DS74-1 Case Study 74 ■ Testicular Cancer DISEASE SUMMARY Definition Testicular cancer represents a diverse group of cancers with variable prognoses; however, all are initiated by transformation of a normal cell to a cancerous one in the testis. Subtypes of testicular cancer depend on the cell of origin and the histologic pattern of development by the tumor. Approximately 95% of testicular cancers have their origin in primordial germ cells. These abnormal growths of germ cell tissue (i.e., tumors ) are classified as seminomas and non-seminomas . Non-germ cell tumors arise in specialized cells within the testes (e.g., Leydig, Sertoli, granulosa, or thecal cells). The approximate frequencies of the most com- mon types of testicular cancer are shown in Disease Summary Table 74.1. Prevalence The American Cancer Society (ACS) estimates that there will be 8,090 new cases of testicular cancer in the United States in 2008. This accounts for approximately 1% of all cancers in males. The lifetime probability for an American white male to develop cancer of the testis is 0.2%, four to five times greater than that for black males and twice the risk of Asian-Americans. Incidence rates are 3.7 and 0.9 cases per 100,000 persons per year for whites and blacks, respec- tively. The reasons for racial differences in the incidence of testicular cancer are unknown. The risk for testicular cancer has doubled in white American males in the past 40 years. Although testicular cancer can occur at any age, including childhood, it remains the most common type of cancer diagnosed in American males ages 15 – 34 years . Significance Although testicular cancer is among the most curable types of cancer, its frequency has doubled among white American males during the past four decades. Furthermore, some types carry a very grim prognosis, and advanced cancer of any subtype can be fatal. The ACS estimates that testicular cancer will kill 380 American males in 2008, approximately 0.07% of all cancer- related deaths in men. Denial and embarrassment in talking about the testicles contribute to testicular cancer being one of the least-mentioned cancers by patients to their primary care providers. C A S E S T U D Y TESTICULAR CANCER For the Patient Case for this case study, see the printed book. 74
DS74-2 Case Study 74 ■ Testicular Cancer Causes and Risk Factors As is true for cancer in general, the precise cause of testicular cancer is unknown. However, several risk factors have been established and include cryptorchidism (i.e., failure of the testis to descend completely from the abdominal cavity into the scrotum), genetic factors, and disorders of testicular development. The strongest association is seen in males with a history of cryptorchid testis, which increases risk 10- to 40-fold. Approximately 10% of germ cell tumors are associated with cryptorchidism; furthermore, the higher the location of the undescended testis, the greater the risk. An intra-abdominal testis carries a 5% probability for developing testicular cancer, while an inguinal canal testis carries a 1.3% risk. A significant number of tumors also occur
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