Updated

Breast cancer is a malignant tumor that begins in breast tissue and spreads throughout the body. According to Susan G. Komen for the Cure, an estimated 226,870 new cases of invasive breast cancer will be diagnosed in 2012. Chandini Portteus, vice president of research at Susan G. Komen for the Cure, says that  breast cancer was originally thought of as just one disease, but now it's known that it comes in many different forms with different outcomes.

Invasive and non-invasive breast cancer
There are two types of breast cancer. Invasive breast cancer begins in the milk-producing ducts or the lobules (milk glands) and extends into the nearby tissue. This can eventually stretch throughout the body to the bones, liver and lungs. Non-invasive breast cancer grows inside milk ducts; it does not extend to nearby tissue but can develop into invasive breast cancer.

Causes
Breast cancer is most likely caused by a combination of genetics and environment, although the specifics remain unclear to scientists.

Lauren Bowling, an expert in genetic counseling at Loyola University Medical Center, says 15 to 20 percent of breast cancer is familial, meaning there may be a combination of shared genes as well as diet and lifestyle factors within a family that make "breast cancer more common in some families than others."

Breast cancer occurs when the genes responsible for regulating healthy cell growth mutate. This spurs an abnormal cell growth that accumulates and spreads throughout the breast, resulting in a tumor.

Older women are more likely to get breast cancer but it can happen in young women as well. Caucasian women are at greater risk of getting breast cancer than any other ethnic group, but African American woman are more likely to die from it. Approximately one in every 100 cases of breast cancer occurs in men.

Symptoms
The American Cancer Society reports that the most common symptom of breast cancer is a new lump. Other common symptoms include swelling, skin irritation, nipple retraction or pain, redness, scaliness and nipple discharge.

Beginning around age 20, you should administer a breast self-exam once per month to familiarize yourself with your own breasts and search for changes. If you are over 40 years of age you should have a mammogram and physical exam once per year.

Diagnosis
No two breast cancers are identical, so doctors administer a series of tests on the tissues to better understand the nature of the breast cancer. This includes imaging tests (diagnostic and digital mammograms, MRI scans, ultrasounds and ductograms). If the imaging tests reveal possible cancer, the doctor will perform a biopsy.

Treatment
Since all breast cancers are different, they require different treatment regimens that should be determined by your doctor.

Portteus explained that we have cures for a vast majority of early stage breast tumors. "When breast cancer is caught at its earliest stages, a woman's chance of survival is 99 percent. That is a remarkable increase from where we were decades ago."

There are two common types of surgery designed to remove the tumor from the breast: lumpectomy and mastectomy. In a lumpectomy, the tumor and some surrounding normal tissue are removed. In a mastectomy, the entire breast is removed. Breast reconstruction can be performed immediately after a mastectomy, afterward or not at all.

Radiation therapy uses high-energy X-rays to kill the cancer cells. Chemotherapy uses drugs to kill the cancer. Hormone therapies block the tumors from accessing the hormones they need to grow.

For more information visit the Breast Cancer Research Foundation, the National Breast Cancer Foundation or Susan G. Komen for the Cure.