Not until the very end of the 19th century did physicians or patients think that breast cancer was curable. Women only presented when the tumors were large and had spread to the axilla and beyond. Attempts to remove these lesions failed and resected cancers recurred so fast it seemed that the surgery fueled their growth. Halstead, operating just before the turn of the 20th century (at Johns Hopkins Hospital) believed that cancer cells were like seeds and that they migrated from the original tumor through the lymphatic system to the axilla. He believed that cutting through any tissue in the lymphatic system risked contaminating the operative field with cancer cells, any one of which could develop into a new tumor. If true, the best way to control these cancers was to remove the breast in 1 large block of tissue along with everything around it, all the way down to the bone of the chest wall.
Livingston EH, Li HC. Breast Cancer SurgeryLess Is More. JAMA. 2017;318(10):909–911. doi:10.1001/jama.2017.12890