According to the American Cancer Society, almost all prostate cancers re adenocarcinomas, that develop from the gland cells.

Other types of prostate cancer, while rare, include small cell carcinomas, neuroendocrine tumors, transitional cell carcinomas and sarcomas.

In many cases, prostate cancer grows relatively slowly, often taking years to become large enough to be detectable and even longer to spread outside the prostate. Some cases are more aggressive and need more urgent treatment.