Incidence in United States
Penile cancer is a disease of older men, with an abrupt increase in incidence in the sixth decade of life and a peak around 80 years of age (1). In two studies, the mean age was 58 years and 55 years (2,3). The tumor is not unusual in younger men; in one large series, 22% of patients were younger than 40 years and 7% were younger than 30 years (2). The Surveillance, Epidemiology, and End Results (SEER) database reveals no racial difference in incidence of penile cancer between African American and Caucasian men in the United States (incidence for Caucasian men, 0.8 of 100,000; for African American men, 0.7 of 100,000) (3,4). In 2009 there were an estimated 1400 new cases in the United States (3).
Penile carcinoma accounts for 0.4% to 0.6% of all malignant neoplasms among men in the United States and Europe, but it may represent up to 10% of malignant neoplasms in men in some Asian, African, and South American countries (4). However, reports suggest that the incidence of penile cancer is decreasing in many countries, including Finland, the United States, India, and other Asian countries (4-7). The reasons are unclear but may be related in part to increased attention to personal hygiene.
Incidence and Significance Worldwide
Among uncircumcised tribes of Africa and within uncircumcised Asian cultures, penile cancer may amount to 10 to 20% of all male malignant neoplasms (8,9). The annual number of new cases per year worldwide is approximately 26,000 (10). Squamous cell carcinoma is the most common histologic subtype, accounting for over 95% of cases (Table 35-1) (11,12).
Table 35–1. Histopathology Subtypes of Penile Cancer |Favorite Table|Download (.pdf)
Table 35–1. Histopathology Subtypes of Penile Cancer
|Squamous cell carcinoma|
The incidence of carcinoma of the penis varies according to circumcision practice, hygienic standard, phimosis, number of sexual partners, human papilloma virus (HPV) infection, exposure to tobacco products, and other factors (13-15). Neonatal circumcision has been well established as a prophylactic measure that removes most of the risk of penile carcinoma because it eliminates the closed preputial environment where penile carcinoma most commonly develops.
The chronic irritative effects of smegma, a byproduct of bacterial action on desquamated cells that are within the preputial sac, have been proposed as an etiologic agent in penile cancer. Poor hygiene can lead to buildup of smegma beneath the preputial foreskin, with resulting inflammation. Healing by fibrosis leads to phimosis of the preputial skin, which tends to perpetuate the cycle. Phimosis is found in 25 to 75% of ...