INTRODUCTION: CERVICAL CANCER SCREENING

Magnitude of the Problem Third most common cancer in women Affects 1.4 million women worldwide Each year, 460,000 new cases occur Each year, 231,000 women die of the disease About 80% of new cases are in developing countries

Background 99.7% of cervical cancers directly linked to previous infection with human papillomavirus (HPV) Of more than 50 types of HPV that infect genital tract, 15–20 types linked to cervical cancer Four of these types are most often detected in cervical cancer HPV infections often cause no symptoms Most common signs of infection are small pink or red warts, itching and burning in genital area

Background (cont.) After woman becomes infected with HPV: Infection may remain stable Infection may regress spontaneously If cervix infected, may develop into low-grade squamous intraepithelial lesions (LGSILs), also called mild cervical intraepithelial neoplasia (CIN I) or early dysplasia

Background (cont.) For every 1 million women affected, 10% (100,000) will develop precancerous changes in cervical tissue: These changes are usually in women ages 30–40 About 8% of these women will develop precancer limited to outer layers of cervix (carcinoma in situ) (CIS) About 1.6% will develop invasive cancer unless CIS detected and treated

Background (cont.) Progression to cervical cancer from high-grade squamous intraepithelial lesions (HGSILs) usually occurs over 10–20 years Although rare, some precancer lesions become cancerous within a year or two

HIV/AIDS, HPV Infection, and Cervical Cancer 39.5 million people living with HIV/AIDS in 2006; almost half women Heterosexual contact main mode of transmission in new cases In HIV-infected women: HPV detected more frequently; resolves more slowly HPV-associated diseases more difficult to treat Progression of precancer accelerated

HIV/AIDS, HPV Infection, and Cervical Cancer (cont.) Cervical cancer screening important in this population Where HIV endemic, 15–20% women positive for precancer Cervical squamous cell cancer now an “AIDS-defining illness” Antiretroviral drugs improve quality of life; effect on progression of precancer not known

Risk Factors for HPV and Cervical Cancer Sexual activity before age 20 Multiple sexual partners Exposure to sexually transmitted infections (STIs) Mother or sister with cervical cancer Previous abnormal Pap smear Smoking Immunosuppression HIV/AIDS Chronic corticosteroid use

Age-Related Changes in the T-Zone: Puberty Columnar cells (red in appearance) are gradually replaced by squamous cells (pink in appearance). This is a slow process and continues throughout the reproductive years.

Preventing Cervical Cancer Preventing HPV infection will prevent cervical cancer No conclusive evidence that condoms reduce the risk of HPV infection, although they may provide some protection against HPV-associated diseases

Primary Prevention: Development of a Vaccine A vaccine would be the most effective way to prevent cervical cancer Vaccine would protect woman against only some types of HPV Vaccine would need to contain mixture of virus types At least two vaccines currently being tested

Secondary Prevention Women already infected should be screened to determine whether they have early, easily treatable precancerous lesions Pap smear is most well-established screening method Other screening methods: Visual screening HPV tests Automated cytology screening Pap smear, with its many steps, is problematic in low-resource settings

Screening: Visual Inspection with Acetic Acid (VIA) VIA is at least as effective as Pap smear in detecting disease VIA has fewer logistic and technical constraints Studies in South Africa, India and Zimbabwe in 1990s showed VIA as a good alternative to Pap smear Later studies confirmed that VIA is viable option for screening in low-resource settings

Value of VIA in Low-Resource Settings Can effectively identify most precancerous lesions Is non-invasive, easy to perform and inexpensive Can be performed by all levels of health care workers in almost any setting Provides immediate results that can be used to inform decisions and actions regarding treatment Requires supplies and equipment that are readily available locally

Links to Other Reproductive Health Services Linking cervical cancer screening and treatment to other services is essential and logical These services are usually separate, leaving women without access to care and contributing to women’s poor health status Cervical cancer prevention must be integrated with existing reproductive health care services

Links to Other Reproductive Health Services (cont.) District-based implementation of interventions will ensure that health services are available close to where people live Nurse or midwife who works in the community is usually the best person to provide community-based, appropriate, safe and cost-effective care