Furthermore, at least one study has also found an association between penile cancer and heterosexual oral sex, which should give people additional motivation to use condoms for blow jobs ... particularly when they can be so much fun to put on.
Penis cancer is also associated with other sexual risk factors as well as men's health conditions, such as phimosis and balanitis. Smoking and HIV are additional risk factors. Penile cancer is rare in industrialized nations but is much more common in Africa, South America, and Asia.
Madsen BS et al. (2008) "Risk factors for squamous cell carcinoma of the penis-population-based case-control study in Denmark." Cancer Epidemiology Biomarkers and Prevention 17:2683-2691.