XTANE 25MG TABLET belongs to the group of cancer-fighting medications known as antineoplastics. Exemestane is often used to treat breast cancers that depend on estrogen for growth and survival. It is used to treat breast cancer in women who are past menopause and who are no longer responding to the beneficial effects of tamoxifen, another antineoplastic medication. Exemestane may also be used to treat advanced breast cancer in post-menopausal women who have had the disease continue to grow, even after anti-estrogen treatment. Exemestane fights cancer by attaching to and inactivating an enzyme called aromatase. This prevents the aromatase enzyme from supplying the estrogen that allows certain types of breast cancers to grow and survive.