A type of breast cancer treatment which only works on certain patients is being misused by doctors, according to a new study.
The drug trastuzumab (Herceptin) should be used to combat breast cancer which shows evidence of the HER2 protein as it will otherwise be ineffective, said the authors, but this research shows that doctors are not testing for the protein enough.
Results of the study, carried out by the University of California-San Francisco Center for Translational and Policy Research on Personalized Medicine, indicate that around one in five breast cancer patients given trastuzumab have no evidence of an HER2 test.
Dr Elena Elkin, one of the study's co-authors, commented: "Our review of the literature suggests that there are important knowledge gaps regarding the real-world use of HER2 testing and trastuzumab."
A recent study showed that depression can worsen a patient's chances of surviving cancer, although it was also pointed out that patients should not feel like they have to constantly be in a happy mood to resist the illness.