New breast cancer treatment cuts recurrence by 25%, study shows

A new treatment for patients with a common type of breast cancer has cut the risk of recurrence by a quarter, a new study has shown.

Patients with hormone receptor positive (HR+) early stage breast cancer at a high risk of recurrence were recruited to the global randomised study led by the Royal Marsden NHS Foundation Trust.

The phase three monarchE study, with 5,637 patients in 38 countries, has been described as “one of the most promising breakthroughs for patients with this type of breast cancer in the last 20 years”, the institution said.

It tested if patients taking the CDK 4/6 inhibitor abemaciclib along with hormone therapy following standard of care treatments such as chemotherapy, surgery and/or radiotherapy would reduce the risk of recurrence compared with the standard hormone treatment alone.

Over two years, it found a 25% reduction in recurrence of cancer when abemaciclib was added to the standard hormone therapy compared with hormone therapy alone.

Some 11.3% of patients in the control group suffered a relapse of their cancer compared with 7.8% of those in the abemaciclib group, Royal Marsden said.

Around 70% of breast cancer patients have hormone receptor positive tumours, and a proportion of those have a higher risk of relapse in the first two years, it added.

“Patients with disease that has spread to lymph nodes, a large tumour size at the time of diagnosis, or an increased cellular proliferation (determined by high grade of the tumour, or number of dividing cells) were considered to be at ‘high risk’ of recurrence and recruited to the study” Royal Marsden said.

Study patient Sarah Ryder, 57, from Dorset, said she “did not feel much hope” after finding out her cancer had spread to 23 lymph nodes when she was referred last year.

She said: “The trial has helped me believe in a future again. I can see my daughter grow up, go off to university next year and maybe have a family of her own one day.”

The monarchE research has given us confidence that we will soon be able to offer our high risk HR+ patients a greater chance of keeping them cancer-free

Professor Stephen Johnston, consultant medical oncologist at the Royal Marsden and professor of breast cancer medicine at the Institute of Cancer Research, said: “This research could potentially save many lives in the future.”

He said: “The monarchE research has given us confidence that we will soon be able to offer our high risk HR+ patients a greater chance of keeping them cancer-free.

“While there have been many advances in other early breast cancer subtypes such as HER2 positive disease, there has been no significant advancements for the large group of patients who have hormone receptor positive breast cancer since the late 1990s when aromatase inhibitors were introduced.

The results of the monarchE study are being presented at the European Society for Medical Oncology Virtual Congress on Sunday evening and simultaneously published in the Journal of Clinical Oncology.

The monarchE trial was funded by Eli Lilly pharmaceutical.