CNN  — 

Anal cancer cases and deaths are rising dramatically in the United States, especially among older people and young black men, a new study says.

Researchers examined trends in anal cancer cases over about 15 years, and identified about 69,000 cases of anal cancer and more than 12,000 deaths during this time.

“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,” the study’s lead author, Ashish A. Deshmukh, an assistant professor at UTHealth School of Public Health, said in a statement. “Given the historical perception that anal cancer is rare, it is often neglected.”

Distant stage disease is when the cancer has spread to other parts of the body.

From 2001 to 2015, cases of the most common type of anal cancer increased by 2.7% per year, while anal cancer death rates increased by 3.1% per year from 2001 to 2016.

The study, published in the Journal of the National Cancer Institute, “gives numbers to a trend that seems to be happening over the last decade,” said Dr. Virginia Shaffer, a colorectal surgeon and associate professor in Emory University’s Winship Cancer Institute. “In that sense it gives us numbers to what we were already expecting.” Shaffer was not involved in the study.

Cancer linked to HPV

Anal cancer occurs where the digestive tract ends. It is different from colon or rectal cancer and most similar to cervical cancer.

The most common subtype of anal cancer is squamous cell carcinoma, caused by human papillomavirus, known as HPV.

Over 90% of cases of anal cancers are associated with HPV, according to the US Centers for Disease Control and Prevention.