Is it possible for a teen to get cancer?

In a fifteen year old the 2 most common causes of lumps are cysts and fibroadenomas which are benign (not cancer). It is very unusual for cancer to occur in women under 20. Cysts can be affected by menses and are often tender to the touch. Often they will decrease in size after your period. Even though cancer is unlikely it would be a good idea to have this checked by your doctor if it does not go away after your period. Sometimes these benign lumps still need removal if they are large enough.