A study into the research and treatment of breast cancer has found barriers exist to improving patient care, including a lack of money.
Charity Breast Cancer Campaign said the research showed not enough is known about why treatments fail to help some patients with thousands of women dying each year from the disease.
And it said more needed to be done to tackle gaps in the research and treatment of breast cancer.
The research, published in the journal Breast Cancer Research, is thought to be one of the largest ever carried out.
Gaps existed across all the themes, including in the knowledge of how genetics influence cancer, how cancer spreads and recurs, prevention, and how the disease impacts psychologically and socially on patients from a range of ethnic and demographic backgrounds.
The study's authors said: "Gaps were identified in all seven themes. General barriers to progress were lack of financial and practical resources, and poor collaboration between disciplines."
The experts made several recommendations, including creating better models to predict and prevent the cancer, improving research trials and greater sharing of information among clinicians.
They also called for better methods to find out how and why breast cancer spreads to other parts of the body and to determine the effectiveness of treatment at an early stage.