Why hasn early detection decreased the number of breast cancer deaths?
Breast cancer is a disease of the body, not just of the breast. As medical researchers in the 1970s and 1980s discovered a great deal more about how breast cancer develops and progresses, their perceptions of the disease changed. The older understanding of the disease was that a tiny tumor became medium-sized, then large, then spread to the lymph nodes in the armpits, and finally entered the bloodstream to spread (metastasize) to other parts of the body where it became a life-threatening illness. This conception explains why the earlier recommended treatment for breast cancer was a total or radical mastectomy, the removal of the breast and lymph nodes and possibly the surrounding muscles. This treatment was believed to interfere with the final stage of breast cancer the spreading of cancerous cells from the lymph nodes into the bloodstream. The new understanding of breast cancer is that it is a systemic disease: any cancer large enough to feel is one that may have spread into the blood
