The accuracy of anal self- and companion exams among sexual minority men and transgender women: The Prevent Anal Cancer Palpation Study

Abstract

AbstractBackgroundSquamous cell carcinoma of the anus (SCCA) annual incidence among sexual minority men (SMM) with and without HIV is 85/100,000 and 19/100,000 persons, respectively, which is significantly higher than the overall incidence (2/100,000). Since SCCA tumours average ≥30 mm at diagnosis, we assessed the accuracy of individuals to self-detect anal abnormalities.MethodsThe study enrolled 714 SMM and transgender women (SMM/TW), aged 25 to 81 years, in Chicago, Illinois and Houston, Texas during 2020-2022. Individuals were taught the anal self- and companion examinations (ASE/ACE). Then, a clinician performed a digital anal rectal examination (DARE) before participants conducted the ASE or ACE. Accuracy was measured along with factors associated with ASE/ACE and DARE concordance.FindingsThe median age was 40 years (interquartile range, 32-54), 36.8% were living with HIV, and 47.0%, 23.4%, and 23.0% were non-Hispanic white, non-Hispanic Black, and Hispanic. Clinicians detected 245 individuals with abnormalities (median diameter 3 mm). Sensitivity and specificity of the ASE/ACE was 59.6% (95%CI 53.5-65.7%) and 80.2% (95%CI 76.6-83.8%), respectively. Overall concordance was 0.73 (95% CI 0.70-0.76) between ASE/ACE and DARE and increased with increasing anal canal lesion size (p=0.02). However, concordance was lower for participants aged ≥55 years (compared to 25-34 years) and when the ASE/ACE trainer was a lay person rather than a clinician.InterpretationSMM/TW who complete an ASE or ACE are likely to detect SCCA at an early stage when malignant lesions are much smaller than the current median dimension at presentation of ≥30 mm.FundingNational Cancer InstituteResearch in contextEvidence before this studyWhile squamous cell carcinoma of the anus (SCCA) incidence is substantially elevated in people with HIV, there are currently no consensus recommendations on how to screen for it, nor is there widespread technological infrastructure for one prevailing method, high-resolution anoscopy. In the absence of screening programs, the size of SCCA tumours at diagnosis are > 30 mm. We searched PubMed for articles between January 1, 2000 and June 15, 2023 using the search terms ‘anus neoplasm’ and ‘self-examination’. We found no studies assessing the accuracy of self-examinations to detect anal masses other than our prior feasibility study.Added value of this studyThe primary goal of the Prevent Anal Cancer Palpation Study was to assess the accuracy of lay self-examinations and companion examinations to recognise abnormalities in the anal region. Clinicians conducted a digital anal rectal examination and recorded all lesions observed at the perianus or anal canal. The median size of lesions was 3 mm. Participants conducted lay examinations and these results were judged against a clinician’s examination. The sensitivity and specificity of the lay examinations, for any lesion at the anal canal or perianal region was 59.6% and 80.1%, respectively. As lesions increased in size, concordance increased between clinician’s exam and the lay exam.Implications of all the available evidenceIt is now known that high-resolution anoscopy can reduce the risk for SCCA but the infrastructure using this technology is very limited in high-resource settings and almost non-existent in low resource settings, especially where HIV prevalence is highest. The evidence suggests that self- and partner examination of the anal region is feasible and that lay persons can detect lesions that are much smaller than the prevailing size of SCCA tumours.