Cervical cancer is caused by HPV infection in 90% of cases and develops from pre-cancerous changes in the cervix, with risks including multiple sexual partners and smoking. Screening through Pap and HPV testing is important for early detection and treatment of pre-cancerous cells before cancer develops, with guidelines recommending Pap tests every 3 years for women ages 21-29 and co-testing with Pap and HPV tests every 5 years for women ages 30-65. Vaccines can protect against HPV but screening is still needed as other factors also contribute to cervical cancer risk.