A modeling study led by researchers from Harvard T.H. Chan School of Public Health, has predicted that at current levels of human papillomavirus (HPV) vaccination and screening, cervical cancer could be eliminated (i.e. have cases reduced to fewer than four per 100,000 women) by 2038-2043 in the US. However, the researchers found that this process could be expedited by 10-13 years if screening coverage was increased to 90 percent. This scenario would avert over 1,000 additional cervical cancer cases every year.
Reporting in The Lancet Public Health, the team used two independent disease modeling platforms to compare nine different combinations of HPV vaccination and cervical cancer screening coverage with the “status quo” (current levels) of the practices. Although a rise in screening coverage brought the projected time of elimination forward, the same was not found of the HPV vaccination.
“Although HPV vaccination will be a major contributor to reducing cervical cancer over time, we found that in the immediate term, screening continues to play a critical role in reducing the burden of cervical cancer in the US,” Emily Burger, a research scientist in the Center for Health Decision Science at Harvard Chan School who co-led the study, said in a statement.
“Our findings do not suggest that efforts to increase vaccination coverage are unnecessary,” the authors clarified in the paper, “but rather that this approach is not the most expeditious method of reducing cervical cancer incidence in the USA because of the long time between acquiring an HPV infection and being diagnosed with cervical cancer (or other HPV-related cancers).”
Almost all cases of cervical cancer are caused by HPV. Passed on through sexual contact, the group of viruses is common. But of the 100 types of HPV, only a few can cause abnormal changes to the cells of the cervix, leading to cervical cancer. In 2018, an estimated 570,000 women were diagnosed with the cancer worldwide, and approximately 311,999 women died from the disease.
However, cervical cancer is one of the most preventable and treatable cancers, thanks to the HPV vaccination and early detection through screening.
Currently in the US, the researchers estimated around 75 percent of girls by the age of 26 are vaccinated, and 62 percent of boys have also received the HPV vaccine by the age of 21. For cervical screening, many women are under-screened and 14 percent are never screened at all, despite being advised to be tested every three years.
Having issued a call for the elimination of cervical cancer as a public health concern in 2018, the World Health Organization (WHO) has set global targets for 2030, including; 90 percent of girls HPV vaccinated by 15 years old, 70 percent of women screened twice in their lifetime, and a 90 percent rate of compliance for treatment.
Some countries are well on their way to achieving WHO’s elimination figure of fewer than four cases per 100,000 women, such as Australia. Even the US’s current rate of seven cases per 100,000 women isn’t too far from the mark.
One of the greatest concerns are women from low-income and lower-middle-income countries, who lack access to health services. They account for 90 percent of all cervical cancer deaths worldwide.
This study on the US is actually an extension of two previous studies published in The Lancet last week, which looked at the impact of HPV vaccination and cervical screening on cervical cancer elimination and the mortality impact of achieving the WHO’s targets, in 78 low-income and lower-middle-income countries.
Collectively, these studies showed that if the targets by the WHO are met, 72 million cervical cancer cases could be prevented in the next century, a drop of 97 percent. The possible eradication of cervical cancer was described as a “phenomenal victory for women’s health” by Professor Marc Brisson who co-directed the two former studies.