Is testicular removal a cure for prostate cancer?

No. Testicular removal, or surgical castration, is not a cure for prostate cancer. It is used as a type of androgen deprivation therapy (adt) in cases where the cancer has spread, or metastasized. Adt aims to deprive the cancer of testosterone, which fuels its progression and spread. Often, adt is not surgical but accomplished through medication.
No . It is used to decrease testosterone, which is the fuel for prostate cancer. Another way of achieving this is with lh-rh analogs (i.e. Lupron), but more expensive.