The Prevention of Cervical Cancer

Abstract

There are 500,000 new cases of cervical cancer every year, and about 84% of them occur in developing countries. Fifty-six percent to ninety percent of these women present late with FIGO stage III or IV. All cervical cancers are attributable to genital Human Papilloma Virus (HPV) infection, and the introduction of HPV vaccine has raised the potential for significant reduction in worldwide incidence of HPV infection and cervical cancer. The HPV vaccines are bivalent (active against HPV 16 and 18) or quarivalent (active against HPV 6, 11, 16 and 18). HPV type 16 and 18 accounts for 75% of cervical cancer. In HPV naive women, both vaccines are over 99% effective in preventing precancerous lesions and subsequently cervical cancer associated with HPV type 16 and 18. The objective of HPV immunisation programme is to provide three doses of the vaccine to girls before they reach the age when the risk of HPV infection increases, but vaccination programmes are very low and variable in sub-Saharan Africa. It is estimated that vaccination of 58 million 12-year old girls before the start of sexual activity worldwide will prevent 690,000 cases and 420,000 deaths related to cervical cancer at a cost of US$4 billion. Seventy percent of cancers prevented, and 75% of deaths, will be in low or lower middle income countries. Screening is essential, as early treatment of pre-cancerous lesions prevents up to 80% of cervical cancers in countries where screening is routine. However, screening implementation and utilisation is challenging in Africa because of poor infrastructure, long travel distances, lack of trained medical personnel, inadequate record keeping and delayed testing. Therefore, the WHO approved strategy for cervical screening in low resource countries is visual inspection with acetic acid (VIA) or with Lugol’s iodine (VILI). Despite their limited specificity both VIA and VILI are useful screening tools for low-resource settings because they are economical, and they provide immediate results. Research is going on in SSA about the feasibility and utility of HPV-DNA testing for cervical cancer screening, but in the short to medium term, HPV vaccination and VIA secondary screening will save many lives in SSA.