LETS 2.5 mg LETS 2.5 mg contains Letrozole 2.5 mg, a hormonal anti-cancer medicine used to treat hormone receptor-positive breast cancer in postmenopausal women. It lowers the body's estrogen levels, reducing the hormone that can stimulate the growth of certain breast cancer cells. LETS 2.5 mg is commonly used after surgery, as initial treatment, or for advanced breast cancer to help control the disease and reduce the risk of recurrence. It should be taken exactly as prescribed by a healthcare professional.