It generally starts inside the milk ducts of the breast, then invades through the wall of the breast. I When the tumor is 1 inch across, there is a 30% chance that it has spread to the axillary lymph glands; when it is 2 inches across, the chance of the axilla being involved, or” positive” is about 60%. that is likely to have spread to other areas of the body through the bloodstream. The most common places for it to spread, in order, are the bones, liver, lung, skin and brain.