HIV-positive women are three times more likely than other women to develop
lesions that can lead to anal cancer, new research shows. The greater risk is
due at least in part to weakened immune defenses against the common sexually
transmitted human papillomavirus (HPV).
The research findings by scientists at the University of California, San
Francisco are published in the June 6 issue of the Journal of the National
“HPV already has been shown to increase risk of developing cervical cancer, but
our research shows HPV also increases abnormal development of anal cells that
may lead to anal cancer in women,” said Elizabeth Holly, PhD, MPH, lead author
of the study and UCSF professor of epidemiology and biostatistics.
Senior author on the study is Joel Palefsky, MD, UCSF professor of laboratory
medicine and stomatology, who, along with the other authors on this paper, has
made similar findings regarding HIV-positive men.
The researchers conclude that HIV-positive women may benefit from anal exams
and assessments of anal cells, although further research is needed. Those with
abnormal lesions should be carefully followed up, they say.
In the study, higher rates of anal cancer precursor cells were found in
HIV-positive women with anal HPV infection, lower CD4 cell counts (a common
indicator of a weakened immune system), a history of anal intercourse and
abnormal cervical cells.
“We found a number of risk factors associated with increased anal cancer risk
among HIV-positive women,” Holly said. “But the strongest is the presence of
HPV, thought to be the most common sexually transmitted agent in the world, is
the name of a group of viruses associated with genital warts and anogenital
cancer. It is estimated that 75% of the sexually active general population
between 15 and 49 years old will have a genital HPV infection at some time in
their life. According to the CDC, at any one time about 20 million people in
the U.S. have genital HPV infections that can be transmitted to others, and
every year about 5.5 million people become infected.
The new findings regarding the association between HPV and anal cancer
precursor lesions in HIV-positive women are similar to those regarding HPV and
these lesions in HIV-positive men by the same authors, and also similar to the
association between HPV and cervical cancer in both HIV-positive and
Earlier research by NCI investigators and others have shown that HPV is found
in about 99 percent of cervical cancers and 90 percent of anal cancers.
Holly and her colleagues think that women who are exposed to HPV are more
likely to get anal cancer as well as cervical cancer because they are prone to
anal and cervical cancer precursor lesions, whereas those who don’t have HPV
are less likely to get these precursor lesions.
The researchers evaluated HPV-related abnormalities in 251 HIV-positive women
and 68 HIV-negative women. They completed physical exams and obtained
questionnaire data on medical history and relevant sexual practices.
The study was funded by the National Cancer Institute, part of the National
Institutes of Health.
Collaborators on the study and co-authors on the JNCI paper are Mary L.
Ralston, MS, PhD, senior statistician, epidemiology and biostatistics; Teresa
M. Darragh, MD, associate clinical professor, pathology; Ruth M. Greenblatt,
MD, professor of medicine; and Naomi Jay, MS, RN, nurse practitioner in
stomatology, all at UCSF.