Breast cancer
A new lump in the breast is the most common symptom of breast cancer, though many people have no symptoms at diagnosis. Most breast lumps are not cancer, but painless, hard lumps with irregular edges raise suspicion. Other physical changes include skin thickening known as peau d'orange swelling or dimpling of the skin. Fluid coming from the nipple may appear red or clear, and a newly inverted nipple can signal trouble. Redness, dryness, or scaly patches on the skin sometimes indicate inflammatory breast cancer. Up to 5% of cases involve inflammatory breast cancer where cells block lymph vessels causing substantial swelling over three to six months. Paget's disease affects up to 3% of patients with eczema-like irritation on the nipple and areola. Advanced tumors metastasize to bones, liver, lungs, or brain causing bone pain, jaundice, shortness of breath, or seizures. Bone metastases weaken bones leading to fractures while liver spread causes abdominal pain and vomiting. Lung metastases bring chest pain and regular coughing. Brain metastases disrupt speech, vision, memory, and behavior.
Mammography uses low-dose X-ray imaging to press each breast between two plates for early detection. Radiologists report results on the six-point Breast Imaging-Reporting and Data System scale where higher numbers mean greater risk. Dense breast tissue appears opaque on mammograms obscuring tumors in extremely dense breasts. Mammography detects around 90% of tumors in fatty breasts but only 60% in extremely dense ones. Women with dense breasts may use ultrasound, magnetic resonance imaging, or tomosynthesis instead. Regular screening reduces breast cancer deaths by at least 20%. Most guidelines recommend annual mammograms for women aged 50 to 70. Screening also reduces mortality in women aged 40 to 49 though some guidelines differ. For high-risk women adding MRI screening increases chances of detecting dangerous tumors. Overall mammograms miss about one in eight cancers and cause false-positive results. False positives create extra anxiety and lead to unnecessary biopsies. Clinical breast exams remain common but their impact on survival is unknown. Regular self-examination does not reduce death rates from the disease.
A biopsy taken via core needle collects tissue from suspected tumors for confirmation. Around 10 to 20 percent of biopsies test positive for cancer while most masses are benign fibrocystic changes. Tumors arising from mammary ducts account for 85 percent of cases as ductal carcinomas. Lobular carcinomas make up 10 percent derived from mammary lobes. Rarer types include mucinous carcinoma at 2.5 percent and tubular carcinoma at 1.5 percent. Carcinoma in situ often appears precancerous with around a third developing invasive cancer within five years. Breast tumors receive grades based on three features scored on a three-point scale each. Combined scores of 3, 4, or 5 represent grade 1 slow-growing cancers. Scores of 6 or 7 indicate grade 2 while 8 or 9 signify grade 3 aggressive cancers. Immunohistochemistry tests determine estrogen receptor presence progesterone receptor status and HER2 protein levels. Hormone receptor-positive tumors comprise about 70 percent of patients. Triple-negative tumors lacking all three markers grow more quickly than other types. The TNM staging system assigns T scores by tumor size N scores by lymph node spread and M scores by metastasis evidence. Stage groups range from I best prognosis to IV worst prognosis regardless of other characteristics.
Surgery removes the tumor and surrounding tissue through lumpectomy or partial mastectomy procedures. Full mastectomy may be chosen for large multiple tumors or high genetic risk. Sentinel lymph node biopsy injects dye near the tumor to identify nodes for removal. Radiotherapy typically runs five days per week for up to seven weeks after surgery. External beam radiotherapy focuses beams onto targeted body parts while brachytherapy places radioactive material at the surgical site. Chemotherapy reduces recurrence chances in the next ten years by around a third. Four to six cycles are given in two-to-three-week intervals with rest periods between treatments. Anthracyclines like doxorubicin cause congestive heart failure in around 1 percent of people treated. Taxanes induce peripheral neuropathy permanent in up to 5 percent of those treated. Trastuzumab antibodies reduce recurrence and death chances by at least a third for HER2-positive cases. Endocrine therapy blocks estrogen receptors reducing breast cancer death risk by around 40 percent over ten years. Tamoxifen treatment blocks ER while aromatase inhibitors chemically block estrogen production. Side effects include hot flashes vaginal discomfort and muscle joint pain lasting at least five years.
More than 90 percent of women survive breast cancer for at least five years in the United States UK South Korea Japan and Australia. China records an 82 percent survival rate while India sees only 66 percent. Overall 92 percent of women diagnosed in the US survive at least five years from diagnosis. Tumors confined entirely to the breast have 100 percent five-year survival rates for nearly two thirds of cases. Metastatic disease carries relatively poor prognoses with 33 percent surviving at least five years. Triple-negative breast cancer has an overall five-year survival rate of 78 percent but only 15 percent for metastases. Inflammatory breast cancer patients have an overall five-year survival rate of 40 percent dropping to 22 percent with metastases. Tubular mucinous or medullary growths tend to have better prognoses. Breast cancer before age 35 is rare and linked to genetic predisposition to aggressive forms. Cancer in those aged over 75 associates with poorer prognosis outcomes worldwide. Worldwide breast cancer resulted in 627,000 deaths in 2018 accounting for 2 million new cases.
Up to 80 percent of variation in frequency across countries stems from reproductive history impacting estrogen levels. Women beginning menstruation before age 12 or undergoing menopause after 51 face increased risk. Giving birth as a teenager reduces risk by around 70 percent compared to childless women. Breastfeeding lowers chance of developing cancer by approximately 4 percent per 12 months experience. Hormone replacement therapy doubles risk after six to seven years of combined progesterone-estrogen treatment. Drinking alcoholic beverages increases risk even among light drinkers consuming less than half one drink daily. Globally about one in ten cases caused by alcohol use remains the most common modifiable factor. Obesity causes 7 percent of cancers while diabetes accounts for 2 percent. Smoking tobacco raises relative risk by 35 to 50 percent in long-term smokers. Lack of physical activity links to about 10 percent of cases. Preventive measures include maintaining healthy weight reducing alcohol increasing activity and breastfeeding. These modifications might prevent 38 percent of cancers in the US and 42 percent in the UK. Removal of breasts before cancer develops reduces risk by more than 95 percent for genetically predisposed women.
The oldest discovered evidence dates back 4200 years to Egypt's Sixth Dynasty showing metastatic spread damage. The Edwin Smith Papyrus describes eight breast tumor cases treated by cauterization stating no treatment exists. Ancient medicine believed imbalances in black bile caused disease or viewed it as divine punishment. Mastectomy was performed at least as early as AD 548 when Aetios of Amida proposed it to Theodora. Jean Louis Petit performed total mastectomies including axillary lymph node removal in the early 18th century. Richard Wiseman documented mid-17th century results where only two of twelve patients were cured after surgery. Anne of Austria died in 1666 from breast cancer following treatments with hemlock juice and arsenic ointments. William Stewart Halsted started radical mastectomies in 1882 raising 20-year survival rates from 10 percent to 50 percent. Radical mastectomies remained standard care in the USA until the 1970s while Europe adopted sparing procedures in the 1950s. Betty Ford openly discussed treatment options in 1974 sparking public debate about surgical choices. In the 1980s thousands received high-dose bone marrow transplants proving completely ineffective killing 15 to 20 percent of women.
Breast cancer is the most common invasive cancer in women accounting for 30 percent of cases globally. Around one in 12 women diagnosed in wealthier countries compared to one in 27 in lower income nations. One in 71 women die of breast cancer in wealthy countries versus one in 48 in lower income countries. Black women aged 45 and older have higher incidence than white women yet are more likely to die at every age. The median diagnosis age for Black women is 59 compared to 62 in White women. Five-year survival rate reaches 81 percent in Black women and 92 percent in White women. Less than 3 percent of clinical trial participants identify as Black despite representing 12.7 percent of the national population. Low-income immigrant disabled and racial minority women less likely undergo screening receiving late-stage diagnoses. Pink ribbons became prominent symbols in the 1990s sold as fundraisers by US-based corporations. Critics argue pink ribbon campaigns distract from preventing curing disease while reinforcing gender stereotypes. Samantha King claimed in 2006 that breast cancer transformed into a market-driven industry of survivorship and sales.
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Common questions
What are the most common symptoms of breast cancer?
A new lump in the breast is the most common symptom of breast cancer though many people have no symptoms at diagnosis. Other physical changes include skin thickening known as peau d'orange swelling or dimpling of the skin and fluid coming from the nipple that may appear red or clear.
How effective is mammography for detecting tumors in dense breasts?
Mammography detects around 90% of tumors in fatty breasts but only 60% in extremely dense ones where dense breast tissue appears opaque on mammograms obscuring tumors. Women with dense breasts may use ultrasound magnetic resonance imaging or tomosynthesis instead to improve detection rates.
What percentage of breast cancers are ductal carcinomas?
Tumors arising from mammary ducts account for 85 percent of cases as ductal carcinomas while lobular carcinomas make up 10 percent derived from mammary lobes. Rarer types include mucinous carcinoma at 2.5 percent and tubular carcinoma at 1.5 percent.
Which countries have the highest five-year survival rates for breast cancer?
More than 90 percent of women survive breast cancer for at least five years in the United States UK South Korea Japan and Australia. Overall 92 percent of women diagnosed in the US survive at least five years from diagnosis compared to 82 percent in China and 66 percent in India.
How does reproductive history affect breast cancer risk levels?
Up to 80 percent of variation in frequency across countries stems from reproductive history impacting estrogen levels including menstruation before age 12 or menopause after 51. Giving birth as a teenager reduces risk by around 70 percent compared to childless women while breastfeeding lowers chance of developing cancer by approximately 4 percent per 12 months experience.
When did radical mastectomies become standard care in the USA?
William Stewart Halsted started radical mastectomies in 1882 raising 20-year survival rates from 10 percent to 50 percent. Radical mastectomies remained standard care in the USA until the 1970s while Europe adopted sparing procedures in the 1950s.