To test Conchita for cancer, her doctor used a thin needle to take a tissue sample from the lump. It contained cancer cells. So she had surgery to remove the tumor and the surrounding breast tissue and to determine the tumor’s stage (size, type, and spread) and grade (speed of growth).

After surgery, many patients have additional treatments aimed at preventing the recurrence or spread of the cancer. Cancer cells can break away from a tumor, travel through the bloodstream or the lymphatic system, and start growing again. The spread, or metastasis, of cancer to vital organs and tissues​—the brain, the liver, the bone marrow, or the lungs—​is what turns the disease deadly.

Conchita underwent both radiation and chemotherapy to destroy stray cancer cells around the original site and throughout her body. Since her form of cancer fed on estrogen, she also underwent antihormonal therapy to hinder the growth of new cancers.

Advances in breast cancer treatment offer other options to patients according to their age, health, cancer history, and the individual cancer. For instance, in the case of a woman named Arlette, tests revealed her cancer before it spread beyond the milk duct. So she had a lumpectomy, which saved her breast. Alice had chemotherapy before surgery to shrink her tumor. Janice’s surgeon removed the tumor and only the sentinel lymph node, the first node into which the fluid from the tumor drains. Since it held no cancer cells, additional nodes were left intact. This reduced Janice’s risk of lymphedema, an uncomfortable swelling of the arm that can occur when many lymph nodes are removed.

Are more-effective, less-traumatic treatments for breast cancer on the horizon? Researchers are developing therapies that involve using the body’s own immune system and drugs that target the molecular pathways that support cancer growth. Meanwhile, improved imaging technologies should help clinicians deliver radiation more precisely and effectively.

Scientists are also fighting on other fronts, including unlocking the mystery of metastasis, outwitting chemoresistant cancer cells, disrupting cellular-growth signals, and tailoring treatment to individual tumors.