The first noticeable symptom is usually a lump or area of thickened breast tissue, though there are a number of perhaps lesser known signs which may occur.
Cancer Research suggests people be aware of a number of signs, which include the following:
A new lump or thickening in your breast or armpit
A change in size, shape or feel of your breast
Fluid leaking from the nipple in a person who isn’t pregnant or breastfeeding
Some people also experience skin changes, which “include puckering, dimpling, a rash, or redness of the skin of the breast. Others have a rash or redness of the nipple and the surrounding skin” and the skin might look like orange peel or the texture might feel different, it explains.