What is prostate cancer?
This article was last reviewed and updated on August 15, 2018.
by Jason Wasserman, MD PhD FRCPC
The prostate is a small organ that is found only in males. The prostate is normally the size and shape of a walnut. It is located at the bottom of the bladder and sits between the pubic bone (i.e the front part of the hip) and the rectum. The prostate also wraps around the urethra. The urethra is the tube that conducts urine from the bladder and semen from the ejaculatory ducts to the exterior of the body. The prostate acts to secrete a fluid that helps nourish and transport sperm that come from the testicles. This fluid is made in by a complex network of small structures called glands and is then transported out of the prostate through channels called ducts.
Cancer is a word used to describe a disease made up of abnormal cells that have the ability to increase in number faster than normal cells, damage or destroy surrounding normal tissue, and travel (metastasize) to other parts of the body. Most prostate cancers grow as a large group of cells called a tumour. Pathologists call a tumour in the prostate made up of cancer cells a malignant tumour or a malignancy. Another word for a tumour is neoplasia.
Prostate cancer is a general term that is used to describe any type of cancer that starts from cells normally found in the prostate. However, there are several different types of prostate cancer and the prognosis and treatment will depend on the specific type of prostate cancer seen by your pathologist.
The most common type of prostate cancer is called adenocarcinoma. This type of tumour accounts for approximately 95% of all prostate cancers and it is the most common cancer in men over the age of 50 years.
Other less common types of prostate cancer include squamous cell carcinoma, neuroendocrine carcinoma, urothelial carcinoma, and sarcoma.
Most prostate cancers are first diagnosed after a procedure called a biopsy is performed to remove multiple small samples of tissue from different parts of the prostate. The pieces of tissue are then sent to a pathologist who examines them under the microscope. If cancer is seen in any of the pieces of tissue, your pathologist will determine the type of cancer and the amount of cancer present (the percentage of each piece of tissue that is made up of tumour cells). Your pathologist will also determine the tumour grade, which in the prostate, is given a special name -the Gleason grade. The Gleason grade is used to determine the Gleason score which is very important because your doctors will use this information to decide what type of treatment is best for you.
Your pathology report after surgery
After your initial diagnosis, you may be offered surgery, radiation therapy, medical therapy (either chemotherapy or hormone therapy), or a type of careful follow-up called active surveillance. If you have surgery to remove your prostate, the entire tumour will be sent to a pathologist for examination. In this examination, your pathologist will determine the size of the tumour and look to see if the tumour cells have spread to any tissues outside of the prostate. Your pathologist will also closely examine the cut edges of the tissue (the margins) to make sure that no tumour cells were left inside your body. If you received treatment (either chemotherapy or radiation therapy) prior to your surgery, your pathologist will also determine how well the treatment worked by looking at how much of the tumour is still alive (viable). Finally, your pathologist will carefully examine any lymph nodes removed at the same time as the tumour to see if any of them contain cancer cells (lymph node metastases). All of these details will be in your final pathology report.