A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for many cancers.
But risk factors don’t tell us everything. Having a risk factor, or even several, does not mean that you will get the disease. On the other hand, some men who develop penile cancer have no known risk factors. Even if a man does have one or more risk factors for penile cancer, it is impossible to know for sure how much that risk factor may have contributed to causing his cancer.
Scientists have found certain risk factors that make a man more likely to develop penile cancer.
Not being circumcised
Circumcision is the removal of all (or a part) of the foreskin. This procedure is most often done in infants but it can be done later in life. Circumcision seems to protect against penile cancer when it is done shortly after birth. Although men who were circumcised as babies have a lower chance of getting penile cancer than those who were not, studies looking at this issue have not found the same protective effect if the foreskin is removed later in life. The reasons for this are not entirely clear, but may be related to other known risk factors.
For example, men who are circumcised cannot develop the condition called phimosis, and cannot accumulate material known as smegma (see next section). Men with smegma or phimosis have an increased risk of penile cancer. The later a man is circumcised the more likely it is that one of these conditions will occur first. Also, circumcised men are less likely to get and stay infected with the human papilloma virus (HPV), even after accounting for differences in sexual behavior. Again, the later a circumcision is done, the more likely that a man will be infected with HPV before the procedure.
Phimosis is defined as the inability of the prepuce (foreskin) to be retracted behind the glans penis in uncircumcised males.
Nearly all males are born with congenital phimosis, a benign condition that resolves in the overwhelming majority of infants as they transition into childhood. In 1949, Douglas Gairdner showed that only 4% of infants had a fully retractable foreskin at birth but that 90% did by age 3 years. Contemporary work demonstrates that only 1% of males aged 17 years still have an unretractable foreskin. Adult phimosis (ie, pathologic or true phimosis) may be caused by poor hygiene or an underlying medical condition (eg, diabetes mellitus).
Uncomplicated pathologic phimosis is usually amenable to conservative medical treatment. Failure of medical treatment warrants surgical intervention, usually in the traditional form of a circumcision or preputioplasty.
Although phimosis is the most common indication for adult circumcision, other reported indications include paraphimosis, balanitis without phimosis, condyloma, redundant foreskin, Bowen disease, carcinoma, trauma, disease prophylaxis (eg, HIV infection), and patient choice.
In weighing the risks and benefits of circumcision, doctors consider the fact that penile cancer is very uncommon in the United States, even among uncircumcised men. Neither the American Academy of Pediatrics nor the Canadian Academy of Pediatrics recommends routine circumcision of newborns. In the end, decisions about circumcision are highly personal and depend more on social and religious factors than on medical evidence.