Last week I lamented that we can prevent so few cancers.  Cervical cancer screening is one of the success stories of prevention.  Regular pap smears can drastically decrease the risk of cervical cancer and makes death from cervical cancer virtually unheard of. Cervical cancer is a sexually transmitted disease, caused by human pappilomavirus (HPV).  Pap smears check for telltale changes in the cervix that happen after HPV infection.   Over many years these changes lead to cervical cancer. But w...