Prostate cancer - What is prostate cancer and how can it be treated?
Prostate cancer general facts
Prostate cancer is a major public health concern since 36% of cancers diagnosed in men are prostate cancers, far behind is lung cancer (14%) and rectum cancer (10.4%). One man out of 8 will suffer prostate cancer before 75 years old. At the global level 700.000 prostate cancers are diagnosed every year and the trend is toward an increase of the incidence with life expectancy growing. Although very common especially in older man, prostate cancer evolves relatively slowly and it is the 3rd cause of death by cancer although it is the most common cancer.
The prostate is a male genital gland, about the size of a chestnut. It varies in size according to age. Located under the bladder and in front of the rectum (back passage), the prostate gland forms a type of sheath around the upper part of the urethra (the canal which discharges urine from the bladder).
Contrary to many generally accepted ideas, the prostate is not directly involved in sexual intercourse: it does not affect the mechanisms of libido and erection. However it is involved in the ejaculation mechanism, since it secretes most of the fluid which is used to transport and activate sperm.
What is cancer?
All body organs are composed of cells that are specialized to the type of job that they do. Our cells are dying and being replaced constantly and this process occurs by cell division.
Cancer is caused by a defect during the division of normal cells which turns them into malignant (cancerous) cells. Malignant cells grow much faster than healthy ones and can spread into surrounding tissue.
Eventually these growing malignant cells will form a mass of tissue known as a tumor. First located in one organ, a tumor may then spread to surrounding ones. When tumor cells are transported through the blood and lymph systems to reach remote organs, we use the term metastases (from the Greek word meaning displacement).
Prostate cancer is the most common cancer in men; responsible for one in three of all male cancers. There are more cases of prostate cancer every year than lung and colon cancer.
The aggressiveness of prostate cancer can vary; some cancers develop very slowly and have no symptoms, whereas others spread quickly, invading surrounding tissue and forming metastases. The risk of prostate cancer increases with age.
Prostate cancer is diagnosed in about 8% of men. There are generally no signs or symptoms during the early stages of the disease, and these appear depending on where the cancer is located in the prostate and whether it has spread.
Assessment & diagnosis
If diagnosed early the chance of recovery from prostate cancer is very high.
Prostate cancer can be detected in routine investigations. A doctor will perform a digital rectal examination of the prostate to feel for any abnormalities such as hardness or increased size. A doctor will also carry out a blood test to record levels of prostate specific antigen (PSA). PSA is a protein produced by both normal and cancerous prostate cells and high levels of PSA can be a sign of cancer. The PSA test identifies tumors that cannot be detected by digital rectal examination (about 30% of cases of all prostate cancers). Some cancers are detected during tests for benign prostate hypertrophy.
An urologist may carry out further tests for confirm a prostate cancer diagnosis:
- Prostate biopsy: a sample of prostate tissue is removed with a fine needle for examination.
- MRI or CT scan: imaging of all body organs to detect for possible cancer in the lymph nodes, liver or other organs.
- Bone scan: imaging of all bones to check for any cancer in the bones.
Cancers are diagnosed at different stages and are classified into:
Localized prostate cancer (stages T1 or T2):
the tumor is confined to the prostate (intracapsular)
Locally advanced prostate cancer (stages T3 and T4):
the tumor spreads into surrounding organs
Treatment for localized prostate cancer
Treatments for prostate cancer include:
Surgery (radical prostatectomy)
The whole prostate is removed with the seminal vesicles (which produce semen), the connected canals (which carry the sperm), part of the neck of the bladder and the surrounding lymph nodes. Surgery requires a general anesthesia and lasts about three to four hours.
- External radiotherapy (radiation therapy or EBRT)
This treatment involves the use of radiation (very high energy rays) directed at the prostate gland to kill cancerous cells. Healthy cells have a special repair mechanism if affected by this type of radiation but cancer cells do not so are killed. Radiotherapy does not require anesthesia and treatment is generally given during regular visits over several weeks.
This treatment involves the implantation of tiny radioactive seeds directly into the prostate gland to irradiate and destroy the cancer cells.
Guided by ultrasound, the prostate gland is frozen solid killing the cancerous cells. The procedure is done under anesthesia and requires at least an overnight stay in hospital.
- High Intensity Focused Ultrasound
High Intensity Focused Ultrasound (HIFU) is a minimally-invasive treatment for localized (contained) prostate cancer. Ultrasound waves are focused with extreme precision instantly and effectively destroying the targeted cancerous cells in the prostate. The ultrasound waves are delivered via a probe which is inserted into the rectum (back passage). The treatment lasts one to three hours and can be performed under general or spinal anesthesia.