Genetic tests 'predict' which breast cancers will spread The researchers studied data from 427 patients with early breast cancer that had not spread. The Mammaprint test had been used by doctors to help them decide if women needed chemotherapy by predicting which patients are at low and which at high risk of secondary cancers. Dr Linn said: "It is encouraging to be able to tell patients that we believe they will have just as good a chance of avoiding the recurrence of cancer by not having adjuvant chemotherapy as by having it. Many patients dread the idea of chemotherapy, and by avoiding it they can substantially reduce the stress involved in having cancer, as well as improve their overall quality of life. The test has been improved so it can be conducted on standard samples of the tumour. Professor David Cameron, from the University of Edinburgh (Edinburgh, UK) and chairman of the conference said: "There is great interest in being able to tell a woman that she does not need chemotherapy because her chances of surviving breast cancer are not improved by being given it. There are several potential tests to help clinicians and patients make this decision, and the one discussed here has always looked promising, but previously needed a snap frozen tumour sample which was not available for every patient. That this is no longer necessary is an important step forward for patients. Another study presented at the conference found it was possible to predict which patients would suffer side effects from chemotherapy enabling doctors to choose the drugs most suitable. Dr Christof Vulsteke, from the Catholic University of Leuven, Belgium, examined DNA from blood samples from 1089 breast cancer patients who were treated between 2000 and 2010 with three commonly used chemotherapy drugs, fluorouracil, epirubicin and cyclophosphamide. They found one genetic variation that was linked to severe side effects. "Our research has brought us one step closer towards prescribing personalised chemotherapy treatment with a minimum of side effects," Dr Vulsteke said.