Anal Cancer Rates Increase Dramatically in the HAART Era

By Liz Highleyman

Past research has shown that rates of anal cell abnormalities and anal cancer, caused by certain strains of the human papillomavirus (HPV), have not declined despite the introduction of highly active antiretroviral therapy (HAART).

New data presented at the XVI International AIDS Conference, held last week in Toronto, show that the incidence of anal cancer has increased dramatically among HIV positive people in France.

Christophe Piketty and colleagues collected data from the medical records of 81,752 subjects in the French Database on HIV. They looked at anal cases diagnosed between 1992 and 2003, broken down into three periods:

Pre-HAART: January 1992 through March 1996 (as HAART was becoming widely available in France);

Early HAART: April 1996 through 1998;

Recent HAART: January 1999 through December 2003.

Results

During the follow-up period, there were 97 confirmed new cases of anal cancer:
- 9.3% in women;
- 23.7% in men who reported no sexual contact with men;
- 67.0% in men who have sex with men.

Among the patients with anal cancer:
- the median age was 42 years;
- the median CD4 cell count at diagnosis was 265 cells/mm3;
- the median nadir (lowest ever) CD4 count was 80 cells/mm3;
- 42.3% had prior AIDS-defining conditions;
- 25.8% had never used HAART before anal cancer diagnosis.

By time period, the numbers of anal cancer diagnoses were:
- 10 cases in the pre-HAART period (10 per 100,000 persons years [PY]);
- 13 cases in the early HAART period (13 per 100,000 PY);
- 74 cases in the recent HAART period (37 per 100,000 PY).

The anal cancer incidence rate was nearly 4 times higher in the recent HAART era compared with the pre-HAART period.

Among men who have sex with men, the incidence rate also nearly quadrupled from the pre-HAART to the recent HAART period, from about 18 cases per 100,000 PY to about 62 per 100,000 PY.

By multivariate analysis, anal cancer incidence was independently associated with:
- Gender/sexual risk category (P < 0.001);
- AIDS diagnosis (P < 0.001);
- use of HAART (P = 0.057).

21 anal cancer patients experienced metastsis.

There were 37 total deaths, 24 of which were due to anal cancer.

The 3-year survival rate was 74%.

Conclusion

Based on these results, the researchers concluded that, "HAART exhibited no favorable effect on the incidence of anal cancer." The emphasized the "urgent need" to develop anal cancer screening programs for HIV positive individuals.

Session moderator Joel Palefsky suggested that the reason for the recent rise in anal cancer rates is that HAART is now HIV positive people alive long enough to progress to anal cancer, which may take a decade or more. Palefsky and others are studying management of anal cell abnormalities and cancer in HIV positive individuals, including a therapeutic vaccine.

8/21/06

Reference
C Piketty, H Selinger-Leneman, S Grabar, and others. Dramatic increase in the incidence of anal cancer despite HAART in the French hospital database of HIV. XVI International AIDS Conference. Toronto, August 13-18, 2006. Abstract TUAB0305.