Even though expert opinion recommends annual digital ano-rectal exams (DARE) for detection of anal cancer tumors among men having sex with men (MSM), the procedure is severely underutilized by clinicians and it is not known how to increase utilization. This is problematic in the context of an extremely high incidence of anal cancer among MSM, no proven treatment for anal precancerous lesions, and lack of screening infrastructure for detecting precancerous lesions, even in high-resource countries. The long-term goal of this study is to decrease morbidity and mortality from anal cancer by increasing detection of anal canal tumors through self- or partner-palpation of the anal canal. Our preliminary data indicate these exams are feasible and highly acceptable among MSM. In a diverse sample of 200 MSM, 93% of men correctly classified their self-anal exam (SAE) or partner anal exam (PAE) as either normal or abnormal, and 94% said the exams were acceptable. Given these findings, our overall objective is to determine the viability of the SAE and PAE by assessing exam accuracy and consistency of results in two clinic sites. Accuracy will be defined as concordance between clinician DARE and participant exam. The central hypothesis is that both SAE and PAE at visit 1 will have ?70% sensitivity and ?90% specificity using the clinician DARE as the gold standard at each of two visits. We will test the hypothesis with three specific aims: 1) Estimate SAE and PAE sensitivity and specificity; 2) Determine independent factors associated with SAE and PAE concordance; and 3) Determine the impact of SAE, PAE, and DARE on survival and quality of life, and evaluate the cost-effectiveness of these strategies among HIV+ and HIV- MSM.
The aims will be accomplished with a study in Houston and Chicago with a sample of 100 MSM couples (i.e., 200 partners) and 600 single MSM (two-thirds HIV-positive), aged 25-80 years, who will perform a clinician-taught SAE or PAE. The individual's SAE and partner's PAE will then be compared with the clinician's DARE. The assessment will be done at each of two visits, spaced 12-months apart, to assess retention of exam accuracy. The expected outcomes for aims 1 and 2 are sensitivity, specificity and identification of clinical and behavioral factors associated with accuracy.
Aim 3 outcomes will be the computation of incremental cost-effectiveness ratios and net monetary benefits to assess the economic viability of SAE, PAE, and DARE. This study is significant because it will demonstrate that a population with substantial rates of anal disease can recognize when disease is present. The current application will provide pivotal data that may challenge the status quo assumption that anal palpation must be performed by a clinician. The proposed research also adds to ongoing research focused on detection of anal precancers given the lack of proven efficacy for treatment of precancerous lesions, the lack of screening infrastructure for detecting precancerous lesions, the potential for self-exams in low-resource settings, and the need to address stigma-related barriers that will delay clinic attendance for ano-genital examinations among men.
This study is relevant to public health because it will assess a screening intervention that may detect early anal cancer tumors when they are much more treatable. Our pilot study indicated it was feasible to teach men having sex with men to palpate their own, or their partner's anal canal, for disease. Data in the proposed study could propel the development of a low-resource screening for rapid dissemination to populations with high anal cancer incidence and no currently proven screening options.
