Only the cancer is removed but in order to prevent cancer from coming back breast conservation has to has be to combined with radiation.
Lumpectomy and partial mastectomy are different terms for the same operation: The healthy breast tissue remains in place and only the cancer is removed. Two major studies published in the 1980s showed that lumpectomy/partial mastectomy + radiation is just as good as removing the whole breast (total mastectomy).
Cancer patients with large or droopy breasts (ptosis) can have a lumpectomy/partial mastectomy and a breast reduction or a breast lift. The noncancer side can also be reduced or lifted so the breasts match (symmetry).
With a mastectomy the entire breast is moved. The different types of mastectomy are based on whether, in addition to the whole breast, the lymph nodes in the underarm, the skin and/or the nipple-areolar complexare removed as well.
Removal of the whole breast, the muscle, all of the skin and the lymph nodes
The same as a radical mastectomy except the muscle is not removed
Removal of the entire breast and most of the skin but not the lymph nodes
Removal of the whole breast and the nipple-areolar complex but all of the skin remains
Removal of the whole breast but all of the skin and the nipple-areolar complex are spared