A new treatment for breast cancer has been hailed a “game changer” after it was found to slow the progression of aggressive breast cancer by nine months. By combining an established hormone drug called fulvestrant with a new treatment called palbociclib, doctors found they could slow the cancer growth in around two thirds of women with advanced forms of the most common type of breast cancer, thereby delaying the need for chemotherapy.

The international study, which was carried out across 17 countries, followed 521 women who received either palbociclib and fulvestrant, or a dummy pill and fulvestrant. Women who took the new combination of drugs saw the progression of their cancer slow by an average of 9.5 months, compared with 4.6 months in the placebo group.

A total of 67 per cent of women in the group taking palbociclib plus fulvestrant either saw a reduction in the size of tumour or control of disease for at least six months. That was compared with 40 per cent of the women in the dummy pill group. One in five women even saw a decrease in tumour size, according to the study, which was published in the Lancet Oncology medical journal.

Delaying the need for chemotherapy would be a huge boost for cancer patients, as its toxic side effects can be highly destructive. Not only does it lead to hair loss, but it also causes nausea, extreme fatigue, and cripples the body’s immune system.