Risk Factors for Penile Intraepithelial Neoplasia: A Population-based Register Study in Sweden, 2000-2012.

Studies on risk factors for penile intraepithelial neo-plasia have been small in size, have not distinguished penile intraepithelial neoplasia from invasive cancer, and have relied on self-reported information. This study investigated risk factors for penile intraepithelial neoplasia in a cohort of 580 penile intraepithelial neoplasia cases and 3,436 controls using information from 7 Swedish registers. Cases with penile intraepithelial neoplasia had increased odds ratios (ORs) for inflammatory skin diseases (14.7, 95% CI 6.5-33.4) including lichen planus (12.0, 95% CI 3.0-48.0), indicating lichen planus to be an important risk factor. Increased ORs were also observed for diseases of the prepuce (4.0, 95% CI 2.2-7.4), immunosuppressive drugs (5.0, 95% CI 2.5-9.8), penile surgical procedures (4.8, 95% CI 2.2-10.8), balanitis (9.2, 95% CI 5.0-16.8), genital warts (9.9, 95% CI 4.3-22.7) and organ transplantation (7.0, 95% CI 2.4-20.8). This study demonstrates important risk factors for penile intraepithelial neoplasia, providing knowledge that can help prevent the development of penile cancer.