Breast Cancer Treatment Options

Breast cancer treatment depends on more than stage alone. It depends on the tumor's molecular subtype. Some tumors use estrogen or progesterone as fuel. Some make too much of a protein called HER2. Some have none of these features — doctors call that triple-negative. Two people can have the same size tumor and still get very different treatment plans. Their tumors run on different biology.

Most people with early-stage breast cancer have surgery to remove the tumor. There are two main paths. A lumpectomy, also called breast-conserving surgery, removes the tumor and a margin of normal tissue. It keeps the rest of the breast. A mastectomy removes the entire breast. Both are often followed by checking nearby lymph nodes. That tells your team whether the cancer has started to spread.

Which option is right depends on tumor size, location, and your own preference. For many early cancers, a lumpectomy plus radiation works about as well as a mastectomy. Both are effective at preventing the cancer from coming back in that breast.

Radiation therapy often follows a lumpectomy. It aims to destroy any cancer cells left behind in the breast tissue. It lowers the chance the cancer returns in that same spot. Radiation is used less often after a full mastectomy. It is still added when the tumor was large, or when lymph nodes were involved.

Many breast cancers have receptors for estrogen, progesterone, or both. That means the cancer's growth is fueled by these hormones. Hormone therapy blocks that fuel supply. Drugs like tamoxifen or aromatase inhibitors are taken for years. Often that means five to ten years, after other treatment ends. This only works for hormone-receptor-positive cancers. That is why every breast tumor is tested for these receptors before treatment planning begins.

About 1 in 5 breast cancers make too much of a protein called HER2. This protein drives faster growth. Drugs like trastuzumab target this protein directly. They block its growth signal. Combined with chemotherapy, HER2-targeted therapy has dramatically improved outcomes for this subtype. It used to carry a worse outlook before these drugs existed.

Chemotherapy is used when cancer has a higher risk of returning, or when it has already spread. It can be given before surgery, to shrink a tumor first. Doctors call this neoadjuvant treatment. It can also be given after surgery, to clean up cells too small to see. Triple-negative breast cancer lacks estrogen, progesterone, and HER2 receptors. For this type, immunotherapy is increasingly added alongside chemotherapy. It works by helping your immune system recognize and attack cancer cells. That is a different mechanism than chemotherapy's direct cell-killing action.

Your team weighs the tumor's stage, its subtype, and your own health and goals. Sometimes surgery comes first. Sometimes drug treatment comes first, to shrink the tumor, followed by surgery and then more drug treatment or radiation. This sequencing is not random. Shrinking a tumor before surgery can sometimes turn a mastectomy into a lumpectomy. Treating micro-spread early can lower the chance of recurrence years later.

• What is my tumor's subtype — hormone receptor status and HER2 status — and how does that shape my treatment?
• Would a lumpectomy or mastectomy be more appropriate for my situation?
• Will I have chemotherapy or other drug treatment before surgery, after it, or both?
• What side effects should I expect from each part of my plan?
• Is a clinical trial a reasonable option for me?

• American Cancer Society — Breast Cancer Treatment
• American Cancer Society — Stages of Breast Cancer