A common breast cancer treatment may soon become even more effective thanks to megestrol acetate, a synthetic hormone that mimics progesterone. New research from the University of Cambridge suggests that adding this drug to standard anti-oestrogen therapy not only eases troublesome side effects like hot flushes but may also slow tumour growth. The findings could mark a significant step forward for women with oestrogen receptor (ER)-positive breast cancer, offering a treatment that is both gentler on the body and more powerful against the disease. Targeting ER- positive breast cancer Around 75% of breast cancers are classified as ER-positive. In these cancers, tumour cells rely on oestrogen to grow and divide. Standard treatment often involves anti-oestrogen medications, such as letrozole, which block the hormone’s effects and inhibit cancer progression. However, these therapies can trigger menopause-like symptoms, including hot flushes, joint pain, and potential bone loss, which may prompt some patients to discontinue treatment. Megestrol acetate: A dual benefit Megestrol acetate has long been used to help women manage hot flushes caused by anti-oestrogen therapy. The PIONEER …