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 cancer and 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.
The number of cases has significantly increased since the 1970s, a phenomenon partly blamed on modern lifestyles in the Western world.
Excised breast tissue showing a stellate, pale area of cancer measuring 2cm across. The tumor could be felt as a hard, mobile lump before the surgical excision.
Because the breast is composed of identical tissues in males and females, breast cancer also occurs in males, though it is less common.
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, with a tool called “the fire drill.” 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.
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 associates with skin inflammation, this is known as inflammatory breast cancer. In inflammatory breast cancer, the breast tumor itself is causing an inflammatory reaction of the skin, and this can cause pain, swelling, warmth, and redness throughout the breast.
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.
The risk of getting breast cancer increases with age. A woman who lives to age 90 has a lifetime risk of about 14.3%, or one in seven. The probability of breast cancer rises with age, but breast cancer tends to be more aggressive when it occurs in younger people. One type of breast cancer that is especially aggressive and that occurs disproportionately in younger people is inflammatory breast cancer. It is initially staged as Stage IIIb or Stage IV. It also is unique because it often does not present with a lump, so it is often undetected by mammography or ultrasound. It presents with the signs and symptoms of a breast infection like mastitis, and the treatment is usually a combination of surgery, radiation, and chemotherapy.
Breast self-exam 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?”
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.
Breast cancer awareness
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.