Incidence of Anal Cancer in People with HIV Continues to Rise despite HAART

By Liz Highleyman

Several recent studies have found that rates of non-AIDS-defining cancers have risen since the advent of HAART, including a recent large analysis of nearly 48,000 participants in the Adult and Adolescent Spectrum of Disease Project and the HIV Outpatient Study.

In that study, anal cancer was 59 times more common among HIV positive compared with HIV negative individuals. Although not currently classified as an AIDS-defining cancer, anal cancer is caused by the same high-risk human papillomavirus (HPV) strains as invasive cervical cancer, which is considered AIDS-defining.

As reported in the June 19, 2008 issue of AIDS, Christophe Piketty and colleagues conducted a study to assess the changing incidence of and risk factors for anal cancer among French patients over more than a decade.

The investigators examined the incidence rates of anal cancer between 1992 and 2004 and the associated risk factors among 86,322 HIV-infected patients included in the French Hospital Database on HIV.

Results

• A total of 132 cases of anal cancer were identified.

• 124 of these cases (94%) occurred in men, of whom 75% were men who have sex with men.

• The median age at diagnosis was 42.8 years (interquartile range 36.9-49.4 years).

• At the time of diagnosis, 103 patients (78%) were receiving combination antiretroviral therapy, for a median of 37.1 months (interquartile range 4.5-59.8 months).

• The median duration of survival after anal cancer diagnosis was 5 years.

• The overall incidence rates of anal cancer rose during the study period, especially after the advent of HAART:

• 1992 through March 1996: 11 per 100,000 person-years;

• April 1996 through 1998: 18 per 100,000 person-years;

• 1999 through 2004: 40 per 100,000 person-years.

• The risk of anal cancer was dramatically higher among men who have sex with men.

• After adjusting for gender, age at inclusion in the study, HIV transmission group, nadir (lowest-ever) CD4 cell count, and AIDS status, the incidence of anal cancer was higher during the 1999-2004 period than during 1992-March 1996 (hazard ratio 2.5).

Based on these findings, the study authors concluded, "The incidence of anal cancer has increased among HIV-infected patients in France since 1996."

"Although an ascertainment bias cannot be excluded, data indicate that combination antiretroviral therapy does not prevent anal cancer in these patients," they continued. "This supports the urgent need for developing anal cancer screening programs for HIV-infected men who have sex with men."

7/15/08

Reference
C Piketty, H Selinger-Leneman, S Grabar, and others. Marked increase in the incidence of invasive anal cancer among HIV-infected patients despite treatment with combination antiretroviral therapy. AIDS 22(10): 1203-1211. June 19, 2008.