Breast cancer is the most common form of cancer among women, excluding skin cancers, affecting one in eight women at some point in their lives. In 2017, the American Cancer Society (ACS) estimated more than 316,000 women in the US were diagnosed with breast cancer, and more than 40,000 died from the disease.

So, what is it? Breast cancer is a disease in which atypical cells grow out of control, most often in the glands that produce milk or the ducts that carry it to the nipple. To best protect yourself, learn the signs, symptoms and risk factors, and get prompt care if anything looks—or feels—unusual.

Know the risk factors
Breast cancer appears to be caused by a combination of genetic and lifestyle factors, including:

• Age—older than 50
• Genetic mutations—BRCA1 and BRCA2 genes
• Family history—mother, sister, daughter or multiple relatives on mother’s or father’s side with the disease
• Onset of menstrual periods before the age of 12
• Dense breast tissue

Having these risks does not mean breast cancer is inevitable. Many women with known risk factors may never develop breast cancer, while some women with no risk factors get the diagnosis, according to the ACS.

Still, women can control some risk factors, like alcohol intake, weight, physical activity and cigarette smoking. “There’s actually pretty good data that shows a link between smoking and increased breast cancer risk,” says Alene Wright, MD, a general surgeon with the Medical Center of Trinity in Trinity, Florida.

There’s also reasonable data, according to Wright, that postmenopausal obesity—a body mass index above 29.9 after menopause—can increase your breast cancer risk. Why? Estrogen levels in overweight or obese women are higher.

“Fat cells increase estrogen in low levels even when your ovaries aren’t working anymore,” says Dr. Wright. “Many breast cancers are stimulated by estrogen.”

Because of the wide variability in who does—and doesn’t—develop breast cancer, it’s important to know the signs and report any changes to your doctor.

Recognize signs and symptoms you shouldn’t ignore
“I think the most important thing for women to know is sometimes there are no signs of breast cancer,” Wright says. Instead, lumps or changes are picked up on routine screening.

Some women do experience symptoms, like a breast lump that lasts longer than one menstrual cycle, a change in color or thickness of the skin on the breast or pain in any area of the breast.

See your doctor if you notice changes like:

• Nipple discharge when not nursing; discharge could include blood
• Flaky skin or redness, especially around the nipple
• Change in the size or shape of one breast
• Dimpling of breast skin
• Pulling in of the nipple

If you notice any changes between screenings, don’t hesitate to discuss them with your doctor, even if you were screened recently. Changes could be totally normal—or a sign of a cyst, infection or eczema—and your doctor can evaluate and determine whether your breast changes are cause for concern.

In addition to reporting new bumps and lumps, women should also get routine screenings. Regular mammograms can help detect cancer before symptoms appear. Early detection allows for easier treatment and a better prognosis.

Find the right screening schedule for you
Different institutions have varying recommendations on when to start getting mammograms.

• The U.S. Preventive Services Task Force recommends women at average risk get screened every two years from ages 50 to 74, leaving it to a woman’s discretion, along with the advice of her doctor, to start in her 40s. Women at higher risk may benefit from screenings in their 40s, the task force suggests.
• The ACS recommends women at average risk get annual screenings starting at age 45, or 40 is they prefer, and continue annual or switch to biennial mammograms at age 55. Women with certain risk factors—like a first-degree relative with a BRCA 1 or BRCA2 gene mutations—should have an MRI and mammogram annually starting at age 30.

Women should get screened as long as they’re in good health and expected to live at least 10 years, the ACS recommends.

Since recommendations vary, it’s crucial to speak with your doctor about the best screening schedule for you. Wright believes that earlier screenings are beneficial to her patients. “I would recommend that a woman with average risk—meaning no strong family history, no prior history of breast concerns or breast biopsies—start at age forty and have a mammogram once a year,” she says.

Given the various recommendations, why forty? That’s typically the age women start nearing menopause, says Wright. “And we know that breast cancers tend to be more common in women who are menopausal.”

The bottom line: Stay up-to-date on your screenings and don’t let a change in breast size, color or appearance go unreported. A prompt in-office evaluation can be pivotal to getting speedy treatment or allaying your concerns.

By Taylor Lupo