Three Years Ago, I Was Diagnosed With Cysts On My

Three years ago, I was diagnosed with cysts on my left breasts. Today, 2016 I noticied that my left breast is swollen. I did schedule a mammogram at my local imaging center for a diagnostic screen. There is no history of breast cancer in my family. Could this be a sign of breast cancer? I do have an appointment next week with the imaging center. ( I do not have a debit card right now)