4
By Brenda L. Mooney
MADISON, 
WI—Squamous 
cell 
carcinoma 
of 
the anal canal (SCAC) is relatively rare in the 
general population, accounting for only 2.5% of all 
gastrointestinal malignancies. 
In specific patient populations—i.e., those with 
human immunodeficiency virus (HIV) or endemic 
human papillomavirus (HPV)—it is a much greater con-
cern. People living with HIV (PLWH) are at increased 
risk for anal dysplasia and anal cancer development, with 
the risk of anal cancer compared to patients without HIV 
infection ranging from 25-fold to 35-fold in some studies 
to a 40% to 80% greater risk in others. 
Immunosuppression, especially with concurrent 
HIV infection, is an important amplifier of risk due to 
inhibition of primary HPV infection clearance.
Endemic HPV, meanwhile, has driven an increase in 
cases by about 3% a year.
Those factors alone would make SCAC a great 
concern for the VHA, which cares for the largest 
population of PLWH of any healthcare system in the 
United States, while also being a major provider of HPV 
care. Veterans have a disproportionately high burden 
of HPV-associated cancers compared to civilians, with 
much of the blame related to low vaccination rates, 
estimated as only 30.2% of female and 18.7% of male 
veterans. The VA’s healthcare system treats a significant 
number of HPV-related cancers, primarily head and neck 
(oropharyngeal) cancers.1
But there is another issue; anal cancer, as a gastrointes-
tinal cancer, is considered to have a presumptive connec-
tion for certain veterans serving in the Gulf War or in wars 
after Sept. 11, 2001. The areas, according to the VA’s clin-
ical pathway for anal cancer treatment, are Afghanistan, 
Djibouti, Egypt, Jordan, Lebanon, Syria, Uzbekistan or 
Yemen or for those serving in the Southwest Asia theater 
of operations—Iraq, Kuwait, Saudi Arabia, the neutral 
zone between Iraq and Saudi Arabia, Bahrain, Qatar, the 
United Arab Emirates, Oman, the Gulf of Aden, the Gulf 
of Oman, the Persian Gulf, the Arabian Sea, the Red Sea, 
and the airspace above these locations—or Somalia, on or 
after Aug. 2, 1990. 
As a result of the preponderance of risk factors among 
High Rates of HIV, HPV and 
Toxic Exposure Make Anal 
Cancer a Concern for Veterans
New Treatment Options Improve SCAC Outlook
Veterans are at especially high risk for squamous 
cell carcinoma of the anal canal (SCAC) because 
of high rates of human immunodeficiency virus 
(HIV) and human papillomavirus (HPV).  It also is 
one of the gastrointestinal cancers considered a 
presumptive service condition for those deployed 
to many areas in the Middle East and Africa.  The 
good news is that a new immunotherapy drug 
was approved last year for first-line treatment 
of adults with inoperable locally recurrent or 
metastatic SCAC with disease progression or 
intolerance to platinum-based chemotherapy.

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