Breast cancer

- Breast cancer is cancer originating from breast tissue.

- Worldwide, breast cancer comprises 10.4% of all cancer incidence among women, making it the most common type of non-skin
cancer in women and the fifth most common cause of cancer death. In 2004, breast cancer caused 519,000 deaths worldwide (7% of
cancer deaths; almost 1% of all deaths). Breast cancer is about 100 times more common in women than in men, although males tend
to have poorer outcomes due to delays in diagnosis.
- Current statistics indicate that over an entire lifetime, a woman’s risk of developing breast cancer is one in eight.When broken down
by age, the risk by thirty nine years of age is 1 in 210, and it increases to 1 in 26 by 59 years of age.Approximately 80% of breast
cancers are diagnosed in women older than 50 years of age.

Types of breast cancer

Ductal carcinoma in situ

- is characterized by the proliferation of malignant cells inside the milk ducts without invasion in the surrounding tissue.
Therefore, it is non invasive form of cancer. It is frequently manifested on a mammogram with the appearance of
calcifications, and it is considered breast cancer stage 0.

Infiltrating Ductal Carcinoma

- the most common histologic type of breast cancer, accounts for 80% of all cases. The tumors arise from the duct system and
invade the surrounding tissues. They often form a solid irregular mass in the breast.

Infiltrating Lobular Carcinoma

- accounts for 10% to 15% of the breat cancers. The tumor arise from the lobular epithelium and typically occur as an area of
ill-defined thickening in the breast. They are often multicentric and can be bilateral.

Medullary carcinoma
 - accounts for about 5% of breat cancers, and it tends to be diagnosed more often in women younger than 50 years of age.
The tumor grow in a capsule inside a duct. They can become large and may be mistaken for a fibroadenoma. The prognosis
is often favorable.

Mucinous Carcinoma

- accounts for about 3% of breast cancer and often presents in postmenopausal women 75 years of age and older. A mucin
producer, the tumor is also slow growing and thus the prognosis is more favorable than in many types.

Tubular Ductal Carcinoma

- accounts for about 2% of breast cancers. Because axillary metastases are uncommon with this histology, prognosis is usually
excellent.

Inflammatory Carcinoma

- is a rare (1% to 3%) and aggressive type of breast cancer that has a unique symptoms. The cancer is characterized by diffuse
edema and brawny erythema of the skin, often reffered to as peau d orange(resembling an orange peel). This is caused by
the malignant cells blocking the lymph channels in the skin. The disese can spread to other parts of the body rapidly.
Chemotherapy often plays an initial role in controlling disease progression, but radiation and surgery may also be useful.

Paget’s disease

- accounts for 1% of diagnosed cases of breast cancer. Symptoms typically include a scaly erythematous, pruritic lesion of the
nipple. Paget’s disease often represents ductal carcinoma in situ of the nipple but may have an invasive component. If no
lump can be felt in the breast tissue and the biopsy shows DCIS without invasion, the prognosis is very favorable.

Risk Factors

- there is no specific cause of breast cancer. A combination of genetic, hormonal, and possibly environmental factors may
increase the risk if its development. More than 80% of all cases of breast cancer are sporadic, meaning that patients have no
known family history of the disease. The remaining cases are either familial or genetically acquired.
Breast cancer stage grouping

Once the T, N, and M categories have been determined, this information is combined in a process called stage grouping. Cancers with similar
stages tend to have a similar outlook and thus are often treated in a similar way. Stage is expressed in Roman numerals from stage I (the least
advanced stage) to stage IV (the most advanced stage). Non-invasive cancer is listed as stage 0.

Stage 0: Tis, N0, M0:  This is  ductal carcinoma in situ (DCIS), the earliest form of breast cancer. In DCIS, cancer cells are still within a duct and
have not invaded deeper into the surrounding fatty breast tissue. Lobular carcinoma in situ (LCIS) is sometimes also classified as stage 0 breast
cancer, but most oncologists believe it is not a true breast cancer. In LCIS, abnormal cells grow within the lobules or milk-producing glands, but
they do not penetrate through the wall of these lobules. Paget disease of the nipple (without an underlying tumor mass) is also stage 0. In all
cases the cancer has not spread to lymph nodes or distant sites.

Stage IA: T1, N0, M0:  The tumor is 2 cm (about 3/4 of an inch) or less across and has not spread to lymph nodes or distant sites.

Stage IB: T0 or T1, N1mi, M0: The tumor is 2 cm or less across (or is not found) with micrometastases in 1 to 3 axillary lymph nodes (the cancer
in the lymph nodes is greater than 0.2mm across and/or more than 200 cells but is not larger than 2 mm). The cancer has not spread to distant
sites.

Stage IIA: T0 or T1, N1 (but not N1mi), M0 / T2, N0, M0: One of the following applies:

 The tumor is 2 cm or less across (or is not found) (T1 or T0) and has spread to 1 to 3 axillary lymph nodes, with the cancer in the lymph
nodes larger than 2 mm across (N1a).

 The tumor is 2 cm or less across (or is not found) (T1 or T0) and tiny amounts of cancer are found in internal mammary lymph nodes on
sentinel lymph node biopsy (N1b).

 The tumor is 2 cm or less across (or is not found) (T1 or T0) and has spread to 1 to 3 lymph nodes under the arm and to internal
mammary lymph nodes (found on sentinel lymph node biopsy) (N1c).

 The tumor is larger than 2 cm across and less than 5 cm (T2) but hasn't spread to the lymph nodes (N0).

The cancer hasn't spread to distant sites (M0).

Stage IIB: T2, N1, M0 / T3, N0, M0:  One of the following applies:
  The tumor is larger than 2 cm and less than 5 cm across. It has spread to 1 to 3 axillary lymph nodes and/or tiny amounts of cancer are
found in internal mammary lymph nodes on sentinel lymph node biopsy (T2, N1).

 The tumor is larger than 5 cm across but does not grow into the chest wall or skin and has not spread to lymph nodes (T3, N0).

The cancer hasn't spread to distant sites (M0).

Stage IIIA: T0 to T2, N2, M0 / T3, N1 or N2, M0: One of the following applies:

 The tumor is not more than 5 cm across (or cannot be found). It has spread to 4 to 9 axillary lymph nodes, or it has enlarged the internal
mammary lymph nodes (T0 to T2, N2).

 The tumor is larger than 5 cm across but does not grow into the chest wall or skin. It has spread to 1 to 9 axillary nodes, or to internal
mammary nodes (T3, N1 or N2).

The cancer hasn't spread to distant sites (M0).

Stage IIIB: T4, N0 to N2, M0: The tumor has grown into the chest wall or skin (T4), and one of the following applies:

 It has not spread to the lymph nodes (N0).

 It has spread to 1 to 3 axillary lymph nodes and/or tiny amounts of cancer are found in internal mammary lymph nodes on sentinel
lymph node biopsy (N1).

 It has spread to 4 to 9 axillary lymph nodes, or it has enlarged the internal mammary lymph nodes (N2).

The cancer hasn't spread to distant sites (M0).

Inflammatory breast cancer is classified as T4 and is stage IIIB unless it has spread to distant lymph nodes or organs, in which case it would be
stage IV.

Stage IIIC: any T, N3, M0: The tumor is any size (or can't be found), and one of the following applies:

 Cancer has spread to 10 or more axillary lymph nodes (N3).

  Cancer has spread to the lymph nodes under the clavicle (collar bone) (N3).

 Cancer has spread to the lymph nodes above the clavicle (N3).

 Cancer involves axillary lymph nodes and has enlarged the internal mammary lymph nodes (N3).

 Cancer has spread to 4 or more axillary lymph nodes, and tiny amounts of cancer are found in internal mammary lymph nodes on
sentinel lymph node biopsy (N3).

The cancer hasn't spread to distant sites (M0).

Stage IV: any T, any N, M1: The cancer can be any size (any T) and may or may not have spread to nearby lymph nodes (any N). It has spread to
distant organs or to lymph nodes far from the breast (M1). The most common sites of spread are the bone, liver, brain, or lung,

Breast cancer survival rates by stage

Stage 5-year Relative Survival Rate

0 100%

I 100%

II 86%

III 57%

IV 20%