The author of this article is Dr. R. Sankaranarayanan, Director, Preventive Oncology, Karkinos Healthcare
Cervical cancer is a type of cancer that occurs in the covering cells of the lower part of the uterus called cervix that connect both to the vagina and the body of the uterus. It is a very common cancer among poor women in low- and middle-income countries (LMIC). WHO-IARC estimates that 604,000 new cases and 342,000 cervical cancer deaths occurred in 2020 globally of which more than 95% occur in LMICs. Cervical cancer accounted for 124,000 new cases and 77,000 deaths in 2020 in India. Worldwide cervical cancer is the fourth most common cancer preceded by breast, large bowel and lung among women and in India the second most common cancer in women.
What causes cervical cancer?
Cervix cancer is caused by persistent infection of the female lower genital tract (cervix, vagina, vulva) by one of the 14 types of the Human Papillomavirus (HPV). It is the most common, ubiquitous viral infection of the lower genital tract.
Among the HPV types implicated in cervical cancer causation, HPV 16 and HPV 18 account for 70-80% of cervical cancer cases. All most all women get infected with one or more of the HPV after sexual debut; fortunately HPV infection clears by itself in more than 90% of the infected women. Thus when exposed to HPV infection, the body’s protective immune system clears these viruses in most women thereby preventing the virus from doing harm.
Although HPV infection is very common, and most women with the virus never develop cancer which indicates other factors such as poor nutrition, and other environmental or lifestyle factors also determine whether women with HPV infection develop cervical cancer. Most HPV infections clear up on their own and most pre-cancerous lesions resolve spontaneously, nevertheless there is a risk for all women that HPV infection may become chronic and cause pre-cancerous lesions that might progress to invasive cervical cancer. It takes 15 to 20 years for cervical cancer to develop in apparently healthy women whereas it might take only 5 to 10 years in women with weakened immune systems, such as those with untreated human immunodeficiency virus (HIV) infection. Women living with HIV are six times more likely to get cervical cancer compared to women without HIV infection.
Prevention of cervical cancer
Cervical cancer is an eminently preventable disease and amenable for elimination, provided women are vaccinated against HPV infection and screened with one of the screening tests such as HPV testing, Pap smear or visual inspection with acetic acid (VIA) for early detection of precancerous lesions such as CIN and AIS at appropriate ages and their effective treatment. Even invasive cervical cancer in symptomatic women can be detected in early clinical stages such as stages I A, I B and IIA which can be effectively treated with surgery or radiotherapy with cure rates ranging between 85-95%. Thus early diagnosis of symptomatic cervical cancer cases and adequate treatment may substantially avoid cervical cancer deaths. If the above interventions are provided to a large number of women in the community, the incidence of cervical cancer can be prevented substantially.
Is it possible to eliminate cervical cancer?
It is possible to reach and maintain an incidence rate of 4 per 100,000 women or less by vaccinating 90% of the girls with two doses of human papillomavirus (HPV) vaccination separated by 6-12 month interval before they reach 15 years; and screening 70% of adult women aged 30 years and above using a highly accurate test such as testing for HPV infection and treating adequately screen positive women found with precancerous lesions (stage 0).
In addition, early diagnosis and adequate treatment of cervical cancer with surgery or chemo radiotherapy can cure a large proportion of early stage (stages I and II A) cervical cancer patients. It is critical that more than 90% of women detected with cervical precancerous lesions or cancer should receive adequate treatment well in time.
Challenges in cervical cancer elimination
Lack of political will, national plans for elimination and commitment of resources for cervical cancer prevention in many LMICs is a major challenge. Unaffordable HPV vaccine costs, vaccine hesitancy and vaccine misinformation substantially limit the scope of introduction of elimination programs. Vaccine misinformation, particularly on its safety, unfounded fears on both short- and long-term side effects, vaccine costs and unaffordability for most people and the long latent period for its efficacy to become obvious seem to be the main factors responsible for vaccine hesitancy. Widespread future availability of Indian and other LMIC HPV vaccines will mitigate vaccine costs, access and affordability constraints to a large extent.
The unprecedented reallocation of healthcare services necessitated by the COVID-19 pandemic across high-, middle-, and low-income countries, coupled with staff shortages and capacity constraints, is likely to hamper cervical cancer elimination efforts globally with delays in elimination of cervical cancer.
Around the world, one woman dies of cervical cancer every two minutes and without action, cervical cancer cases will increase by 50% in 2030. Cervical cancer elimination efforts may be equated to steps to eliminate one of the world’s public health failures. Although we have the opportunity, know-how and prevention methods to avoid cervical cancer cases and deaths, these methods have not reached everyone in need. The vision of a world without cervical cancer requires consistent advocacy, improved awareness in all segments of the society, a time bound elimination plan, resource allocation, building infrastructure, augment trained human resources and monitoring and evaluation.