Cervical and anal screening

Human papillomavirus (HPV) and other sexually transmitted infections are common among women with HIV. HPV can cause abnormalities in cervical cells which may progress to dysplasia or cervical cancer if left untreated. Cervical cytology techniques such as the Papanicolaou (Pap) smear are used to screen for such cellular abnormalities before they progress to cancer.

The Pap smear involves taking a small sample of cells from the cervix. The sample is smeared onto a glass slide, stained, and examined under the microscope for abnormal or cancerous cells. A newer technique, liquid-based cytology (LBC), is now the preferred technique for cervical screening in the UK. In LBC, cells are collected as for the Pap smear, then preserved in a liquid medium before examination. LBC appears to have greater sensitivity than the Pap smear, but this has not been validated in HIV-positive women. ‘Pap smear’ is likely to remain a familiar term for cervical cytology screens regardless of the specific method used.

Abnormalities identified by cytology may warrant more thorough examination by a technique called colposcopy – an examination of the cervix using a magnifying instrument, often accompanied by a biopsy.

BHIVA recommends that women with HIV with no signs or symptoms of cervical dysplasia or cancer have cervical screening performed at diagnosis and annually thereafter, by cytology with follow-up colposcopy at initial screening and upon abnormal cytological findings.¹ US treatment guidelines recommend that, in the year a woman is diagnosed with HIV infection, she have two Pap smears and one annually thereafter as long as results are normal.²

HIV-infected men and women are also at increased risk of anal cancer and anal intraepithelial neoplasia, particularly if they engage in receptive anal intercourse. Potential screening techniques include anal cytology, as in the Pap smear technique, and high-resolution anoscopy (also called anal colposcopy), which uses magnified visual imaging. Studies have not produced consistent evidence as to which anal screening techniques might be most beneficial in detecting abnormalities that might progress to cancer. As yet, there are no guidelines or recommendations on screening for those who would be at risk. 

See also Human papillomavirus in A to Z of illnesses. 

Regular cytological screening allows for the early detection and treatment of abnormalities in the cervix, which can then be addressed before further progression to cervical dysplasia or cancer. In HIV infection, these changes may be more common, especially if there is co-infection with the human papillomavirus. There is some evidence that anal screening may be of similar benefit for people with HIV.