Prostate cancer is the most common cancer diagnosed in men and the third most common cause of cancer death. It is more common in older men, with 85% of cases diagnosed in men over 65 years of age.
Incidence and mortality
The risk of being diagnosed with prostate cancer by age of 85 is 1 in 5 men.
Screening
Currently, there are no tests available with sufficient accuracy to screen populations of men for early signs of prostate cancer.
Symptoms and diagnosis
Urinary symptoms are nonspecific and include frequent urination, particularly at night, pain on urination, blood in the urine and a weak stream. More widespread disease often spreads to the bones and gives pain or unexplained weight loss and fatigue.
Diagnosis is made using a digital rectal examination to feel the prostate and a blood test for PSA. A rectal ultrasound can image the prostate and multiple needle biopsies are used to detect the disease and determine its aggressiveness (the Gleason grade of 1-5 is added from two samples to form a score; low scores of 2-4 indicate slow growing disease).
Staging
The staging system used for prostate cancer is the TNM system, which describes the stage of the cancer from stage I to stage IV. Ninety per cent of patients present with local disease. Bone and CT scans are used to determine spread.
Causes
The risk of prostate cancer rises with age, increasing rapidly over 50 years. Family history increases the chances of developing the disease. There has been some association with a diet high in fats and low in fresh fruit and vegetables. Men of African descent are at higher risk than men of European descent, and there is an association with high testosterone levels.
Prevention
There are no proven measures to prevent prostate cancer.
Treatment
Low-grade disease confined to the prostate may be ‘watched’ (regular surveillance by doctor) if not causing symptoms.
Surgery with curative intent removes the whole prostate (radical prostatectomy). The main side-effects are impotence and incontinence. Radical radiotherapy can also be given with curative intent, either with external radiation or by implanting radioactive seeds (brachytherapy). Side-effects are similar to surgery, however bowel problems may also occur.
For widespread disease, hormone therapy reduces the stimulus of the male hormones. Removing the testis or injecting luteinising hormone releasing hormone (LHRH), or anti-androgen hormones, can hold the disease for three to four years and may improve outcomes if given early with radiation in high risk patients. When hormone resistance occurs, chemotherapy with docetaxel can be used, or mitoxantrone can control symptoms. Bisphosphonates (e.g. zoldedronate) can be used to help control bone metastases.
Prognosis
An individual's prognosis depends on the type and stage of cancer, as well as their age and general health at the time of diagnosis. The five year survival rate for men diagnosed with prostate cancer is over 92%. Nearly all patients who present with localised disease will live beyond five years, with the 10- and 15-year survival rates being 93% and 77% respectively.