Hormone refractory prostate cancer occurs when hormone therapy fails to the stop the growth of prostate cancer for any longer. Hormone refractory prostate cancer may occur a few months or even years after hormone therapy has been started. When patients develop hormone refractory prostate cancer, doctors may try the combined androgen blockade, or the taking the patient off an anti-androgen. Sometimes, stopping an anti-androgen and reintroducing testosterone into the blood stream will sometimes shock the tumor, which has grown used to the androgen deprivation. The tumor might then stop growing again. When hormones fail to stop the growth and spread of the cancer any longer, however, the next step is usually chemotherapy drugs. As patients advance into stage T3 and stage T4 of prostate cancer, they are more to have local extension through the lymph nodes and seminal vesicles. It is possible that the cancer could metastasize to the bones. The more quickly prostate cancer grows, the more likely the diseases will respond to chemotherapy treatment.