January is Cervical Cancer Awareness Month

A perfect opportunity to raise awareness about cervical cancer, options for effective screening, and HPV vaccination

By Kelly Holland, RN, Leslie Bradford, MD, MMP Division of Gynecology Oncology

In 1928, cytopathologist George Papanicolaou, presented “New Cancer Diagnosis”, a short manuscript outlining his theory that malignant cells, sampled from vaginal fluid, demonstrated certain, identifiable characteristics that distinguished them from benign, non-cancerous processes.1 Papnicolaou then partnered with pathologist Herbert Traut to further refine the process of performing and fixing the “smear”. Nearly a century later, the basic premise of the “Pap smear” - analysis of exfoliated cells - serves as the basis for large-scale cervical cancer screening.

With the institution of cervical cancer screening, the incidence of cervical cancer in the US has decreased by over 50%.2 Effective screening for cervical cancer has reduced the risk of death (mortality) by more than 80% among screened women.3

Globally, cervical cancer is the second most common cancer and second leading cause of cancerrelated mortality among women.4 While cervical cancer incidence and cancer-related mortality has decreased dramatically in high-income countries with national screening programs and/or robust healthcare infrastructure, 80% of cases occur in middle- and low-income countries lacking these resources. A well-organized program is an essential component of cervical cancer screening. Even in the US, black women over the age of 50 are disproportionately affected by cervical cancer, with an incidence of 12.4 cases per 100,000.2

There have been multiple studies demonstrating the pitfalls of current cervical cancer screening strategies in the US, reporting that 11% to 51% of women diagnosed with cervical cancer had never had prior screening, and 19% to 36% did not have screening between 3-5 years before their cancer diagnosis.2 Under-screened populations include women who have immigrated to the US, minorities, low socioeconomic status, women with multiple chronic conditions, and/or women lacking medical insurance.

The Role of HPV

Three decades ago, human papillomavirus (HPV) was discovered by Harold zur Hausen, a German virologist (2008 Nobel Laureate in Medicine), and colleagues. This has led to a rapid advancement and improvement in our understanding of the virus and its role in the development of invasive cervical cancer. Notably, the association between certain high-risk, or oncogenic, strains of HPV (hrHPV) and cervical cancer is now well established, with HPV infection implicated in over 99% of squamous cervical cancers.5

Papillomaviruses are ubiquitous. There are more than 100 HPV subtypes, but not all infections result in invasive carcinoma. For instance, HPV 6 and 11 are considered low risk subtypes that can cause condyloma. Other low risk strains include 42, 43, and 44. Fourteen high-risk subtypes have been identified that can cause cervical cancer, including types16, 18, 31, 33, 34, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68, and 70.

HPV testing compared to conventional cytology

HPV testing and typing as a primary method of screening is now recognized as an alternative to

Continued from previous cytology-only and co-testing (a pap plus HPV testing). While being implemented in Europe and Australia, the use of HPV testing as a primary mode of cervical cancer screening in the US has yet to come to fruition, although many speculate there will be upcoming changes to the US screening and treatment guidelines.

Currently, the American Cancer Society recommends that cervical cancer screening should begin at age 25. Those aged 25 to 65 should have a primary HPV test every 5 years. If primary HPV testing is not available, screening may be done with either a co-test that combines an HPV test with a Pap test every 5 years or a Pap test alone every 3 years. The American College of Obstetricians and Gynecologists (ACOG) and the US Preventive Services Task Force (USPSTF) recommend that screening for cervical cancer be performed every 3 years with cervical cytology only in women aged 21 to 29 years. This is because women under 30 are more likely to effectively clear an HPV infection and co-testing can result in unnecessary procedures for this young cohort of patients. For women aged 30 to 65 years, the USPSTF recommends screening every 3 years with cervical cytology alone, every 5 years with high-risk human papillomavirus (hrHPV) testing alone, or every 5 years with hrHPV testing in combination with cytology (co-testing). Not all insurance carriers cover primary HPV testing at this time, so check your plan and discuss with your healthcare provider which screening strategy is best for you.

Vaccination

We would be remiss to discuss cervical cancer and screening strategies without commenting on the critical role of vaccination. HPV vaccination is a means of primary prevention in women who receive it prior to onset of sexual initiation. Because HPV is a sexually transmitted virus, and the peak prevalence of HPV is approximately five years after the median age of sexual initiation, to be most effective, vaccination needs to occur prior to sexual initiation. Therefore the US Centers for Disease Control and Prevention (CDC) recommends HPV vaccination for males and females starting at age 11 to 12 [5]. Effective vaccination programs do work. As an example, Australia was the first country to introduce a publicly funded HPV vaccination program via school-based vaccination programs in 2007. This program achieved a 70% vaccination rate within the first year and has remained constant over a 10-year period [6]. Their data showed the prevalence of infection from HPV subtypes covered by the vaccine decreased, as did anogenital warts and cervical precancerous lesions. Australia is currently on track to eradicate cervical cancer by 2035.

Here in Maine, will 81% of women ages 21 to 65 have had a Pap test within the past 3 years, but only 45% of 13 year-olds in Maine are vaccinated against HPV. Even with a well-established healthcare infrastructure, our vaccination completion rate is suboptimal and lower than the national rate of 51% [7]. HPV vaccination will continue to change the landscape of cervical cancer cases and disease burden. While the Pap test has had an incredible impact on cervical cancer mortality, first as a smear and then as liquid based cytology, HPV testing has emerged as a more sensitive screening test with greater global applicability. We predict that population-based screening will shift to this model, as it has in Australia and Europe, resulting in a greater ability to protect against invasive cervical cancer. Coupled with HPV vaccination, the effect should be profound. Given the natural history of persistent HPV infection, screening women results in a reduction in death from cervical cancer within 5 to 10 years, but another generation of women will need to be vaccinated to see true eradication of this disease.

This is a PREVENTABLE cancer. Please join us in raising awareness to keep the women of Maine safe, healthy, and cancer free.

References: See link in full publication; Additional Resources: https://www.nccc-online.org/cervical-health-awareness-month/; https://foundationforwomenscancer.org/gynecological-cancers/gynecologic-cancer-types/cervical-cancer/ Someone You Love. Available at https://www.hpvepidemic.com/