Breast cancer risk for women under 40.

A breast cancer diagnosis under 40 is rare.  Only 4% of breast cancer cases in the UK occur in women under 40. This percentage is the same for men also (CRUK). 

If you’re under 40, what may increase your risk? 

• Young women who get breast cancer are more likely than older women to carry a known genetic mutation associated with increased risk, such as a BRCA mutation; they are also more likely to have a family history of breast cancer. 
• Having high breast density is another important risk factor. 
• Starting periods before age 12, being tall, and having certain types of benign breast disease also increase risk. 
• Taking the combined contraceptive pill can slightly increases the risk, however this can depend on the type you take and how long you take it for – discuss your options with your GP if you have any concerns. 
• First pregnancy in those 30 years of age or younger reduces the long-term risk of breast cancer. However, pregnancy at any age increases short-term risk. Women whose first pregnancy occurs after the age of 35 have a long-term increased breast cancer risk. 
• Other factors that increase risk at any age include a previous diagnosis of breast cancer, alcohol consumption, lack of physical activity, and exposure to hazardous chemicals such as carcinogens or endocrine-disrupting chemicals such as bisphenols found in certain plastics. 

Sadly, not all breast cancer cases are preventable, and there are women (and men too) who will be diagnosed with a cancer that can’t be prevented, but studies have shown that by making changes to your lifestyle, you can reduce your chances of getting breast cancer significantly. 

Tips to reduce your risk of breast cancer 

• Establish healthy eating patterns, which include eating a high proportion and variety of fresh fruit and vegetables and limiting the amount of processed food you eat. 
• Limit the amount of alcohol you drink; the less you drink, the more you reduce your risk of breast cancer. 
• Exercise regularly; as a minimum, follow WHO guidelines. 
• We know that family planning can be a complex and emotional subject, but from a breast cancer risk perspective, if you’re considering having children and can, trying to have them before you’re 30 can reduce risk. 
• Try to breastfeed if possible. 
• Minimise use of cosmetics and personal care products, especially those that contain endocrine-disrupting chemicals. 

For more information on how making healthy choices can help reduce your risk of breast cancer, please read our Health and Lifestyle section.