumors, monitoring them makes diagnosis possible.
For instance, in fibroadenoma, the most common type of benign breast tumor, the blood vessels that feed the tumor are fewer and less porous, and the space between the cells is greater, thus limiting the flow into the tumor cells of substances represented by the contrasting agent in the imaging.
On the contrary, the blood vessels in malignant tumors tend to be more numerous and very permeable, and the space between the cells smaller, allowing the substance that the tumor needs to grow to move in and be cleared out more freely.
Using MRI is also more effective than a needle biopsy in that it shows the entire tumor, which would otherwise require radical surgery, Degani said.
“It’s not painful; it’s not surgery,” said Degani, who was trained as a chemist but began doing breast cancer research in 1985.
“It would definitely help women psychologically if the type of cancer they have can be determined without a long wait for the result.”
Degani’s team of doctoral students at Weizmann and radiologists from Hebrew University-Hadassah Medical Center were able to use the method to diagnose breast tumors on 18 women, eight of whom had fibroadenoma and 10 of whom had malignant tumors.
“To what extent it would really reduce the number of biopsies and provide reliable prognosis has yet to be determined,” Degani said.
“A statistical study now has to be obtained with clinical trials. My goal now is to find the means to conduct clinical trials. My country is small,” she said, explaining that a larger sample population was necessary.
“Even if we can reduce by one half the number of biopsies, that would be a lot,” she added.
Degani said the method can be used on other organs, possibly even for brain tumors, and is being tested on kidney and liver transplants.