Prostate cancer

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What is prostate cancer?

Prostate cancer starts in the cells of the prostate. A cancerous (malignant) tumour is a group of cancer cells that can grow into and destroy nearby tissue. It can also spread (metastasize) to other parts of the body. Prostate cancer is the most common cancer in Canadian men. Many older men have this disease without knowing it. It usually grows slowly and can often be completely removed or successfully managed when it is diagnosed. Older men with prostate cancer often die of other causes.

The prostate is part of a man’s reproductive and urinary systems. It is a walnut-sized gland just below the bladder and in front of the rectum. It surrounds part of the urethra, which is the tube that carries urine and semen through the penis. The prostate makes mucus and prostatic fluid, which mix with sperm and other fluids to make semen.

Cells in the prostate sometimes change and no longer grow or behave normally. These changes may lead to non-cancerous (benign) conditions such as prostatitis and benign prostatic hyperplasia (BPH).

Changes to prostate cells can also cause precancerous conditions. This means that the abnormal cells are not yet cancer, but there is a chance they will become cancer if they aren’t treated. Precancerous conditions that can develop in the prostate are prostatic intraepithelial neoplasia (PIN), atypical small acinar proliferation (ASAP) and proliferative inflammatory atrophy (PIA).

But in some cases, changes to prostate cells can cause prostate cancer. Most often, prostate cancer starts in gland cells of the prostate. This type of cancer is called adenocarcinoma of the prostate.

Rare types of prostate cancer can also develop. These include urothelial carcinoma (also called transitional cell carcinoma), sarcoma and small cell carcinoma.

Diagram of the male reproductive system

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