Cervical cancer begins when normal cells in the lower portion of the uterus change or mutate. They first become pre-cancerous. When pre-cancerous cells grow out of control, they may spread to nearby tissue, as well as other parts of the body, and if left untreated, they may grow into a mass, or tumor. The process of pre-cancerous cells developing into cancer often takes years. Cervical cancer is most frequently diagnosed in women between the ages of 35 and 55. It’s uncommon for cervical cancer to be diagnosed in women under age 20, while about 20 percent of cases are diagnosed in women older than 65.