Breast Cancer

Breast cancer
Worldwide, breast cancer is the second most common type of cancer after lung cancer (10.4% of all cancer incidence, both sexes counted) 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).

A well-differentiated (low grade) tumor resembles normal tissue. Protein & gene expression status - Currently, all breast cancers should be tested for expression, or detectable effect, of the estrogen receptor (ER), progesterone receptor (PR) and HER2/neu proteins. Stage of a tumor - The currently accepted staging scheme for breast cancer is the TNM classification. Breast cancer is usually, but not always, primarily classified by its histological appearance. For example, inflammatory breast cancer (IBC), a form of ductal carcinoma or malignant cancer in the ducts, is distinguished from other carcinomas by the inflamed appearance of the affected breast. In the future, some pathologic classifications may be changed. The first symptom, or subjective sign, of breast cancer is typically a lump that feels different from the surrounding breast tissue. According to the The Merck Manual, more than 80% of breast cancer cases are discovered when the woman feels a lump.[According to the American Cancer Society, the first medical sign, or objective indication of breast cancer as detected by a physician, is discovered by mammogram. Lumps found in lymph nodes located in the armpits and/or collarbone can also indicate breast cancer.

Indications of breast cancer other than a lump may include changes in breast size or shape, skin dimpling, nipple inversion, or spontaneous single-nipple discharge. Pain is an unreliable tool in determining the presence or absence of breast cancer, but may be indicative of other breast health issues such as mastodynia.

When breast cancer cells invade the dermal lymphatics - small lymph vessels in the skin of the breast-its presentation can resemble skin inflammation and thus is known as inflammatory breast cancer (IBC). Symptoms of inflammatory breast cancer include pain, swelling, warmth and redness throughout the breast, as well as an orange-peel texture to the skin referred to as peau d'orange.

Another reported symptom complex of breast cancer is Paget's disease of the breast. Approximately half of women diagnosed with Paget's also have a lump in the breast.

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. 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. Most symptoms of breast disorder do not turn out to represent underlying breast cancer. Benign breast diseases such as mastitis and fibroadenoma of the breast are more common causes of breast disorder symptoms. There is no cure for breast cancer.

The first case-controlled study 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. 3. Abnormal growth factor signaling in the interaction between stromal cells and epithelial cells can facilitate malignant cell growth. For example, tumors can induce blood vessel growth (angiogenesis) by secreting various growth factors further facilitating cancer growth.

Experts believe that 95 percent of inherited breast cancer can be traced to one of two genes, which they call Breast Cancer 1 (BRCA1) and Breast Cancer 2 (BRCA2). Hereditary breast cancers can take the form of a site-specific hereditary breast cancer- cancers affecting the breast only- or breast- ovarian and other cancer syndromes. Breast cancer can be inherited both from female and male relatives.

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. Due to breast cancer is vary in different racial and ethnic group. 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.

Worldwide, breast cancer is by far the most common cancer amongst women, with an incidence rate more than twice that of colorectal cancer and cervical cancer and about three times that of lung cancer. However breast cancer mortality worldwide is just 25% greater than that of lung cancer in women. In 2004, breast cancer caused 519,000 deaths worldwide (7% of cancer deaths; almost 1% of all deaths). The incidence of breast cancer varies greatly around the world, being lower in less-developed countries and greatest in the more-developed countries. Women in the United States have the highest incidence rates of breast cancer in the world; 141 among white women and 122 among African American women.Among women in the US, breast cancer is the most common cancer and the second-most common cause of cancer death (after lung cancer). Women in the US have a 1 in 8 (12.5%) lifetime chance of developing invasive breast cancer and a 1 in 35 (3%) chance of breast cancer causing their death. In 2007, breast cancer was expected to cause 40,910 deaths in the US (7% of cancer deaths; almost 2% of all deaths).

Many doctors say that women exaggerate their risk of breast cancer.

Some studies suggest that the racial disparity in breast cancer outcomes may reflect cultural biases more than biological disease differences. Breast cancer screening is an attempt to find unsuspected cancers. The most common screening methods are self and clinical breast exams, x-ray mammography, and breast Magnetic Resonance Imaging (MRI). Breast self-examination involves examining one's own breasts using a specific palpation technique to detect any lumps in the breast tissue, which may be cancerous. A recent study involving 160,921 women recruited at age 39-41 showed that annual screening mammograms up to age 48 did decrease breast cancer mortality over an average of 10.7 years. According to these findings, about 2,500 women would need to be screened to prevent one breast cancer death during this time period.

The most recent technology for breast cancer screening is ultrasound computed tomography, which uses sound waves to create a three-dimensional image and detect breast cancer without the use of dangerous radiation used in x-ray mammography. Genetic testing for breast cancer typically involves testing for mutations in the BRCA genes. This is not generally a recommended technique except for those at elevated risk for breast cancer.

Diagnosis
Staging
Breast cancer is staged according to the TNM system, updated in the AJCC Staging Manual, now on its sixth edition. For a more detailed discussion on staging of breast cancer, see here.

Hormone receptors
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.

HER2
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. 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. 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. Radiation treatment is also used to help destroy cancer cells that may linger after surgery. Prognosis
The stage is raised by the invasiveness of disease to lymph nodes, chest wall, skin or beyond, and the aggressiveness of the cancer cells. The stage is lowered by the presence of cancer-free zones and close-to-normal cell behaviour (grading). Size is not a factor in staging unless the cancer invasive. Ductal Carcinoma in situ throughout the entire breast is stage zero.

The closer to normal cancer cells are, the slower their growth and the better the prognosis. The presence of estrogen and progesterone receptors in the cancer cell, while not prognostic, is important in guiding treatment. Elevated CA15-3, in conjunction with alkaline phosphatase, was shown to increase chances of early recurrence in breast cancer.

The emotional impact of cancer diagnosis, symptoms, treatment, and related issues can be severe. Most larger hospitals are associated with cancer support groups which provide a supportive environment to help patients cope and gain perspective from cancer survivors. 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. Premenopausal women with estrogen-receptor positive breast cancer must confront the issues of early menopause induced by many of the chemotherapy regimens used to treat their breast cancer, especially those that use hormones to counteract ovarian function.
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.

Metastasis
Most people understand breast cancer as something that happens in the breast. Breast cancer can also spread to other parts of the body via blood vessels or the lymphatic system. When breast cancer is found in bones, it has usually spread to more than one site. Like normal breast cells, these tumors in the bone often thrive on female hormones, especially estrogen. This important finding could potentially alter the way in which breast cancer is treated.

Breast cancer may be one of the oldest known forms of cancerous tumors in humans. In the month of October, breast cancer is recognized by survivors, family and friends of survivors and/or victims of the disease. The patron saint of breast cancer is Saint Agatha of Sicily.