Every month probably about 7-10 days before my period, i get brown bloody discharge that lasts for about 5 days. as i'm a teen, is it cervical cancer?

Unlikely: It is extremely unlikely that you have cervical cancer given your age. It's possible this is related to an infection, especially if its foul smelling. Also may just be small amount of bleeding that you are having between periods that is very light and this blood often appears brown. This occurs when the lining of your uterus is thicker than normal.