NHS organisations are not being checked to see whether they are adhering to "best practice" guidance issued by health regulators, a charity has warned.
Breast Cancer Campaign warned that the care of breast cancer patients is being " threatened by inadequate monitoring and reporting" of whether or not NHS bodies are implementing the guidance.
The National Institute for Health and Care Excellence (Nice) issued a breast cancer quality standard in 2011 setting out what high quality care for patients should look like.
But a new report from the charity said that the standard is not being used to its full potential because there is no monitoring or reporting on performance of it.
The charity called on NHS England to publish an annual review of compliance with Nice's breast cancer quality standard.
"Attempts to monitor the breast cancer quality standards are virtually non-existent," said Breast Cancer Campaign chief executive Baroness Delyth Morgan.
"It's not enough to pay lip-service to standards of care and consider that job done. There is an urgent need to ensure that appropriate levers and incentives are in place to deliver these improved standards of care.
"The breast cancer quality standard is a vital tool which if we harness to its full potential, will help greatly to improve the standards of care in a rapidly changing NHS that all women living with breast cancer deserve. Women living with breast cancer face many challenges, but poor-quality care should not be one of them."
Professor Gillian Leng, director of health and social care at Nice, said: " Nice guidance has already helped to raise the quality of care for people with breast cancer. This report from Breast Cancer Campaign highlights there is still more to do.
"Nice has systems in place to support the implementation of our guidance and quality standards. We are working with the Care Quality Commission to ensure their monitoring processes and systems take account of our recommendations.
"We will continue to work with NHS England to review the uptake of our quality standards and support them in raising the standards of all NHS services through the commissioning process."
Sean Duffy, national clinical director for cancer at NHS England, added: "We want world class cancer services for all patients and all cancers. What we know is that although we have made great strides over recent years, quality varies between cancers and across the country.
"That is why it is so important that providers and commissioners of services ensure that care reflects the quality standards set out by the Nice. These standards are based on evidence guidelines and serve as the best advice for the delivery of high quality care. We will continue to champion this with providers and commissioners."