Anal Pap screening is feasible in routine HIV care

Anal Pap screening as part of routine HIV care is acceptable and feasible, US investigators report in the May edition of AIDS Patient Care and STDs.

Abnormal anal cells were detected in 53% of patients. A low CD4 cell count was associated with abnormal cytology, but there was no relationship with anal intercourse.

“Our study is in concordance with other studies showing that anal precancerous lesions are commonly found in HIV-infected individuals,” comment the investigators.

Early detection of pre-cancerous cell changes is associated with improved treatment outcomes. Like cervical cancer, most cases of anal cancer are associated with infection with high-risk strains of human papilloma virus (HPV). Cell changes occur before genital cancers develop and these can be detected by tests. The incidence of cervical cancer fell dramatically after the introduction of routine screening.

However, even though HIV-positive individuals have an increased risk of anal cancer, few patients are routinely screened for pre-cancerous anal cell changes.

Investigators from the Department of Veteran’s Affairs in Miami, Florida, wished to see if an anal Pap screening programme would be acceptable to their patients. They also wanted to establish the prevalence and risk factors for pre-cancerous cell changes.

The study was conducted between February and July 2006. A total of 160 patients were invited to participate in the research, and 131 (82%) agreed. All were men. These patients had a median age of 49 years, 52% were black and 60% denied any history of anal intercourse.

Overall, 54% of patients had a CD4 cell count above 350 cells/mm³, 47% had an undetectable viral load and 75% were taking antiretroviral therapy.

Anal cytology was unsuccessful in 33 patients (25%), much higher than the 5% - 9% failure rate seen in other studies.

“Factors that could have been related to the elevated number of unsatisfactory results are lack of staff expertise in collecting…smears since the procedure was newly introduced into the clinic, and also the fact some patients may have had anal intercourse or anal manipulation within 24 h prior to the anal sample collection,” note the investigators.

Over half (53%) of the patients with adequate samples had abnormal anal cytology, and 37% of these individuals had low-grade pre-cancerous cell changes, with a further 5% having high-grade changes.

After controlling for potential confounders, a low CD4 cell count was the only factor significantly associated with abnormal anal cytology (p = 0.026).

A total of 33 patients with abnormal cytology had further investigations including high-resolution anoscopy and biopsy. These examinations confirmed the presence of pre-cancerous lesions in all but two of the patients. Moreover, anal cancer was detected in two individuals.

Further analysis showed that high-grade pre-cancerous cell changes were associated with a lower CD4 cell count (p = 0.03) and a higher viral load (p = 0.005).

Neither a history of anal intercourse nor the number of recent sex partners were significantly associated with pre-cancerous anal cell changes.

“In our study abnormal anal cytology was as frequent in patients who denied anal intercourse as in patients with a history of anal intercourse,” comment the authors. However, they caution that some patients may not have accurately reported their sexual behaviour because of the stigma that is attached to anal sex.

The investigators conclude that screening was “well accepted” and that their research “demonstrates the feasibility of anal Pap smear screening in routine HIV care that makes possible the early detection of precancerous and even cancerous lesions.”

They add, “HIV-infected patients need to know they are at risk of anal cancer, and anal health should be an issue of priority for HIV care providers to discuss with their HIV-positive patients.”