If a testi is found to have cancer, can chemo or radiation be used?

Depends on type: It really depends on the type of cancer. Some respond to one but not the other, some are treated with both and some don't respond to either.

It depends: Surgery is the first step in the process. The tissue type (seminoma or not) will help define the role for radiation and /or chemotherapy. The stage of disease detemined by scans and blood work will help decide the need for further therapy.