Researchers from The University of Texas Health Science Center are calling for targeted public health interventions to reduce growing disparities in the rates of human papillomavirus (HPV)-associated cancers among people living in disadvantaged areas.
Their findings, published in JNCI Cancer Spectrum, showed that the incidence of anal and vulval cancers increased overall between 2000 and 2018 but the rate of increase was much higher in people from low-income US counties and areas with a high smoking-prevalence.
Oropharyngeal cancer rates also rose in these two groups, but perhaps most concerning was the fact that following years of decline, cervical cancer incidence began to increase by 1.6% per year among women from low-income counties from 2011 onwards.
Lead researcher Ashish Deshmukh, Ph.D., associate professor at The University of Texas Health Science Center at Houston School of Public Health, told Inside Precision Medicine that “the success of the widely implemented [cervical] screening program in the US (first introduced in the 1970s) and collective national efforts led to the decline in cervical cancer incidence; however, the incidence has unfortunately plateaued nationally in recent years. As we show in our study, when we further stratified the incidence by income level—in the lowest income counties, the incidence has started to increase, which is sobering.”
He suggests that decreasing cervical cancer screening rates could be one reason for this trend.
Using the Surveillance, Epidemiology, and End Results 21 database, Deshmukh and colleagues identified 252,648 HPV-associated cancers that were diagnosed between 2000 and 2018.
During this time, anal cancer rates increased by 3.2% and 3.9% per year, on average, among women and men, respectively, in the lowest quartile of county-level household income ($9,330 –$29,640). The corresponding average annual increases among those in the highest quartile of county-level household income ($39,410 –$82,930) were 2.6% and 1.5%.
The rate of vulval cancer increased by a mean 1.9% per year in the low-income group compared with 0.8% per year in the high-income group.
For oropharyngeal cancer, there was an average annual increase of 1.3% per year in women from low-income counties, but the trend was not linear, increasing until 2011 and then decreasing. In men from this group, the incidence increased by a steady 2.1% per year on average. In the high-income groups, the rate of oropharyngeal cancer remained stable over time in women (0.1% average annual increase) and increased by 1.7% per year in men overall but began to fall during the last 3 years of the study.
Deshmukh said that “it is unclear what may have contributed to greater and more rapidly rising incidence rates HPV-associated in low-income counties. However, we have a few hypotheses— smoking rates are generally high in low-income counties (which is a risk factor for these cancers) that may have contributed to the rapid rise.”
Indeed, when the researchers analyzed the data by smoking prevalence they saw a similar pattern of results.
Deshmukh also noted that low-income counties “overall have low HPV vaccination coverage.” He said that in 2020 overall HPV vaccine coverage in the US was 62% among females and 56% among males, but this can be “at least 10% percentage points lower” for people in low-income counties.
Unfortunately, Deshmukh believes that the disparities his team identified may worsen in coming years, particularly because cervical cancer screening and HPV vaccination rates fell during the COVID-19 pandemic and have not yet fully recovered.
He therefore says that “to reduce growing disparities in our society” the study “calls for national and collective efforts to improve HPV vaccination coverage and cervical cancer screening rates […] particularly in low-resource counties.”
