How the CRCTU is addressing overtreatment of ductal carcinoma in situ (DCIS)

Miss Claire Gaunt

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The NHS Breast Screening Programme was established in the late 1980’s with the aim of detecting invasive disease at an early stage and reducing deaths from breast cancer. This has been achieved but, an incidental consequence has been the increasingly common finding of DCIS, a diagnosis almost unheard of before mammographic imaging. Historically, DCIS was thought of as a form of early breast cancer that would become an invasive breast cancer if left untreated.

DCIS describes abnormal cells in the milk ducts of the breast. It is divided into 3 types; low, intermediate and high grade. Low grade DCIS looks similar to normal breast cells and high grade DCIS looks similar to cancer cells. When diagnosed, all DCIS is currently removed by surgery because of concern that it may progress to an invasive cancer. If DCIS is indeed an early form of breast cancer, then removing it would have lead to a decrease in the incidence of invasive breast cancer. This has not been the case but, surgical treatment of DCIS, often mastectomy, has remained unchanged since the 1950’s, despite evidence that removing DCIS does not prevent invasive cancers. DCIS is almost always diagnosed as a result of calcification found on mammograms and accounts for 20% of all breast ‘cancers.’ Evidence shows that many women are being treated for a condition that will never become a clinical problem if left undiagnosed. This is known as ‘overdiagnosis’ and ‘overtreatment’. Experts agree that not all untreated DCIS will become breast cancer.

An independent review of the UK National Health Service Breast Screening Programme reported on the benefits and harms of breast screening. This concluded that breast screening saves lives but acknowledged the existence of overtreatment. Consequently, randomised trials were recommended to elucidate the appropriate treatment of screen-detected DCIS and to gain a better understanding of its natural history. The aim of overtreatment trials is to stop treating women who do not need treatment and to better treat those who do.

The Low Risk DCIS Trial (LORIS) is a large phase 3 trial designed to address the recognised issue of overtreatment of low risk DCIS. This trial is not for patients with high grade (the most common) DCIS.

The study is being run by the Cancer Research UK Clinical Trials Unit (CRCTU) which has a long history of running successful breast cancer treatment trials and is an integral part of the Birmingham Surgical Trials Consortium (BiSTC) at the University of Birmingham. The trial is led by Miss Adele Francis, Consultant Surgeon at the University Hospitals Birmingham NHS Foundation Trust. The trial will recruit almost a 1000 women with low risk DCIS, who will be randomised to the current standard treatment which is surgery or to omit surgery and have active monitoring with annual mammograms. The LORIS trial, through it’s clinical and translational research will establish whether patients with newly diagnosed low risk DCIS can safely avoid surgery without detriment to their wellbeing (both psychological and physical) and whether those patients who do require surgery can be identified by pathological and radiological means. When this trial is reported, patients and clinicians will be able to make an informed choice about treatment options.

University Hospitals Birmingham NHS Foundation Trust will be the first centre to begin recruit patients in to this ground-breaking trial. In the coming months, you can follow our progress on twitter at @CRCTU

Miss Claire Gaunt is a Team Leader in the Cancer Research UK Clinical Trials Unit at the University of Birmingham.

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