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Dignity Health: Diagnosing Stages of Breast Cancer with Expertise

Breast cancer staging defines the extent of cancer in the body. The stage at diagnosis determines your prognosis and guides treatment decisions. There are five stages for breast cancer: 0, I, II, III and IV. Higher staging numbers indicate more extensive disease. 

Lower stage breast cancers usually have better outcomes because they are more likely to respond to treatment. With cancer, there are no guarantees. Even the least invasive tumor has to be managed and monitored aggressively. However, catching breast cancer early can be key to successful treatment.

Experts at St. Joseph's Cancer Institute use blood tests, biopsy results, and imaging exams to stage breast cancer accurately. The results of tumor staging help your oncologist and care team create the most effective treatment strategy personalized to your needs. 

Stage 0

Stage 0 is noninvasive breast cancer, or ductal carcinoma in situ (DCIS). This is the earliest form of breast cancer. Cancer is growing in the milk ducts, but the cancer cells remain in place. Surgery and possibly hormone therapy or radiation are common treatments.


Stage I

Stage I is early invasive breast cancer. Cancer is growing into nearby breast tissues, but the tumor is still small. Surgery and radiation are usually the first treatments. Doctors typically recommend chemotherapy, hormone therapy, or targeted therapy afterward to remove any surviving cancer cells.


Stage II

Stage II also includes early forms of invasive breast cancer. The tumor is either larger than stage I or has spread to local lymph nodes. Treatment is similar to stage I. For large tumors, treatment before surgery, called neoadjuvant therapy, with chemotherapy, targeted therapies, or hormone therapy can help shrink the tumor. This can allow women to choose breast-conserving surgery instead of mastectomy.


Stage III

Stage III is locally advanced breast cancer. Cancer has spread to nearby lymph nodes and tissues, but has not spread to distant body sites. Treatment usually involves mastectomy and neoadjuvant therapy. Chemotherapy, radiation, hormone therapy, or immune-targeted therapy will come after surgery.


Stage IV

Stage IV is metastatic breast cancer. Cancer has spread beyond the breast and nearby lymph nodes to organs or other sites. Treatment aims to ease symptoms, shrink tumors, and lengthen life. Surgery is not useful in most cases.

While your cancer stage guides treatment decisions, your personal values are considered, too. Your doctor and nurse navigator will talk with you about the risks, benefits, and effects on your lifestyle for each treatment to find the right care. 

St. Joseph's Cancer Institute provides cancer services for the stages of breast cancer in the Stockton region.

Connect with a Breast Cancer Specialist 

Breast cancer affects women from all different walks of life. If you’re at risk, talk to your doctor about screening options. Don’t have a doctor? We can help. Use our Find a Doctor tool to locate a specialist near you.