20-39 • Breast Cancer Foundation NZ

Breast awareness

Taking care of your breasts in your twenties and thirties



The incidence of breast cancer increases as women age. Most breast cancers occur in women over the age of 50, but whatever your age, it’s important to be aware of any changes in your breasts, and if they persist, have them checked by your doctor.

Breast cancer in this young age group is uncommon. In fact, only 8% of breast cancer cases occur in women under the age of 40. While the risk of getting breast cancer is much lower for young women, the disease is sometimes more aggressive in this age group.

How do I take care of my breasts?

The best thing you can do to protect yourself is to be breast aware from the age of 20. This means knowing how your breasts normally look and feel and regularly checking for any unusual changes.

Your breasts may feel heavy or tender before your period, so the best time to check is after your period finishes, once any discomfort has settled down. Show your doctor if you have any unusual symptoms that don't go away after your period, particularly if you can feel a lump, or thickened tissue in your breast, or notice a discharge or any skin or nipple changes. Of course, most changes are not caused by breast cancer but it’s important to have any new changes properly checked.

Why can’t I have screening mammograms?

A mammogram is not recommended as a regular screening tool for women under 40 (unless they have a high risk of getting breast cancer).

This is because:

  • Breast tissue in this age group is naturally denser than in older women, meaning there is a greater concentration of glandular tissue versus fatty tissue in the breasts.
  • Glandular breast tissue appears white on a mammogram, as do cancers, so it can be difficult in this age group to detect small tumours.
  • This means young women might be subjected to unnecessary biopsies (false positive result) or cancers may be missed (false negative result).

Can I screen with ultrasound instead?

An ultrasound scan (which uses high frequency sound waves) is also not a reliable stand-alone method of breast screening in young women. It’s a useful targeted diagnostic tool for adding extra information when investigating a known abnormality, but it’s not accurate enough for generally scanning the breast and screening for cancer.

Lifestyle factors

You can reduce your lifetime risk of breast cancer by adopting healthy lifestyle choices while you are still young.

  • Be active. Regular exercise is associated with a decrease in the lifetime risk of breast cancer. Read the World Health Organisation’s exercise recommendations.
  • Maintain a healthy body weight. Women who are overweight or obese have a higher risk of breast cancer after menopause so it’s important to adopt healthy eating patterns early in life. Eat plenty of fruit and vegetables and stay away from junk food or make it only an occasional treat.
  • Limit alcohol. Alcoholic drinks raise the levels of oestrogen in the body and contribute to breast cancer risk.

Understand your family history

Talk with your family members about cancer on both sides of your family.

  • If your mother or sister has had breast or ovarian cancer before the age of 50, it’s recommended you get screened annually with mammogram and ultrasound, from 10 years prior to their age at diagnosis, but not earlier than 30 years of age.
  • Women at potentially high risk of breast cancer should be referred to a breast specialist for advice on appropriate screening
  • High-risk screening may also include breast MRIs.

While the risk of inherited breast cancer is low, talk about it with your doctor. If you are potentially at high risk, you may be eligible for genetic testing with Genetic Health Service NZ. This assessment would require a referral from your doctor.

Learn more about Family History and Risk.