Testicular Cancer

Epidemiology

Testicular cancer has an annual incidence of about 8700 cases per year in the United States and accounts for only 1% of all male malignancies. Nevertheless, it is the most common carcinoma in men ages 15 to 35 years. In the United States, testicular cancer is four to five times more common in White men compared with men of other ethnicities, but incidence rates are rising in Asian/Pacific Islander and Hispanic men. Men who have cryptorchidism have a 10- to 40-fold increased risk for the development of testicular cancer in the undescended testis, but even the normally descended testis in these men has a higher risk for malignancy. Testicular cancer is associated with drinking alcohol, overweight and obesity, and elevated blood lipid levels.

Pathobiology

More than 95% of testicular tumors are germ cell cancers. Rare tumor types include lymphoma (especially in older men and often bilateral), Leydig cell, and Sertoli cell tumors. Non–germ cell tumors do not secrete serum α-fetoprotein or human chorionic gonadotropin and do not respond to platinum-based chemotherapy.

Of germ cell tumors, about half are seminomas and half are nonseminomas. Nonseminomas include embryonal cell carcinomas, yolk sac tumors, choriocarcinomas, and teratomas (with/without seminoma). Both seminomas and nonseminomas typically have amplification or aneuploidy with a gain of genetic information at the 12p position on the short arm of chromosome 12.

Clinical Manifestations

A testicular cancer may be first detected by the patient or a physician as a painless lump, often about the size of a pea. However, most patients present with unilateral pain or swelling of the testis or scrotum. Enlarging metastatic retroperitoneal nodes may cause flank pain as a presenting symptom. Less commonly, testicular cancer may be first suspected during a couple’s evaluation for infertility when the male partner is found to have oligospermia. Pulmonary symptoms of chest pain, cough, or dyspnea are seen only with extensive hematogenous spread to the lungs. Significant elevation of the serum human chorionic gonadotropin level may produce gynecomastia.

Compared with nonseminomas, seminomas occur in men one to two decades older, never secrete α-fetoprotein, have normal or modest elevation of human chorionic gonadotropin, and usually present with disease localized in the testis (stage I). Initial spread is lymphatic to ipsilateral retroperitoneal nodes, and hematogenous spread to lungs is rare.