Breast neoplasms



Breast cancer is a cancer of the glandular breast tissue.

Worldwide, breast cancer is the fifth most common cause of cancer death (after lung cancer, stomach cancer, liver cancer, and colon cancer). In 2005, breast cancer caused 502,000 deaths (7% of cancer deaths; almost 1% of all deaths) worldwide. Among women worldwide, breast cancer is the most common cause of cancer death.

In the United States, breast cancer is the third most common cause of cancer death (after lung cancer and colon cancer). In 2007, breast cancer is expected to cause 40,910 deaths (7% of cancer deaths; almost 2% of all deaths) in the U.S. Among women in the U.S., breast cancer is the most common cancer and the second-most common cause of cancer death (after lung cancer). Women in the U.S. have a 1 in 8 lifetime chance of developing invasive breast cancer and a 1 in 33 chance of breast cancer causing their death. In the U.S., both incidence and death rates for breast cancer have been declining in the last few years. Nevertheless, a U.S. study conducted in 2005 by the Society for Women's Health Research indicated that breast cancer remains the most feared disease, even though heart disease is a much more common cause of death among women.

The number of cases worldwide has significantly increased since the 1970s, a phenomenon partly blamed on modern lifestyles in the Western world. Because the breast is composed of identical tissues in males and females, breast cancer also occurs in males, though it is less common.

Classification
Breast cancers are described along four different classification schemes, each based on different criteria and serving a different purpose :
 * Pathology - the pathologist will categorize each tumor based on its histological appearance and other criteria. The most common pathologic types of breast cancer are invasive ductal carcinoma and invasive lobular carcinoma. In the future, this pathologic classification may be changed. For example, a subset of ductal carcinomas may be re-named basal-like carcinoma (part of the "triple-negative" tumors). See Pathology classification section below.
 * Grade of tumor - the histological grade is determined by the pathologist under a microscope. A well-differentiated (low grade) tumor resembles normal tissue. A poorly differentiated (high grade) tumor is composed of disorganized cells and, therefore, does not look like normal tissue. Moderately differentiated (intermediate grade) tumors are somewhere in between.
 * Protein & gene expression status - currently, all breast cancers should be tested for expression of the estrogen receptor (ER), progesterone receptor (PR) and HER2/neu proteins. These tests are usually done by immunohistochemistry and reported in the pathologist's report. The profile of expression of a given tumor helps predict its prognosis and helps the oncologist chose the most appropriate treatment. More genes & proteins may be tested in the future.
 * Stage of the tumour. The currently accepted staging scheme for breast cancer is the TNM classification :
 * Tumor - five values (Tis, T1, T2, T3 or T4) depending on the presence or absence of invasive cancer, the dimensions of the invasive cancer and the presence or absence of invasion outside of the breast (e.g. to the skin of the breast, to the muscle or rib cage underneath).
 * Lymph Node - four values (N0, N1, N2 or N3) depending on the number, size and location of metastatic deposits in lymph nodes.
 * Metastases - two values (M0 or M1) depending on the presence or absence of metastases other than lymph nodes (so-called distant metastases, e.g. to bone, brain, lung).

Pathologic types
The latest (2003) WHO classification of tumors of the breast recommends the following histological types.

Invasive breast carcinomas
 * Invasive ductal carcinoma
 * Most are "not otherwise specified"
 * The remainder are given subtypes:
 * Mixed type carcinoma
 * Pleomorphic carcinoma
 * Carcinoma with osteoclastic giant cells
 * Carcinoma with choriocarcinomatous features
 * Carcinoma with melanotic features
 * Invasive lobular carcinoma
 * Tubular carcinoma
 * Invasive cribriform carcinoma
 * Medullary carcinoma
 * Mucinous carcinoma and other tumours with abundant mucin
 * Mucinous carcinoma
 * Cystadenocarcinoma and columnar cell mucinous carcinoma
 * Signet ring cell carcinoma
 * Neuroendocrine tumours
 * Solid neuroendocrine carcinoma (carcinoid of the breast)
 * Atypical carcinoid tumour
 * Small cell / oat cell carcinoma
 * Large cell neuroendocrine carcioma
 * Invasive papillary carcinoma
 * Invasive micropapillary carcinoma
 * Apocrine carcinoma
 * Metaplastic carcinomas
 * Pure epithelial metaplastic carciomas
 * Squamous cell carcinoma
 * Adenocarcinoma with spindle cell metaplasia
 * Adenosquamous carcinoma
 * Mucoepidermoid carcinoma
 * Mixed epithelial/mesenchymal metaplastic carcinomas
 * Lipid-rich carcinoma
 * Secretory carcinoma
 * Oncocytic carcinoma
 * Adenoid cystic carcinoma
 * Acinic cell carcinoma
 * Glycogen-rich clear cell carcinoma
 * Sebaceous carcinoma
 * Inflammatory carcinoma
 * Bilateral breast carcinoma

Precursor lesions
 * Lobular neoplasia
 * lobular carcinoma in situ
 * Intraductal proliferative lesions
 * Usual ductal hyperplasia
 * Flat epithelial hyperplasia
 * Atypical ductal hyperplasia
 * Ductal carcinoma in situ
 * Microinvasive carcinoma
 * Intraductal papillary neoplasms
 * Central papilloma
 * Peripheral papilloma
 * Atypical papilloma
 * Intraductal papillary carcinoma
 * Intracystic papillary carcinoma

Benign epithelial lesions Myoepithelial lesions
 * Adenosis, includin variants
 * Sclerosing adenosis
 * Apocrine adenosis
 * Blunt duct adenosis
 * Microglandular adenosis
 * Adenomyoepithelial adenosis
 * Radial scar / complex sclerosing lesion
 * Adenomas
 * Tubular adenoma
 * Lactating adenoma
 * Apocrine adenoma
 * Pleomorphic adenoma
 * Ductal adenoma
 * Myoepitheliosis
 * Adenomyoepithelial adenosis
 * Adenomyoepithelioma
 * Malignant myoepithelioma

Mesenchymal tumors (including sarcoma)
 * Haemangioma
 * Angiomatosis
 * Haemangiopericytoma
 * Pseudoangiomatous stromal hyperplasia
 * Myofibroblastoma
 * Fibromatosis (agressive)
 * Inflammatory myofibroblastic tumour
 * Lipoma
 * Angiolipoma
 * Granular cell tumour
 * Neurofibroma
 * Schwannoma
 * Angiosarcoma
 * Liposarcoma
 * Rhabdomyosarcoma
 * Osteosarcoma
 * Leiomyoma
 * Leiomysarcoma

Fibroepithelial tumours
 * Fibroadenoma
 * Phyllodes tumour
 * Benign
 * Borderline
 * Malignant
 * Periductal stromal sarcoma, low grade
 * Mammary hamartoma

Tumours of the nipple
 * Nipple adenoma
 * Syringomatous adenoma
 * Paget's disease of the nipple

Malignant lymphoma

metastatic tumours

Tumours of the male breast
 * Gynecomastia
 * Carcinoma
 * In situ
 * Invasive

The classification above shows that breast cancer is usually, but not always, classified by its histological appearance. Rare variants are defined on the basis of physical exam findings. For example, Inflammatory breast cancer (IBC), a form of ductal carcinoma, is distinguished from other carcinomas by the inflamed appearance of the affected breast.

Signs and symptoms
Early breast cancer can in some cases present as breast pain (mastodynia) or a painful lump. Since the advent of breast mammography, breast cancer is most frequently discovered as an asymptomatic nodule on a mammogram, before any symptoms are present. A lump under the arm or above the collarbone that does not go away may be present.

When breast cancer has invaded the dermal lymphatics - small lymph vessels of the skin, its presentation can resemble skin inflammation and thus is known as inflammatory breast cancer. In inflammatory breast cancer, the breast cancer is blocking lymphatic vessels and this can cause pain, swelling, warmth, and redness throughout the breast, as well as an orange peel texture to the skin referred to as peau d'orange. Although there may have been no previous signs of breast cancer and the cancer might be missed in screening mamograms, Inflammatory Breast Cancer is at least locally advanced at presentation (LABC) and Stage IIIB. Immediate staging tests are required to rule out distant metastes which might already be present making it Stage IV.

Changes in the appearance or shape of the breast can raise suspicions of breast cancer.

Another reported symptom complex of breast cancer is Paget's disease of the breast. This syndrome presents as eczematoid skin changes at the nipple, and is a late manifestation of an underlying breast cancer.

Most breast symptoms do not turn out to represent underlying breast cancer. Benign breast diseases such as fibrocystic mastopathy, mastitis, functional mastodynia, and fibroadenoma of the breast are more common causes of breast symptoms. The appearance of a new breast symptom should be taken seriously by both patients and their doctors, because of the possibility of an underlying breast cancer at almost any age.

Occasionally, breast cancer presents as metastatic disease, that is, cancer that has spread beyond the original organ. Metastatic breast cancer will cause symptoms that depend on the location of metastasis. More common sites of metastasis include bone, liver, lung, and brain. Unexplained weight loss can occasionally herald an occult breast cancer, as can symptoms of fevers or chills. Bone or joint pains can sometimes be manifestations of metastatic breast cancer, as can jaundice or neurological symptoms. Pleural effusions are not uncommon with metastatic breast cancer. Obviously, these symptoms are "non-specific," meaning they can also be manifestations of many other illnesses.

Epidemiology and etiology
Epidemiological risk factors for a disease can provide important clues as to the etiology of a disease. The first work on breast cancer epidemiology was done by Janet Lane-Claypon, who published a comparative study in 1926 of 500 breast cancer cases and 500 control patients of the same background and lifestyle for the British Ministry of Health.

Today, breast cancer, like other forms of cancer, is considered to be the final outcome of multiple environmental and hereditary factors.
 * 1) Lesions to DNA such as genetic mutations.  Exposure to estrogen has been experimentally linked to the mutations that cause breast cancer.  Beyond the contribution of estrogen, research has implicated viral oncogenesis and the contribution of ionizing radiation.
 * 2) Failure of immune surveillance, which usually removes malignancies at early phases of their natural history.
 * 3) Abnormal growth factor signaling in the interaction between stromal cells and epithelial cells, for example in the angiogenesis necessary to promote new blood vessel growth near new cancers.
 * 4) Inherited defects in DNA repair genes, such as BRCA1, BRCA2 and p53.

Although many epidemiological risk factors have been identified, the cause of any individual breast cancer is often unknowable. In other words, epidemiological research informs the patterns of breast cancer incidence across certain populations, but not in a given individual. The primary risk factors that have been identified are sex, age, childbearing, hormones, a high-fat diet, alcohol intake, obesity, and environmental factors such as tobacco use and radiation.

No etiology is known for 95% of breast cancer cases, while approximately 5% of new breast cancers are attributable to hereditary syndromes. In particular, carriers of the breast cancer susceptibility genes, BRCA1 and BRCA2, are at a 30-40% increased risk for breast and ovarian cancer, depending on in which portion of the protein the mutation occurs.

Phytoestrogens and soy
Phytoestrogens such as found in soybeans have been extensively studied in animal and human in-vitro and epidemiological studies. The literature support the following conclusions:
 * 1) Plant estrogen intake, such as from soy products, in early adolescence may protect against breast cancer later in life.
 * 2) Plant estrogen intake later in life is not likely to influence breast cancer incidence either positively or negatively.

Folic acid (folate)
Studies have found that "folate intake counteracts breast cancer risk associated with alcohol consumption" and "women who drink alcohol and have a high folate intake are not at increased risk of cancer." A prospective study of over 17,000 women found that  those who consume 40 grams of alcohol (about 3-4 drinks) per day have a higher risk of breast cancer. However, in women who take 200 micrograms of folate (folic acid or Vitamin B9) every day, the risk of breast cancer drops below that of alcohol abstainers.

Folate is involved in the synthesis, repair, and functioning of DNA, the body’s genetic map, and a deficiency of folate may result in damage to DNA that may lead to cancer. In addition to breast cancer, studies have also associated diets low in folate with increased risk of pancreatic, and colon cancer.

Foods rich in folate include citrus fruits, citrus juices, dark green leafy vegetables (such as spinach), dried beans, and peas. Vitamin B9 can also be taken in a multivitamin pill.

Avoiding exposure to secondhand tobacco smoke
Breathing secondhand smoke increases breast cancer risk by 70% in younger, primarily premenopausal women. The California Environmental Protection Agency has concluded that passive smoking causes breast cancer and the US Surgeon General has concluded that the evidence is "suggestive," one step below causal. There is some evidence that exposure to tobacco smoke is most problemmatic between puberty and first childbirth. The reason that breast tissue appears most sensitive to chemical carcinogens in this phase is that breast cells are not fully differentiated until lactation.

Oophorectomy and mastectomy
Prophylactic oophorectomy (removal of ovaries), in high-risk individuals, when child-bearing is complete, reduces the risk of developing breast cancer by 60%, as well as reducing the risk of developing ovarian cancer by 96%.

Bilateral prophylactic mastectomies have been shown to prevent breast cancer in high-risk individuals, such as patients with BRCA1 or BRCA2 gene mutations.

Medications
Hormonal therapy has been used for chemoprevention in individuals at high risk for breast cancer. In 2002, a clinical practice guideline by the US Preventive Services Task Force (USPSTF) recommended that "clinicians discuss chemoprevention with women at high risk for breast cancer and at low risk for adverse effects of chemoprevention" with a grade B recommendation.

Selective estrogen receptor modulators (SERMs)
The guidelines were based on studies of SERMs from the MORE, BCPT P-1, and Italian trials. In the MORE trial, the relative risk reduction for raloxifene was 76%. The P-1 preventative study demonstrated that tamoxifen can prevent breast cancer in high-risk individuals. The relative risk reduction was up to 50% of new breast cancers, though the cancers prevented were more likely estrogen-receptor positive (this is analogous to the effect of finasteride on the prevention of prostate cancer, in which only low-grade prostate cancers were prevented). The Italian trial showed benefit from tamoxifen.

Additional randomized controlled trials have been published since the guidelines. The IBIS trial found benefit from tamoxifen. In 2006, the NSABP STAR trial demonstrated that raloxifene had equal efficacy in preventing breast cancer compared with tamoxifen, but that there were fewer side effects with raloxifene. The RUTH Trial concluded that "benefits of raloxifene in reducing the risks of invasive breast cancer and vertebral fracture should be weighed against the increased risks of venous thromboembolism and fatal stroke". On September 14, 2007, the US Food and Drug Administration approved raloxifene (Evista) to prevent invasive breast cancer in postmenopausal women.

Screening
Breast cancer screening is an attempt to find unsuspected cancers. The most common screening methods are self and clinical breast exams, x-ray mammography, Breast Magnetic resonance imaging (MRI), ultrasound, Miraluma and genetic testing.

Breast self-exam
Breast self-examination was widely discussed in the 1990s as a useful modality for detecting breast cancer at an earlier stage of presentation. A large clinical trial in China reduced enthusiasm for breast self-exam. In the trial, reported in the Journal of the National Cancer Institute first in 1997 and updated in 2002, 132,979 female Chinese factory workers were taught by nurses at their factories to perform monthly breast self-exam, while 133,085 other workers were not taught self-exam. The women taught self-exam tended to detect more breast nodules, but their breast cancer mortality rate was no different from that of women in the control group. In other words, women taught breast self-exam were mostly likely to detect benign breast disease, but were just as likely to die of breast cancer. An editorial in the Journal of the National Cancer Institute reported in 2002, "Routinely Teaching Breast Self-Examination is Dead. What Does This Mean?"

Genetic testing
A clinical practice guideline by the US Preventive Services Task Force :
 * "recommends against routine referral for genetic counseling or routine breast cancer susceptibility gene (BRCA) testing for women whose family history is not associated with an increased risk for deleterious mutations in breast cancer susceptibility gene 1 (BRCA1) or breast cancer susceptibility gene 2 (BRCA2)" The Task Force gave a grade D recommendation.
 * "recommends that women whose family history is associated with an increased risk for deleterious mutations in BRCA1 or BRCA2 genes be referred for genetic counseling and evaluation for BRCA testing." The Task Force gave a grade B recommendation.

The Task Force noted that about 2% of women have family histories that indicate increased risk as defined by:
 * For non–Ashkenazi Jewish women, any of the following:
 * "2 first-degree relatives with breast cancer, 1 of whom received the diagnosis at age 50 years or younger"
 * "3 or more first- or second-degree relatives with breast cancer regardless of age at diagnosis"
 * "both breast and ovarian cancer among first- and second- degree relatives"
 * "a first-degree relative with bilateral breast cancer"
 * "a combination of 2 or more first- or second-degree relatives with ovarian cancer regardless of age at diagnosis"
 * "a first- or second-degree relative with both breast and ovarian cancer at any age"
 * "a history of breast cancer in a male relative."
 * "For women of Ashkenazi Jewish heritage, an increased-risk family history includes any first-degree relative (or 2 second-degree relatives on the same side of the family) with breast or ovarian cancer."

Diagnosis
Breast cancer is diagnosed by the examination of surgically removed breast tissue. A number of procedures can obtain tissue or cells prior to definitive treatment for histological or cytological examination. Such procedures include fine-needle aspiration, nipple aspirates, ductal lavage, core needle biopsy, and local surgical excision. These diagnostic steps, when coupled with radiographic imaging, are usually accurate in diagnosing a breast lesion as cancer. Occasionally, pre-surgical procedures such as fine needle aspirate may not yield enough tissue to make a diagnosis, or may miss the cancer entirely. Imaging tests are sometimes used to detect metastasis and include chest X-ray, bone scan, Cat scan, MRI, and PET scanning. While imaging studies are useful in determining the presence of metastatic disease, they are not in and of themselves diagnostic of cancer. Only microscopic evaluation of a biopsy specimen can yield a cancer diagnosis. Ca 15.3 (carbohydrate antigen 15.3, epithelial mucin) is a tumor marker determined in blood which can be used to follow disease activity over time after definitive treatment. Blood tumor marker testing is not routinely performed for the screening of breast cancer, and has poor performance characteristics for this purpose.

Staging
Breast cancer is staged according to the TNM system, updated in the AJCC Staging Manual, now on its sixth edition. Prognosis is closely linked to results of staging, and staging is also used to allocate patients to treatments both in clinical trials and clinical practice. The information for staging is as follows:

TX: Primary tumor cannot be assessed. T0: No evidence of tumor. Tis: Carcinoma in situ, no invasion T1: Tumor is 3 cm or less T2: Tumor is more than 2 cm but not more than 5 cm T3: Tumor is more than 5 cm  T4: Tumor of any size growing into the chest wall or skin, or inflammatory breast cancer

NX: Nearby lymph nodes cannot be assessed N0: Cancer has not spread to regional lymph nodes. N1: Cancer has spread to 1 to 3 axillary or one internal mammary lymph node N2: Cancer has spread to 4 to 9 axillary lymph nodes or multiple internal mammary lymph nodes N3: One of the following applies:

Cancer has spread to 10 or more axillary lymph nodes, or Cancer has spread to the lymph nodes under the clavicle (collar bone), or Cancer has spread to the lymph nodes above the clavicle, or Cancer involves axillary lymph nodes and has enlarged the internal mammary lymph nodes, or Cancer involves 4 or more axillary lymph nodes, and tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy.

MX: Presence of distant spread (metastasis) cannot be assessed. M0: No distant spread. M1: Spread to distant organs, not including the supraclavicular lymph node, has occurred

Summary of stages:
 * Stage 0 - Carcinoma in situ
 * Stage I - Tumor (T) does not involve axillary lymph nodes (N).
 * Stage IIA – T 2-5 cm, N negative, or T <2 cm and N positive.
 * Stage IIB – T > 5 cm, N negative, or T 2-5 cm and N positive (< 4 axillary nodes).
 * Stage IIIA – T > 5 cm, N positive, or T 2-5 cm with 4 or more axillary nodes
 * Stage IIIB – T has penetrated chest wall or skin, and may have spread to < 10 axillary N
 * Stage IIIC – T has > 10 axillary N, 1 or more supraclavicular or infraclavicular N, or internal mammary N.
 * Stage IV – Distant metastasis (M)

Breast lesions are examined for certain markers, notably sex steroid hormone receptors. About two thirds of postmenopausal breast cancers are estrogen receptor positive (ER+) and  progesterone receptor positive (PR+). Receptor status modifies the treatment as, for instance, only ER-positive tumors, not ER-negative tumors, are sensitive to hormonal therapy.

The breast cancer is also usually tested for the presence of human epidermal growth factor receptor 2, a protein also known as HER2, neu or erbB2. HER2 is a cell-surface protein involved in cell development. In normal cells, HER2 controls aspects of cell growth and division. When activated in cancer cells, HER2 accelerates tumor formation. About 20-30% of breast cancers overexpress HER2. Those patients may be candidates for the drug trastuzumab, both in the postsurgical setting (so-called "adjuvant" therapy), and in the metastatic setting.

Treatment
The mainstay of breast cancer treatment is surgery when the tumor is localized, with possible adjuvant hormonal therapy (with tamoxifen or an aromatase inhibitor), chemotherapy, and/or radiotherapy. At present, the treatment recommendations after surgery (adjuvant therapy) follow a pattern. This pattern is subject to change, as every two years, a worldwide conference takes place in St. Gallen, Switzerland, to discuss the actual results of worldwide multi-center studies. Depending on clinical criteria (age, type of cancer, size, metastasis) patients are roughly divided to high risk and low risk cases, with each risk category following different rules for therapy. Treatment possibilities include radiation therapy, chemotherapy, hormone therapy, and immune therapy.

In planning treatment, doctors can also use PCR tests like Oncotype DX or microarray tests like MammaPrint that predict breast cancer recurrence risk based on gene expression. In February 2007, the MammaPrint test became the first breast cancer predictor to win formal approval from the Food and Drug Administration. This is a new gene test to help predict whether women with early-stage breast cancer will relapse in 5 or 10 years, this could help influence how aggressively the initial tumor is treated.

Prognosis
A prognosis is the medical team's "best guess" in how cancer will affect a patient. There are many prognostic factors associated with breast cancer: staging, tumour size and location, grade, whether disease is systemic (has metastasized, or traveled to other parts of the body), recurrence of the disease, and age of patient.

Stage is the most important, as it takes into consideration size, local involvement, lymph node status and whether metastatic disease is present. The higher the stage at diagnosis, the worse the prognosis. Larger tumours, invasiveness of disease to lymph nodes, chest wall, skin or beyond, and aggressiveness of the cancer cells raise the stage, while smaller tumours, cancer-free zones, and close to normal cell behaviour (grading) lower it.

Grading is based on how cultured biopsied cells behave. The closer to normal cancer cells are, the slower their growth and a better prognosis. If cells are not well differentiated, they appear immature, divide more rapidly, and tend to spread. Well differentiated is given a grade of 1, moderate is grade 2, while poor or undifferentiated is given a higher grade of 3 or 4 (depending upon the scale used).

Younger women tend to have a poorer prognosis than post-menopausal women due to several factors. Their breasts are active with their cycles, they may be nursing infants, and may be unaware of changes in their breasts. Therefore, younger women are usually at a more advanced stage when diagnosed.

The presence of estrogen and progesterone receptors in the cancer cell, while not prognostic, is important in guiding treatment. Those who do not test positive for these specific receptors will not respond to hormone therapy.

Likewise, HER2/neu status directs the course of treatment. Patients whose cancer cells are positive for HER2/neu have more aggressive disease and may be treated with trastuzumab, a monoclonal antibody that targets this protein.

Psychological aspects of diagnosis and treatment
The emotional impact of cancer diagnosis, symptoms, treatment, and related issues can be severe. Most larger hospitals are associated with cancer support groups which can help patients cope with the many issues that come up in a supportive environment with other people with experience with similar issues. Online cancer support groups are also very beneficial to cancer patients, especially in dealing with uncertainty and body-image problems inherent in cancer treatment.

Not all breast cancer patients experience their illness in the same manner. Factors such as age can have a significant impact on the way a patient copes with a breast cancer diagnosis. For example, a recent study conducted by researchers at the College of Public Health of the University of Georgia showed that older women may face a more difficult recovery from breast cancer than their younger counterparts. As the incidence of breast cancer in women over 50 rises and survival rates increase, breast cancer is increasingly becoming a geriatric issue that warrants both further research and the expansion of specialized cancer support services tailored for specific age groups.

Racial disparities in diagnosis and treatment
Several studies have found that black women in the U.S. are more likely to die from breast cancer even though white women are more likely to be diagnosed with the disease. Even after diagnosis, black women are less likely to get treatment compared to white women. Scholars have advanced several theories for the disparities, including inadequate access to screening, reduced availability of the most advanced surgical and medical techniques, or some biological characteristic of the disease in the African American population. Some studies suggest that the racial disparity in breast cancer outcomes may reflect cultural biases more than biological disease differences. Research is currently ongoing to define the contribution of both biological and cultural factors.

Metastasis
Most people understand breast cancer as something that happens in the breast. However it can metastasise (spread) via lymphatics to nearby lymph nodes, usually those under the arm. That is why surgery for breast cancer always involves some type of surgery for the glands under the arm &mdash; either axillary clearance, sampling, or sentinel node biopsy.

Breast cancer can also spread to other parts of the body via blood vessels or the lymphatic system. So it can spread to the lungs, pleura (the lining of the lungs), liver, brain, and most commonly to the bones. Seventy percent of the time that breast cancer spreads to other locations, it spreads to bone, especially the vertebrae and the long bones of the arms, legs, and ribs. Breast cancer cells "set up house" in the bones and form tumors. Usually when breast cancer spreads to bone, it eats away healthy bone, causing weak spots, where the bones can break easily. That is why breast cancer patients are often seen wearing braces or using a wheelchair, and why they complain about aching bones.

When breast cancer is found in bones, it has usually spread to more than one site. At this stage, it is treatable, often for many years, but it is not curable. Like normal breast cells, these tumors in the bone often thrive on female hormones, especially estrogen. Therefore, the doctor often treats the patient with medicines that lower estrogen levels.

History
Breast cancer may be one of the oldest known forms of cancer tumors in humans. The oldest description of cancer (although the term cancer was not used) was discovered in Egypt and dates back to approximately 1600 BC. The Edwin Smith Papyrus describes 8 cases of tumors or ulcers of the breast that were treated by cauterization.The writing says about the disease, "There is no treatment." For centuries, physicians described similar cases in their practises, with the same sad conclusion. It wasn't until doctors achieved greater understanding of the circulatory system in the 17th century that they could establish a link between breast cancer and the lymph nodes in the armpit. The French surgeon Jean Louis Petit (1674-1750) and later the Scottish surgeon Benjamin Bell (1749-1806) were the first to remove the lymph nodes, breast tissue, and underlying chest muscle. Their successful work was carried on by William Stewart Halsted who started performing mastectomies in 1882. He became known for his Halsted radical mastectomy, a surgical procedure that remained popular up to the 1970s.

Cultural references
In the month of October, breast cancer is recognized by survivors, family and friends of survivors and/or victims of the disease. A pink ribbon is worn to recognize the struggle that sufferers face when battling the cancer.

Pink for October is an initiative started by Matthew Oliphant, which asks that any sites willing to help make people aware of breast cancer, change their template or layout to include the color pink, so that when visitors view the site, they see that the majority of the site is pink. Then after reading a short amount of information about breast cancer, or being redirected to another site, they are aware of the disease itself.

The patron saint of breast cancer is Saint Agatha of Sicily.