In the early 1900's it was felt that the treatment of breast cancer required a radical and aggressive operation. However, as the decades have gone by and new research has been done, we have found that a big operation is not necessarily best in all situations. Initially, just removing the lump was the operation done for breast cancer. This was usually unsuccessful. The first successful operation performed for breast cancer was called a radical mastectomy. This was a very aggressive operation and removed both the breast and the underlying muscles and lymph glands. This operation it dramatically improved the cure rate of patients with breast cancer. Unfortunately, arm swelling was a common problem after this operation. 

In the mid 1900's studies were done that showed that a modified radical mastectomy has the same chance of curing breast cancer as does a radical mastectomy. This operation removes the breast and the lymph glands in the armpit, but it leaves the muscles beneath the breast in place. After the surgery the arm functions normally and has normal strength. It is unusual to develop arm swelling.

In the last 20 years, there has been extensive research to determine if it is always necessary to remove the entire. Researchers have found that in many cases it is possible to remove just the tumor along with a rim of normal tissue and obtain the same cure rate as with a modified radical mastectomy if the breast tissue that remains receives radiation treatments. It is also necessary to remove the lymph glands in the armpit to help us determine prognosis and further treatment recommendations. 

We call this combination of treatments partial mastectomy with axillary dissection and radiation. Other terms for "partial mastectomy" include lumpectomy, segmental mastectomy, quadrantectomy, wide excision, local excision, or limited excision.

Usually we remove all of the lymph glands in the armpit, but newer information suggests that in some situations only certain lymph glands called sentinel nodes need to be removed. 

There are several reasons why surgeons have changed their recommendations from mastectomy to partial mastectomy in some patients: 

• We are seeing smaller cancers than we did in the past because of greater patient awareness.
• Screening mammography is finding very early cancers.
• There is convincing data on patients followed for a long time showing good results of treatment with partial mastectomy. 
• Our theory of how breast cancer spreads has changed. In the past, it was believed that there was always an orderly progression of spread from the lump, to the lymph glands, to the bloodstream. Once in the bloodstream it could spread to distant organs. Because of this theory, past surgical treatment was aimed at aggressive local treatment, hoping to remove all fragments of the cancer before it had a chance to spread. We now know that although the above situation can occur, there are also situations where the cancer can enter the bloodstream and spread even before it has reached the lymph nodes. For this reason, we are now putting less importance on which particular operation is performed and more importance on systemic (total body) treatment given after the operation.