The practice of male circumcision has many myths associated with it. Frequently, they are found to have been started by circumcised medical doctors to meet their internal emotional needs. This Knol discusses the myth that male circumcision somehow can prevent penile cancer.
Abraham Leo Wolbarst, a prominent New York physician in the early 20th century, who became a zealous promoter of universal circumcision in 1914, soon commenced to advocate circumcision to prevent penile cancer. This was at a time well before the discovery of DNA, when the causes of cancer were poorly understood, and any theory, no matter how bizarre, could be advanced.
Wolbarst soon followed up his 1926 letter with a paper, published in The Lancet in 1932, which purported to prove that circumcision provided absolute protection against penile cancer. This paper, in the profound ignorance that then existed about the etiology of cancer, was widely accepted and many medical textbooks incorporated this errant information.
Wolbarst’s claims of cancer protection are false. Girgis et al. (1973) reported penile cancer in circumcised Jewish men. Bozko & Freed (1979) surveyed the literature and reported numerous case reports of penile cancer in circumcised males. Maden et al. (1993) reported 41 cases of penile cancer in circumcised males. Rogus (1987) reported penile cancer in a man circumcised at birth. Cold et al. (1997) reported a case of cancer in a circumcised man who smoked.
Several researchers in the mid-twentieth century, perhaps misled by Wolbarst’s false assertions, theorized that smegma retained by the foreskin might be carcinogenic. Several animal studies were carried out, but not one found any association between smegma and cancer.   
Two papers published in 1970 found little reason to do a circumcision. Leitch called for personal hygiene to prevent penile cancer. Preston similarly argued, based on epidemiological evidence, that lack of personal hygiene, not lack of circumcision was the risk factor for penile cancer.
Smegma is nothing more than an amalgam of exfoliated epithelial tissue and secretions of the prostate and seminal vesicles.  There is no reason to believe that any natural product of the human body is carcinogenic.
Genuine Risk Factors
Three risk factors, human papillomavirus (HPV) infection and the use of tobacco emerged as risk factors in the 1980s. The presence of genital warts (indicative of HPV infection) is a risk factor. HPV DNA was found in human penile cancer cells,   so HPV infection is now considered to be an important risk factor. Research also implicates the use of tobacco in any form with penile cancer.  Male circumcision also appears to be a risk factor for penile cancer. Contrary to Wolbarst’s false claims, circumcision actually increases the risk of cancer, because the circumcision scar is a favored site for cancer. Bissada et al. report that cancer forms on the circumcision scar. 
Current Medical Opinion
The simple presence of the foreskin is not a risk factor for penile cancer, however lack of personal cleanliness continues to be regarded as a risk factor. Phimosis (non-retractile foreskin) in adults is an important risk factor, perhaps because it interferes with washing. The foreskin may retain carcinogens from tobacco or HPV may accumulate under a non-retractile foreskin. Circumcision is not indicated, however, because it has become outmoded, since many preferable alternative non-invasive methods to make the foreskin retractable now exist.
The American Medical Association says, because the disease is rare and occurs later in life, the use of circumcision as a preventive measure is not justified. The American Cancer Society says:
“Most experts agree that circumcision should not be recommended as a way to prevent penile cancer.”
Circumcision alters human behavior. Many males who originate in circumcising cultures, and who are likely to be circumcised, have special emotional issues. Circumcised doctors, therefore, tend to behave differently from normal doctors. Those who become doctors may use junk science to promote male circumcision. The myth of cancer protection by circumcision continues to be a favourite claim of such doctors. Abraham Wolbarst, and Abraham Ravich, who advocated amputation of the foreskin to prevent prostate cancer and cancer of the cervix, are examples of circumcised medical doctors who have advanced the prevention of cancer as an excuse to perform male circumcision in the early and mid twentieth century. Such false claims spring from the emotional needs of circumcised men.