Over a third of breast cancer tumours change form when they spread, researchers at the University of Edinburgh have found.

The research, undertaken in the university's Breakthrough Breast Cancer Unit, could change the kinds of tests and treatments patients are given at a clinical level.

“These are exciting findings,” head researcher Dr Dana Faratian told The Journal.

“What they indicate is that performing the same or similar tests that pathologists already perform on the primary tumour—that is, the tumour in the breast—on the spread tumour—the tumour in the lymph node—can better guide therapy for each individual patient,” Dr Faratian said.

The team studied 385 patients of which 211 had tumours that had spread from the breast to the lymph nodes.

They used a unique type of image analysis to compare the three markers most commonly used in breast cancer diagnosis and treatment.

Scientists were surprised to find that as many as 39 percent of tumours that spread to the lymph nodes alter their organic behaviour.

There are clinical implications for the findings, as Dr Faratian explained: “We know that when tumour has spread to lymph nodes a woman tends to have a poorer prognosis than if the tumour is confined to the breast. Therefore, we give other therapies, such as chemotherapy, to these women to try to get rid of the disease.”

The research helps explain certain instances of treatment failure. If a primary tumour is receptive to hormone treatments there is a chance that the spread tumour is not.

There are plans to test these results in phase three clinical trials. These trials would establish whether or not different treatment programmes for primary and spread tumours increase the chance of recovery.

Should these trials prove successful, the findings would be implemented in NHS treatment programmes for breast cancer.