Number of Americans with anal cancer diagnoses and deaths soars despite availability of HPV vaccine
The number of new anal cancer diagnoses and deaths related to human papillomavirus (HPV) — the most common sexually transmitted infection — has increased dramatically among Americans over the last 15 years. It has more than doubled for people in their 50s and 60s, and this even though a simple vaccination can prevent the virus.
Researchers from The University of Texas Health Science Center at Houston (UTHealth) and other institutes found that anal cancer rates and deaths increased by nearly 3% every year, from 2001 to 2016, suggesting it may be one of the most rapidly rising causes of "cancer incidence and mortality."
The team analyzed data from all cancer registries in the US and identified 68,809 cases of anal cancer and 12,111 deaths from 2001 to 2016. Nearly 90% of anal cancers are caused by HPV, says the research team.
"Screening for anal cancer is not currently performed, except in certain high-risk groups, and the results of this study suggest that evaluation of broader screening efforts should be considered," says the senior author of the study Dr Keith Sigel, an associate professor of medicine at Icahn School of Medicine at Mount Sinai.
The researchers compared and categorized contemporary national trends in incidence of squamous cell carcinoma of the anus, which is a type of anal cancer caused by HPV, by stage at diagnosis, year of birth, and mortality.
The analysis shows that anal cancer diagnoses, particularly advanced stage disease, and anal cancer death rates had more than doubled for people in their 50s and 60s. Further, new diagnoses among black men born after the mid-1980s increased five-fold compared to those born in the mid-1940s, says the study published in the Journal of the National Cancer Institute, and funded by the NIH/National Cancer Institute.
"Given the historical perception that anal cancer is rare, it is often neglected. Our findings of the dramatic rise in incidence among black millennials and white women, rising rates of distant-stage disease, and increases in anal cancer mortality rates are very concerning," says Dr Ashish A Deshmukh, the study's lead author and an assistant professor at UT Health School of Public Health.
What is anal cancer?
According to experts, anal cancer occurs where the gastrointestinal tract ends and is different from colon or rectal cancer due to the cell type and location where cancer develops. "Cancer of the anus is most similar to cervical cancer, a cancer of the tissue that lines a woman's cervix. A distant-stage diagnosis means that cancer has spread to other parts of the body, decreasing survival rates," says the study.
The US Centers for Disease Control and Prevention (CDC) estimates that each year, about 44,000 new cases of cancer are found in parts of the body where human papillomavirus (HPV) is often found. HPV causes about 34,800 of these cancers, says CDC.
"About 6,810 people are diagnosed with anal cancer each year, and about 91% of anal cancers are thought to be caused by HPV. 91% of 6,810 is about 6,200," says CDC.
Fighting the stigma
When 'Desperate Housewives' actress Marcia Cross recently revealed that she had anal cancer, she said she was doing so to battle the shame associated with the disease. However, the researchers contend that anal cancer is often neglected and stigmatized, despite high-profile deaths such as actress Farrah Fawcett of 'Charlie's Angels' fame as well as Cross's revelation about her diagnosis.
"It is concerning that over 75% of US adults do not know that HPV causes this preventable cancer. Educational campaigns are needed to increase awareness about the rising rates of anal cancer and the importance of immunization," says Deshmukh.
The virus is preventable through vaccination, but 50% of Americans are not vaccinated, setting up a potential wave of future infections leading to cancer, says the team. The CDC recommends a two-dose regimen for children starting the series before age 15 or a three-dose regimen if the series is started at age 16 through 26.
"The vaccine can also be considered for individuals ages 27 to 45 based on shared decision-making, so it is important that adults speak with their healthcare providers about getting the vaccine," says Deshmukh.