Breast cancer occurs when abnormal cells grow out of control in the breast. Early-stage breast cancer means that the cancer cells haven't spread beyond the breast or the lymph nodes in the armpit.

The two different types of surgery used to treat early-stage breast cancer are:

• Breast-conserving surgery (lumpectomy), along with radiation therapy. During this type of surgery, the doctor cuts out the tumour and some of the breast tissue around it. Sometimes all of the cancer isn't removed during the first surgery. If this happens, you will need to have another surgery to remove more breast tissue. This is called re-excision. After surgery, you may or may not need chemotherapy.
• Mastectomy (removal of the breast). In most cases, you won't need radiation treatments after a mastectomy. And you may or may not need chemotherapy.
  • The removal of the entire breast is called a total or simple mastectomy. Some women choose to have both breasts removed. This is called a bilateral or double mastectomy.
  • The removal of the breast and the lymph nodes under the arm (axillary lymph nodes) is called a modified radical mastectomy.

With either breast-conserving surgery or mastectomy, you may need to have a few lymph nodes from under your arm sampled. This is called a sentinel node biopsy. Or you may need more lymph nodes removed. This is called an axillary lymph node dissection.

Your doctor will look at the type, size, and location of the tumour you have and the size of your breast to help learn which surgery may be right for you.

Your doctor may recommend that you have chemotherapy before surgery to shrink the tumour. This is called neoadjuvant therapy. It may make breast-conserving surgery an option, because less breast tissue has to be removed during surgery.

If you prefer breast-conserving surgery but are worried about radiation treatments, check with your doctor. Some women, such as those who are age 70 or older, may not need radiation.

Experts now know that there is no guarantee that breast cancer won't come back (recur) in the same breast after breast-conserving surgery or won't come back in the same area where your breast used to be after a mastectomy.

When comparing mastectomy versus breast-conserving surgery followed by radiation treatments, studies show:^{footnote 1}

• There's a very small difference in the chance of breast cancer coming back in the same breast or breast area. But breast-conserving surgery does have a slightly higher chance of cancer coming back in the same breast. That's because more breast tissue is left behind.
• There is no difference in survival.

Your surgeon may recommend a mastectomy if:

• You have two or more areas of breast cancer in the same breast that are too far apart to be removed with a single cut (incision).
• Your breast cancer is large or is large relative to the size of your breast, and removing it will require removing a lot of breast tissue. You may not be satisfied with the way your breast looks after surgery.
• You have had chemotherapy before surgery (called neoadjuvant therapy) to shrink the tumour, but it didn't reduce the size of the tumour enough to make breast-conserving surgery an option.
• You have a health reason that keeps you from being able to have radiation. Those reasons may include a serious lung disease, a connective tissue disease, or a problem that was already treated with radiation to the breast or chest.