Burden of anal squamous cell carcinoma, squamous intraepithelial lesions and HPV16 infection in solid organ transplant recipients: A systematic review and meta-analysis.

The number of solid organ transplant recipients (SOTR), and their life expectancy, is increasing, with higher risk for long-term complications from immunosuppression. We carried out a systematic review describing the burden of anal squamous cell carcinoma (SCC), and its surrogates, in SOTR. We conducted mixed effect model-based meta-analyses evaluating incidence of anal SCC [standardised incidence ratio (SIR) versus general population, and absolute incidence rate (IR)], prevalence of anal squamous abnormalities and human papillomavirus (HPV) 16. Generalised I(2) statistics were calculated, quantifying heterogeneity. Anal SCC incidence in SOTR was elevated versus the general population (pooled SIR = 6.8, 95% CI 4.3-10.9; six studies including 241,106 SOTR; I(2) =82.3%), with an absolute IR of 12.3 (95% CI 10.4-14.7) per 100,000 person-years (five studies including 1,079,489 person-years; I(2) =0%). Prevalence of abnormal anal cytology was 12.9% (95% CI 9.2-17.7%; six studies including 328 SOTR; I(2) =17.4%). For histology, the pooled prevalence estimate of anal squamous intraepithelial lesions was 22.4% (95% CI 17.3-28.5%; three studies including 214 SOTR; I(2) =0%), with 4.7% (95% CI 2.5-8.5%; I(2) =0%) high-grade squamous intraepithelial lesions. Pooled anal HPV16 prevalence was 3.6% (95% CI 1.6-7.8%; four studies including 254 SOTR; I(2) =17.6%). There was substantial and consistent evidence of elevated anal SCC incidence in SOTR.