Most breast cancers are found before symptoms appear
Breast cancer arises in breast tissue and may announce itself with a lump, shape change, skin dimpling, or nipple fluid—yet many cases have no symptoms when screening finds them. Five-year survival exceeds ninety percent in the United States and United Kingdom.
Breast cancer is the most common cancer in women worldwide, making up a quarter of all their cases; in 2018 it brought about two million new diagnoses and 627,000 deaths. It is more frequent in developed countries. Recognised risks include obesity, inactivity, alcohol, hormone replacement during menopause, radiation, early first periods, late or no childbearing and older age. Only around five to ten percent of cases stem from inherited predisposition such as BRCA mutations.
Many patients feel nothing at all when a scan catches the disease. When there is a sign, a new lump is the usual one, though most lumps turn out harmless; hard, painless lumps with ragged edges are the more worrying kind. Rarer forms announce themselves differently. Inflammatory breast cancer, up to 5 percent of cases, blocks lymph vessels so one breast swells and reddens over three to six months, and Paget's disease, up to 3 percent, looks like eczema on the nipple.
Screening works by finding tumours while they are small and contained. Mammography squeezes each breast between plates for a low-dose X-ray and spots dense masses or tiny calcium flecks. Its sensitivity falls with tissue density: about 90 percent of tumours are caught in fatty breasts but only 60 percent in extremely dense ones, where ultrasound, MRI or tomosynthesis can help. Regular mammograms cut breast cancer deaths by at least 20 percent, and most guidelines advise yearly screening from 50 to 70.
After a biopsy, pathologists classify the tumour. About 85 percent are ductal carcinomas from the lining of the milk ducts. Tests for oestrogen and progesterone receptors and for HER2, present in roughly 15 to 20 percent of tumours, decide whether hormone or targeted drugs will work. Treatment ranges from breast-conserving surgery to mastectomy, plus radiation and chemotherapy, and high-risk women may take tamoxifen or raloxifene preventively.
Source: Breast cancer
