Expectant management surveillance for patients at risk for invasive squamous cell carcinoma of the anus: a large US healthcare system experience.

Purpose: To determine the impact of expectant management surveillance for patients at risk for squamous cell carcinoma of the anus (SCCA).

Methods: Adult patients at risk for anal cancer, specifically those with human immunodeficiency virus (HIV) or known human papilloma virus (HPV) infections (anal dysplasia, anogenital warts, cervical dysplasia, or cervical cancer), underwent expectant management surveillance with targeted therapy of only grossly abnormal or symptomatic anoderm lesions. A retrospective analysis investigated the SCCA incidence in these surveilled populations and in the general population patients without known HIV or HPV infection.

Results: There were 452 incident SCCA in a population of 5,978,510 patients (mean follow-up per patient of 5.4 years). Four hundred ten cancers (90.7%) developed in 5,750,501 HIV-negative patients without documented history of HPV infection (cumulative incidence 0.007%). In at-risk patient populations, the cumulative incidence was 0.69% in patients with anal dysplasia (6 out of 872 patients), 0.14% in HIV+ patients (8 out of 5626 patients), and less than 0.1% in the remaining at-risk groups: cervical cancer (1 out of 1168 patients), cervical dysplasia (14 out of 125,604 patients), and genital warts (14 out of 94,739 patients).

Conclusions: Expectant management surveillance, with targeted treatment for symptomatic or abnormal lesions, is an effective strategy for the diagnosis of anal cancer in at-risk patient populations. In this study, most patients who developed anal cancer had no known risk factors. A screening strategy for the general population needs to be further delineated.