Human Papillomavirus Infection and Cervical Cancer: Epidemiology, Screening, and Vaccination—Review of Current Perspectives

Abstract

Viral infections contribute as a cause of 15–20% of all human cancers. Infection by oncogenic viruses can promote different stages of carcinogenesis. Among many types of HPV, around 15 are linked to cancer. In spite of effective screening methods, cervical cancer continues to be a major public health problem. There are wide differences in cervical cancer incidence and mortality by geographic region. In addition, the age-specific HPV prevalence varies widely across different populations and showed two peaks of HPV positivity in younger and older women. There have been many studies worldwide on the epidemiology of HPV infection and oncogenic properties due to different HPV genotypes. However, there are still many countries where the population-based prevalence has not yet been identified. Moreover, cervical cancer screening strategies are different between countries. Organized cervical screening programs are potentially more effective than opportunistic screening programs. Nevertheless, screening programs have consistently been associated with a reduction in cervical cancer incidence and mortality. Developed countries have achieved such reduced incidence and mortality from cervical cancer over the past 40 years. This is largely due to the implementation of organized cytological screening and vaccination programs. HPV vaccines are very effective at preventing infection and diseases related to the vaccine-specific genotypes in women with no evidence of past or current HPV infection. In spite of the successful implementation of the HPV vaccination program in many countries all over the world, problems related to HPV prevention and treatment of the related diseases will continue to persist in developing and underdeveloped countries.

Uptake and determinants of cervical cancer prevention services among female college students in Kenya: A cross-sectional survey

“…The baseline sociodemographic characteristics are described in Table 1. The median (IQR) age of the participants was 21 (20,22) years. Figure 2 shows a box plot of the age of the participants.…”

“…About two-thirds (338, 63%) were sexually active. The media (IQR) age of sexual debut was 19 (18,20). Figure 2 represents a box plot of the age at sexual debut.…”

“…However, such interventions are only effective if delivered to the target population. Although, the progression of cervical cancer from HPV infection to invasive carcinoma can take about 20 years, thus providing adequate time for intervention (20), HIV increases this rate significantly, hence the need for prompt intervention among women living with HIV/AIDS (21). Furthermore, since HPV infection is acquired soon after sexual debut, targeting much younger population especially in high school and university may be necessary (22).…”

Evaluation of Oral Supplementation with a Casein Hydrolysate-based Formula to Favor the Clearance of HR-HPV Infections and their Derived Lesions

“…Screening programs differ by country, but are mainly based on the determination of the presence of the virus by viral DNA detection tests and the determination of intraepithelial lesions by cytology (Pap test). The positive HPV DNA test implies the presence of the virus in the sample, while the positive cytology implies an alteration or injury in the tissue [9].The morphology of squamous intraepithelial lesions caused by HPV in the lower anogenital tract is identical in all locations and in both sexes [10]. The Lower Anogenital Squamous Terminology (LAST) classifies the histological intraepithelial squamous lesions (SIL) associated with HPV in two grades, low-grade lesions (LSIL) and high-grade lesions (HSIL) [11].…”

“…Screening programs differ by country, but are mainly based on the determination of the presence of the virus by viral DNA detection tests and the determination of intraepithelial lesions by cytology (Pap test). The positive HPV DNA test implies the presence of the virus in the sample, while the positive cytology implies an alteration or injury in the tissue [9].…”