Prevention of recurrent high-grade anal neoplasia with quadrivalent human papillomavirus vaccination of men who have sex with men: a nonconcurrent cohort study.

BACKGROUND Most squamous cell anal cancers and precancerous lesions are attributed to human papillomavirus (HPV) infection. By preventing HPV infection, quadrivalent HPV vaccine (qHPV) reduces risk of anal cancer/precancerous lesions in young men who have sex with men (MSM) without history of anal cancer/precancerous lesions. In our practice, many persons with history of precancerous anal lesions or high-grade anal intraepithelial neoplasia (HGAIN) have been vaccinated electively. We determined whether qHPV is effective at preventing recurrence of HGAIN. METHODS This nonconcurrent cohort study evaluated 202 patients with a history of previously treated HGAIN. Eighty-eight patients were vaccinated, and 114 patients were unvaccinated. We determined the recurrence rate of histologic HGAIN in vaccinated versus unvaccinated patients. RESULTS During 340.4 person-years follow-up, 12 (13.6%) vaccinated patients and 35 (30.7%) unvaccinated patients developed recurrent HGAIN. Multivariable hazards ratio (HR) analysis showed testing positive for oncogenic HPV genotypes within 8 months before study entry was associated with increased risk of recurrent HGAIN at 2 years after study entry (HR 4.06; 95% confidence interval [CI], 1.58-10.40; P = .004), and qHPV was associated with decreased risk of recurrent HGAIN (HR .50; 95% CI, .26-.98; P = .04). Among patients infected with oncogenic HPV, qHPV was associated with decreased risk of recurrent HGAIN at 2 years after study entry (HR .47; 95% CI, .22-1.00; P = .05). CONCLUSIONS qHPV significantly reduces HGAIN recurrence among MSM and may be an effective posttreatment adjuvant form of therapy. A randomized controlled trial is needed to confirm these results.