It’s time to think about your breasts — not just this month because it’s Breast Cancer Awareness Month, but every month.

One in eight women will be diagnosed with invasive breast cancer in their lifetimes, according to the American Cancer Society. Breast cancer is the second leading cause of cancer death for women in the United States, with 42,000 women dying every year from this cancer.

These numbers are especially sobering because when breast cancer is caught in its earliest stages, the five-year survival rate is as high as 99 per cent. This is why screening is so important, including for younger women, whose rate of breast cancer diagnosis has been increasing in recent years.

Women need to know when to start screening for breast cancer. Besides a mammogram, should other tests be done? Who should begin screening earlier? Should women do self-exams, and if so, what should they be looking for? What kinds of normal changes should women expect in their breasts over time? Are there steps women can take to reduce their risk of breast cancer? And what should men do?

To help us answer these questions, I spoke with CNN wellness expert Dr. Leana Wen. Wen is an emergency physician and adjunct associate professor at George Washington University. She previously was Baltimore’s health commissioner.

CNN: When should women start screening for breast cancer?

Dr. Leana Wen: Most women should receive a mammogram beginning at age 40 every other year until they reach age 74, according to a recent US Preventive Services Task Force recommendation. (For those 75 and above, the task force concluded that there was insufficient evidence to recommend for or against mammography on a population level. Patients should discuss individual circumstances with their provider.)

This was a substantial change from earlier guidance, which was to start every other year mammograms at age 50. This change was made in part because of reports that cancer diagnoses have been increasing among younger people.

CNN: Should other tests besides the mammogram be done?

Wen: It’s important to separate screening from diagnosis. Screening is done when there are no symptoms. If someone has a positive screening test, additional studies may be done to further determine if this could be cancer.

Depending on the patient’s risk factors, they may receive additional screening tests. For instance, someone with multiple first-degree relatives with breast cancer may be recommended for genetic testing. An individual with prior abnormal results, or who otherwise has a higher risk of breast cancer, may have tests done in addition to the mammogram, such as a breast MRI or ultrasound.

In recent years, there has been a lot of debate among experts about whether younger women with dense breast tissue need these additional screening tests. The American College of Radiology now recommends a breast MRI in some women with dense breast tissue. The US Preventive Services Task Force did not make this recommendation, but this is something that patients can discuss with their physician.

CNN: Who should begin mammograms earlier than age 40? 

Wen: The recommendation to start at age 40 is for women at average risk of breast cancer. Those at higher risk include women with a sister, mother or other first-degree relative with breast cancer. People who have had breast cancer themselves are also at higher risk, as are individuals with prior radiation to the chest from treating other cancers. All these individuals should consult with their primary care provider to determine when they should begin screening, with which tests and at what frequency.

CNN: Should women do self-exams, and if so, what should they be looking for? 

Wen: According to the , research has not demonstrated a clear benefit of regular self-exams, especially when women are also getting screening mammograms.

That said, women can still pick up on changes they should report to their doctors. They should know how their breasts look and feel, and not delay seeking care if they notice unexpected changes.

The most common symptom of breast cancer is a new mass or lump. Many lumps turn out not to be cancer, but it’s crucial to get them checked out.

Other changes that should prompt women to contact their physicians include nipple discharge, pain or swelling, nipple turning inward and changes in color or the breast or nipple. They should also report swollen lymph nodes in the armpits or near the collarbone.

These changes are sometimes detected during daily activities, like showering, brushing hair and getting dressed. This, again, is why women should know how their breasts generally appear and feel, so that they can be on the lookout for any changes.

CNN: What kinds of normal changes should women expect in their breasts over time? 

Wen: There are multiple changes that occur in breast tissue over the course of a woman’s lifetime. During puberty, breasts become larger, and the nipple becomes raised. Women who become pregnant experience significant changes before, during and after pregnancy. Many pregnant individuals report breast swelling, soreness and nipple tingling. Blood vessels in the breasts become more visible and the nipple larger and darker.

Many women report that their breasts appear different after childbirth, even after breastfeeding has stopped. Then there are changes that occur as they enter menopause. Breast tissue tends to shrink and lose elasticity.

These are all normal changes that occur as women go through different life phases. Breast size and texture also change slightly during the menstrual cycle. All of this should underscore why women need to be aware of their bodies so that they can be aware of problems that may arise at different points in their lives.

CNN: Are there steps women can take to reduce their risk of breast cancer?

Wen: Risk factors like family history or cancer history cannot be altered, but there are some that can. Quitting smoking and reducing alcohol consumption, for example, can remove two key risk factors for breast cancer (smoking and heavy alcohol use). Getting regular physical activity can also lower overall cancer risk, as can a nutritious diet with less ultraprocessed substances.

CNN: Can men get breast cancer?

Yes. We have been referring primarily to women because breast cancer is far more common among women. However, there are men who are diagnosed with breast cancer as well.

Men who have significant breast cancer history in their family should speak with their physician about screening recommendations and not hesitate to seek care if they notice breast changes.

In addition, all people assigned female at birth should follow recommendations for breast cancer screening as noted above. That includes not only cisgender women but also transgender men and nonbinary people.