The reality is more ambiguous. Circumcised men get penile cancer at about the same tiny rate as intact men. When men of the same ages were compared, the correlation vanished. It would be erroneous to conclude from this that circumcision tends to cause penile cancer. Other factors, such as different prevalence of smoking in the two countries, may account for the difference.
Circumcision is the removal of a part or all of the foreskin at birth or later on in life.
This practice has been suggested as conferring some protection against cancer of the penis by contributing to improved hygiene. However, the penile cancer risk is low in some uncircumcised populations, and the practice of circumcision is strongly associated with socio-ethnic factors which in turn are associated with lessened risk. The consensus among studies that have taken these other factors into account is that circumcision is not of value in preventing cancer of the penis. Oily secretions from the skin and dead skin cells can also accumulate under the foreskin. The result is a thick, sometimes odorous substance called smegma.