Cervical cancer is a tumour of the cervix, the junction between the uterus and vagina in the female reproductive tract. Certain types of human papillomavirus (HPV) are implicated in more than 90% of these cancers, although the great majority of HPV infections of the cervix are not associated with cancer. HPV is transmitted by vaginal sex, infecting cervical epithelial cells. In 5–10% of cases, infection persists for years, and pre-cancerous changes called cervical intraepithelial neoplasia can develop. These can regress, but sometimes progress to cancer. Although in nearly all forms of the cancer, HPV infection is considered essential for cancer to develop, other risk factors are involved, including smoking, HIV infection and other forms of immune suppression.
Cervical cancer is the fourth most common cancer in women worldwide. It can be detected by screening; screening every 3–5 years, with appropriate follow-up, can reduce cancer incidence by up to 80%. HPV vaccines protect against types 16 and 18, which cause three-quarters of cancers. Where screening and vaccination are not available, cervical cancer has substantial mortality; worldwide, an estimated 528,000 cases and 266,000 deaths occurred in 2012, with 80% of these being in developing countries.
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