|Year : 2019 | Volume
| Issue : 1 | Page : 1-2
Prevention of cervical cancer: Role of vaccination and screening
Priyanka Priyadarshini1, Saroj Kumar Das Majumdar2, Dillip Kumar Parida2
1 Department of Obstetrics and Gynaecology, Calcutta National Medical College and Hospital, Kolkata, West Bengal, India
2 Department of Radiotherapy, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
|Date of Web Publication||3-May-2019|
Dr. Priyanka Priyadarshini
Department of Obstetrics and Gynaecology, Calcutta National Medical College and Hospital, Kolkata - 700 014, West Bengal
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Priyadarshini P, Majumdar SK, Parida DK. Prevention of cervical cancer: Role of vaccination and screening. Oncol J India 2019;3:1-2
|How to cite this URL:|
Priyadarshini P, Majumdar SK, Parida DK. Prevention of cervical cancer: Role of vaccination and screening. Oncol J India [serial online] 2019 [cited 2019 Jul 18];3:1-2. Available from: http://www.ojionline.org/text.asp?2019/3/1/1/257615
Cervical cancer among all the female malignancies is a major part of morbidity and mortality, particularly in the developing countries. However, it is nearly a preventable disease, and diagnosis at the preinvasive stage can be possible.
Globally, the burden of cervical cancer is high among gynecological malignancies and is the fourth most common after breast, colorectal, and lung cancers among females. Annually, approximately 527,600 new cases of cervical cancer with 265,700 deaths were estimated in 2012. In low- and middle-income countries, it is the second most common cancer in incidence among women and the third most common in terms of mortality. Approximately 85% of new cases and 90% of deaths occur among poor socioeconomic populations and low-resource regions of the society.
Although most cervical cancers are due to human papillomavirus (HPV) infections, smoking cigarettes, using oral contraceptives, and having a weakened immune system are the other risk factors. The development of cervical cancer is usually a slow process through the phase of dysplasia, and later, cancer cells develop and spread into the cervix and surrounding tissues. Cervical dysplasia usually occurs in women in their 20s and 30s.
With this background, identification of high-risk populations and their screening and application of appropriate management are crucial for the prevention of cervical cancer. The incidence of cervical cancer can be controlled based on primarily prevention of invasive cancer by HPV vaccination and secondarily screening for precancerous lesions.
Persistent HPV infection with high-risk strains causes majority of cervical cancers and some anal, vaginal, and oropharyngeal cancers. HPV16 and HPV18 account for majority of cervical cancers, i.e., 71%, whereas other HPV types 31, 33, 45, 52, and 58 account for the rest 19% of cervical cancer cases. More than 80% of women will acquire at least one high-risk HPV infection during their lifetime, suggesting the ubiquitous nature of the HPV infection. The estimated cross-sectional HPV prevalence among healthy women is around 11.7% worldwide, and country-specific prevalence ranges 2%–42% globally, whereas age-specific HPV prevalence peaks at 25% in women aged <25 years, suggesting predominantly transmission of an infection through the sexual route. Thus, prophylactic HPV vaccination should target women before initiation of sexual activity, i.e., aged 10–14 years. At present, three types of HPV vaccines are available, such as a bivalent vaccine, targeting HPV16 and HPV18; a quadrivalent vaccine, targeting HPV6 and HPV11 in addition to HPV16 and HPV18; and a nonavalent vaccine, targeting HPV types 31, 33, 45, 52, and 58 in addition to HPV6, 11, 16, and 18. Anogenital warts caused by HPV6 and 11 can be prevented by the last two vaccines. HPV vaccination reduces the prevalence of high-risk HPV types, and reduction in anogenital warts and high-grade cervical abnormalities among young women is found. Vaccination prevents up to 70% of HPV-related cervical cancers as well as 90% of genital warts. In vaccination schedule, patients younger than 15 years need only two doses instead of three, and the vaccine can be used in adults up to the age of 45 years.
Approximately 90% of HPV infections are not detectable within 2 years of the acquisition of infection. It may be completely cleared or may remain latent in basal cells with the potential for reactivation. Women with persistent infection could develop cervical precancerous lesions. Therefore, detection of precancerous lesions and their appropriate treatment is crucial.
Although vaccination is the primary prevention, screening for cervical cancer is important and it prevents cancer by detection and treatment of precursor lesions, i.e., high-grade cervical intraepithelial neoplasia (CIN 2 and 3) and adenocarcinoma in situ. The screening strategy should be feasible, simple, safe, accurate, acceptable, and easily accessible to high-risk women. It is important to assess individual risk factors such as selection of screening method depending on patient age, screening history and results of the women, and resources available. Cervical cancer prevention strategies include interventions directed toward limiting the number of sexual partners, condom use, reduction in cigarette smoking, and vaccination.
Over the past few decades, a decrease in incidence for cervical cancer has been achieved due to development in the field of screening. Effective mass screening programs at a specific age group will detect precancerous lesions at an early phase and prevent progression into invasive cancer by appropriate treatment. Conventional cytology (Papanicolaou [Pap] smear), liquid-based cytology automated cervical screening techniques, visual inspection of the cervix after Lugol's iodine and acetic acid application, speculoscopy, cervicography, and HPV DNA testing are the different screening tests for cervical cancer. Exfoliative cervicovaginal cytology and Pap smear More Details are the gold standard screening strategies for cervical cancer. The accuracy of conventional cervical cytology has a sensitivity of 72% and specificity of 94%. Pap smear is the simple painless, reproducible, cost-effective, reasonably accurate test and sensitive tool to screen both nonneoplastic and neoplastic cervix lesions. Regular screening with the Pap test during the age range of 21 and 65 years decreases the chance of death of women from cervical cancer. As most of the premalignant and malignant lesions occur above the age of 40 years, Pap smear examination should be started in women at the age of 30–40 years.
Nowadays, in developed countries, screening is assessed by the combination of both cytology and HPV testing. HPV testing is done by DNA polymerase chain reaction or hybrid capture techniques, whereas in developing countries, the Pap test is useful as a screening modality. According to the 2001 Bethesda System, cervical epithelial cell abnormalities may originate in the squamous or glandular cells. It includes atypical squamous cells (ASCs) such as ASC of undetermined significance and ASC, cannot exclude high-grade squamous intraepithelial lesions (SILs), SIL such as low-grade SIL and high-grade SIL, and atypical glandular cells. Application of appropriate treatment for these lesions will prevent the development of invasive cervical cancer. Liquid-based Pap test is popular in developed countries, whereas conventional Pap test is the mainstay screening system in low-resource settings. The major constituent of cervical cancer mortality worldwide is from developing countries due to the absence of an efficient cervical cancer screening system. Therefore, it is important to know the overall scenario of epithelial cell abnormality in a developing country to counsel women and to organize a public health system for cervical cancer screening by Pap smear examination. Standard Pap smear reporting requires specimen adequacy, general categorization, interpretation, and results. Unlike developed countries, hospital-based data collections are essential to know the efficacy of the Pap test. Pap smear cytology-based screening is not well-organized enough in various developing countries, and cases being detected by the screening process are the symptomatic ones highlighting as a part of investigations related to the management of these patients. Therefore, it requires an extension of the cytological screening up to the primary health-care level, and if possible, HPV testing should be included. Training of medical and paramedical staff at the primary health center level is necessary to develop a cost-effective screening method.
It is important to undergo a risk-reducing surgery for women with inherited conditions after finishing childbearing. HPV vaccination should be offered for all girls and boys at the age of 11–12 years and the age range can be 9–26 years.
Therefore, cervical cancer can be eliminated in the foreseeable future by the judicious combination of both most up-to-date HPV vaccination recommendations and current cervical cancer screening guidelines, along with effective family and patient counseling that increase vaccination acceptance rates and follow-up protocols for abnormal cervical cancer screening results.
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