Primary scrotal cancer: disease characteristics and increasing incidence

Scrotal malignancies are rare; the published data come from small, single-institution series, with the largest comprising only 28 patients. Using a population-based cancer registry, we describe the demographic and pathologic characteristics of scrotal cancer and report the incidence trends over time.

The Surveillance, Epidemiology, and End Results cancer registry was used to identify incident cases of scrotal cancer from 1973 to 2002. The demographic and pathologic characteristics were recorded. The incidence rates were determined and age adjusted to the 2000 United States standard population. Multivariate Cox regression analysis was performed to determine the predictors of mortality.

A total of 471 patients were identified with primary scrotal cancer. The most common histologic types were squamous cell carcinoma (32%), extramammary Paget's disease (21%), basal cell carcinoma (18%), and sarcoma (18%). A squamous cell histologic type was more common in black men than in white men (69% vs 31%, P < .001). On multivariate analysis, nonsquamous histologic types were associated with a lower mortality risk than were squamous cell carcinoma (hazard ratio range 0.43-0.63). Black race (hazard ratio = 2.02, 95% confidence interval 1.20-3.40) was associated with a greater risk of mortality. The age-adjusted incidence rate of scrotal cancer increased from 5 cases per 10 million persons in 1973 to 10 cases per 10 million persons in 2002, with an annual percentage change of 3.18 (P < .05).

Although rare, the incidence of scrotal cancer has doubled during the past 30 years and we observed significant differences in histology between races. Survival was worse in patients with squamous histologic features. Additional epidemiologic study is needed to determine the factors associated with these trends.