How can young women find breast cancers early, if mammograms aren't done until they are older?

Breast self exam. Breast cancer is rare in young women, but not impossible. It is good to be comfortable knowing what are normal "lumps and bumps" for you and how your breast change during your menstural cycle. If you notice a lump that is new or diffferent, or any nipple bleeding or discharge, bring it to your dr.'s attention asap. Most woment find their own masses. Be comfortable performing a breast self exam.
Exam, 'Gram, MRI. Thankfully, breast cancer is rare in young women, which explains why we begin screening at 40. Although controversial, I am a proponent of self-examination and have cared for many women who have found their own cancers. If you have a strong family history of breast cancer, we begin mammography 10 years before your relative was diagnosed. An MRI can be very helpful in young women with dense breasts.
Self exam, doctor. Exam. Knowing your body (breasts for women; testes for men) is the first defense. Mamograms at young age deliver radiation more likely to cause problems than find them. Mammos rarely find the 15% of cancers called lobular carcinoma. Examine yourself during all phases of menstrual cycle to see normal variations. Call your doc if you find a change.