What? Screening tool for anal HSIL, thought to be pre-cursor to anal cancer.

Who? DEFINITELY: HIV-positive or negative men who have sex with men (MSMs).  HIV-positive women.  POSSIBLY: Women with high-grade cervical dysplasia, cervical cancer, or condylomata as well as in renal allograft recipients.

Where? In the primary care setting based on a thorough sexual history.

How? Insert a tap water moistened Dacron swab 1.5 inches into the anal canal and twist slowly as you remove it.  Smear onto slides or place in ThinPrep vial and prepare as you would for a cervical pap smear.  If the result is positive for atypical cells (ASCUS, LSIL, or HSIL) refer to a clinician trained to perform high-resolution anoscopy and biopsy.  If the biopsy is positive for HSIL, the patient should go to a surgeon for surgical, laser, or chemoablation of the HSIL lesion.  Anal pap should be repeated in six months with appropriate referral for a positive result.

When? Once a year for HIV positive patients and once every 3-5 years for HIV negative men at risk.

Why? There appears to be an increased risk of anal cancer in the populations mentioned above.  Though not definitively proven, atypical cells suggestive of HPV-induced change in the anal canal are thought to be pre-cancerous lesions.

Tell me more. . .
Sensitivity of two consecutive paps or more in HIV-positive MSMs=81%
Specificity=59-81%, PPV=46%, NPV=84%

Sensitivity of two consecutive paps or more in HIV-negative MSMs=50%
Specificity=90%, PPV=56%, NPV=95%

No published data for women