A woman's breast is made up of glands that make breast milk, ducts that carry milk to the nipple, fatty and connective tissue, blood vessels, and lymph (pronounced “limf”) vessels. Most breast cancers begin in the cells that line the ducts, some begin in the glands, and a small number start in other tissues.
The lymph system is one of the main ways in which breast cancers can spread. Lymphatic vessels are like small veins, except that they carry a clear fluid called lymph (instead of blood) away from the breast. Breast cancer cells can enter lymphatic vessels and begin to grow in lymph nodes under the arm. The doctor needs to know whether cancer cells have spread to lymph nodes because if they have, there is a higher chance that the cells have also gotten into the bloodstream and spread to other places in the body. The more lymph nodes that have cancer in them, the more likely it is that cancer will be found in other organs, too. This could affect the treatment plan.
Types of treatments can be put into broad groups based on how they work and when they are used.
Local treatment is used to treat a tumor without affecting the rest of the body. Surgery and radiation are examples of local treatment.
Systemic treatment is given into the bloodstream or by mouth and goes throughout the body to reach cancer cells that may have spread beyond the breast. Chemotherapy (chemo), hormone therapy and targeted therapy are systemic treatments.
People who seem to have no cancer left after surgery may be given more treatment. This is called adjuvant therapy. Doctors know that cancer cells can break away from the main tumor and begin to spread through the bloodstream in the early stages of the disease. It's very hard to tell if this has happened. But if it has, the cancer cells can start new tumors in other organs or in the bones. The goal of adjuvant therapy is to kill these hidden cells. Both systemic therapy (like chemo, hormone treatment, and targeted therapy) and radiation can be used as adjuvant therapy. But not every patient needs adjuvant therapy.
Some people are given treatment before surgery to shrink a tumor. This is called neoadjuvant therapy.
Treatment by Stages
These cancers are still small and either have not spread to the lymph nodes or there is only a tiny area of cancer spread. Stage I cancers can be treated with either breast-conserving surgery (lumpectomy, partial mastectomy) or mastectomy. The lymph nodes will also need to be evaluated. Breast reconstruction can be done either at the same time as surgery or later. Radiation therapy is usually given after breast-conserving surgery. Women may consider breast-conserving surgery without radiation therapy in some cases.
These cancers are larger and/or have spread to a few nearby lymph nodes. Surgery and radiation therapy options for stage II tumors are similar to those for stage I tumors, except that in stage II, radiation therapy to the chest wall may be considered even after mastectomy if the tumor is or cancer cells are found in several lymph nodes. Adjuvant therapy is recommended for women with stage II breast cancer.
For some women who would like to have breast-conserving therapy but the tumor is too large, doctors may recommend treatment before surgery to shrink the tumor. If the treatment shrinks the tumor enough, women may then be able to have breast-conserving surgery (such as lumpectomy) followed by radiation therapy. If the tumor does not shrink enough for breast-conserving surgery, then mastectomy may be required. More therapy after surgery may also be given.
Stage III tumors must be large (greater than about two inches across) or growing into nearby tissues (the skin over the breast or the muscle underneath), or the cancer has spread to many nearby lymph nodes. Local treatment for some stage III breast cancers is basically the same as for stage II breast cancers. Tumors that are small enough (and have not grown into nearby tissues) may be removed by breast-conserving surgery (such as lumpectomy) which is followed by radiation therapy. Otherwise, the breast is treated with mastectomy (with or without breast reconstruction). Surgery is usually followed by chemotherapy, and/or hormone therapy. Radiation after mastectomy is often recommended.
Stage IV cancers have spread beyond the breast and lymph nodes to other parts of the body. Breast cancer most commonly spreads to the bones, liver, and lung. As the cancer progresses, it may spread to the brain, but it can affect any organ, even the eye.
Although surgery and/or radiation may be used in some situations, treatment usually includes systemic therapy such as hormone therapy, chemotherapy, targeted therapies or some combination of these. Treatment can help shrink tumors, improve symptoms, and help patients live longer, but it isn’t able to make the cancer go away and stay away.
All of the systemic therapies given for breast cancer — hormone therapy, chemotherapy, and targeted therapies — have potential side effects. Your doctor will explain the benefits and risks of these treatments before prescribing them.
View the AnMed Health Cancer Care 2018 Major Site Report for Breast Cancer (PDF).