Testicular cancer is a type of cancer that develops in the testicles, a part of the male reproductive system. In the United States, about 8,000 to 9,000 diagnoses of testicular cancer are made each year. Over his lifetime, a mans chance of getting testicular cancer is roughly 1 in 250 (four tenths of one percent, or 0.4%). It is most common among males aged 15–40 years. Testicular cancer has one of the highest cure rates of all cancers: in excess of ninety percent; essentially one hundred percent if it has not spread. Even for the relatively few cases in which the cancer has spread widely, chemotherapy offers a cure rate of at least fifty percent.