NippleRibFatty tissueConnective tissueDuct openingTumorLobulesFigure 17.32Schematic illustrating the presence
of a cancer of the breast.SPECIFIC TYPES OF CANCERSCZhhVg6]bZY!BVjgZZc9Vlhdc!8]g^hHb^i]:YLddY *%&
around the nipple or a thickening behind the nipple, puckering or dimpling of
the skin of the breast or a swelling or lump in the armpit.
Mammography uses X-rays to locate the position of the potential tumor.
Mammography is also used to screen for cancer and, in the UK, this is
offered every three years to all women over the age of 50 years. The lump
may also be examined by ultrasound or by Color Doppler ultrasound,
which gives a picture of the blood supply to the lump. Microscopic
examination of cells from a fine needle aspirate of the lump may also be
helpful. Alternatively, the lump may be excised under a general anesthetic
for pathological examination.
The staging system for breast cancer describes two stages of noninvasive
and four stages of invasive breast cancer. Noninvasive stages include ductal
carcinoma in situ (DCIS) in which cancer cells are contained within the ducts.
If diagnosed at this stage, the disease is almost completely curable. Lobular
carcinoma in situ occurs when cancer cells are restricted to the lining of the
breast lobules. Stage 1 invasive cancer describes a tumor measuring less than
2 cm diameter, with no spread to the lymph nodes. In Stage 2 invasive cancer
the tumor measures between 2 and 5 cm and/or there are affected lymph
nodes. In Stage 3 invasive cancer the tumor is larger than 5 cm diameter and
may be attached to muscle or skin. The lymph nodes at this stage are usually
affected. Stage 4 invasive cancer describes a tumor of any size, the lymph
nodes are usually affected and the cancer has metastasized.
A microscopic examination of cancer cells allows their appearance to be graded.
Low grade or Grade 1 cancer cells have the appearance of differentiated normal
cells, whereas high grade (Grade 3) tumor cells have an abnormal appearance
and are characteristic of fast growing and aggressive cancers. The tumor cells
may also be examined immunohistochemically or by FISH (Section 17.6) to
detect expression of estrogen receptors or HER2 proteins on their surface.
Knowledge of the presence of either of these molecules allows the treatment
regimen to be determined more appropriately. Cells with estrogen receptors
may be stimulated to divide by naturally occurring estrogen, and hormone
therapy is indicated. The HER2 protein is a receptor for the human epidermal