Cancer of cervix

Abstract

Cervical cancer is the second most commonly diagnosed cancer and the third leading cause of cancer death among females in less developed countries. There were an estimated 527 600 new cervical cancer cases and 265 700 deaths worldwide. Nearly 90% of cervical cancer deaths occurred in developing parts of the world. The large geographic variation in cervical cancer rates reflects differences in the availability of screening (which allows for the detection and removal of precancerous lesions) and in human papillomavirus (HPV) infection prevalence. The most significant cause of cervical cancer is persistent papillomavirus infection. HPV is detected in 99% of cervical tumors, particularly the oncogenic subtypes such as HPV 16 and 18. For many years, the Papanicolaou (Pap) test has been the standard method for cervical cancer screening, reducing the incidence by 60%–90% and the death rate by 90%. However, the limitations of this cytology-based test are the sensitivity (> 50%) and significant proportion of inadequate specimens. More recently, an HPV test has been introduced as a screening tool as HPV deoxyribonucleic acid (DNA) is present in almost all cervical cancers and it has demonstrated higher sensitivity for high grade cervical intraepithelial neoplasia (CIN2þ) than that achieved by cytology in several studies. A pooled analysis of four randomized controlled trials of HPV-based cervical screening versus conventional cytology showed that HPV-based cervical screening provides 60%–70% greater protection against invasive cancer compared with cytology-based screening. Findings support HPV-based screening with triage at prolonged intervals, starting at age 30 year. Therefore, primary prevention of cervical cancer is now possible via immunization with highly efficacious HPV vaccines [II, A] and secondary prevention has gained impetus with the advent of sensitive HPV DNA testing to improve traditional Pap cytology screening programs [II, A].