Date: 08/23/18
Source: medscape.com
Author: Nick Mulcahy

Oropharyngeal squamous cell carcinoma (SCC) is now the most common HPV-associated cancer in the United States, according to a new report from the Centers for Disease Control and Prevention (CDC) that covers the years 1999 to 2015.

During that period, cervical cancer dropped from being the top HPV-associated cancer and oropharyngeal SCC took its place.

The transition happened because cervical carcinoma incidence rates decreased 1.6% per year, and oropharyngeal SCC incidence rates increased 2.7% per year among men and 0.8% per year among women.

In 2015, there were a total of 11,788 cervical cancers compared with 18,917 oropharyngeal SCCs.

The decline in cervical cancer is a “continued trend since the 1950s as a result of cancer screening,” write the report authors, led by Elizabeth Van Dyne, MD, MPH, an epidemic intelligence service officer at the CDC.

The uptick in oropharyngeal SCC could be due in part to “changing sexual behaviors,” including unprotected oral sex, especially among white men, who report having the highest number of sexual partners and performing oral sex at a younger age compared with other racial/ethnic groups, the authors say.

Oropharyngeal SCCs include those at the base of tongue, pharyngeal tonsils, anterior and posterior tonsillar pillars, glos­sotonsillar sulci, anterior surface of soft palate and uvula, and lateral and posterior pharyngeal walls.

The new report was published August 24 in the Morbidity and Mortality Weekly Report.

The study authors defined HPV-associated cancer as “an invasive malignancy in which HPV DNA was frequently found in special studies.” In other words, the new study data reveal the total number of certain cancers that are associated with — but not necessarily caused by — HPV.

A total of 30,115 new cases of HPV-associated cancers were reported in 1999 and 43,371 in 2015.

Overall, the rate of HPV-associated cancers dropped among women (change, –0.4%) during the study period and rose among men (change, 2.4%).

The CDC analyzed data from their National Program of Cancer Registries and the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program for all years from 1999 to 2015. “These data cover approximately 97.8% of the US population,” say the authors.

However, these two population-based cancer registries have a limitation: They tally invasive cancers but not the HPV status of cancers.

The authors point out HPV causes cervical cancer and “some oropharyngeal, vulvar, vaginal, penile, and anal cancers.”

Table. Annual Change in Type of Cancer From 1999 to 2015

Cancer Type Average Annual Change (%)
Cervical –1.6
Vaginal –0.6
Oropharyngeal in men 2.7
Oropharyngeal in women 0.8
Anal in men 2.1
Anal in women 2.9
Vulvar 1.3

Penile cancer rates remained stable during the study period.

The study authors say that the public health implication of the study is that HPV vaccination “can prevent infection with the HPV types most strongly associated with cancer.”