Cancer - Prostate
The prostate is a small gland about the size of a walnut at the base of a man’s bladder in front of the rectum. It surrounds the urethra just below the bladder. The prostate secretes a fluid that contributes up to one third of the total volume of the seminal fluid released when a man ejaculates.
Prostate cancer is a condition in which some of the cells of the prostate reproduce far more rapidly than in a normal prostate, causing swelling or a tumour. If left untreated, prostate cancer cells eventually break out of the prostate and invade other parts of the body (known as metastasis).
Prostate cancer is one of the slower growing cancers and typically affects men over the age of 50, although it can affect younger men in a form that can be very aggressive. Around 20,000 new cases of prostate cancer are diagnosed in Australia each year. Approximately one in nine men will develop prostate cancer in their lifetime.
For many men, a diagnosis of prostate cancer can be frightening, not only because of the threat to their lives, but because of the threat to their sexual function. However, if prostate cancer is detected early, whilst it is still confined to the prostate gland, there is a better chance of successful treatment with minimal or short-term side effects. Successful treatment of cancer that has spread beyond the prostate gland is more difficult.
What are the causes and symptoms?
Research suggests that there is a complex interplay of factors that may have a causative role in prostate cancer. They include genetics, ethnicity, hormones, diet and the environment. We know that prostate cancer is regulated by hormones, since males who are castrated prior to puberty do not develop prostate cancer. The influence of our genes on prostate cancer development is under active investigation, both at the Garvan and around the world.
Prostate cancer often does not produce any symptoms in its early stages, which is why many cases are not detected until it has spread beyond the prostate. Most men tend to accept the onset of one or more of these symptoms as being a natural consequence of ageing:
- Waking frequently at night to urinate or a sudden need to urinate
- Difficulty in starting or stopping urinating or a slow flow of urine
- Discomfort, pain or blood when urinating or ejaculating
- Decrease in libido or reduced ability to get an erection
- What are the risk factors?
- Age - it is most common in men over the age of 50. Your risk increases with age
- Family history - men with a family history are more likely to develop the disease. Regular testing is advised from the age of 40 if you have at least one first degree relative diagnosed with prostate cancer
- Ethnicity - e.g. European men have a much higher chance of developing prostate cancer than Asian men
- High levels of testosterone (testosterone naturally stimulates the growth of the prostate)
- Diet (a high-fat diet and obesity may increase your risk of prostate cancer)
How is prostate cancer diagnosed?
As part of a regular check-up, a digital rectal examination (DRE) is recommended in order to detect any irregularities in the prostate. This may be an uncomfortable examination but is rarely painful. An enlarged gland will feel hard and possibly irregular in shape.
A Prostate Specific Antigen (PSA) test may be requested if any abnormality is found. This measures a protein in the blood which rises in concentration when there are prostate problems. In themselves, these two tests will not distinguish between cancer or a benign enlarged prostate and so, if an abnormality is found, an ultrasound scan will be carried out. A biopsy will then determine if the prostate is cancerous or benign.
What treatments are available?
Information from diagnostic tests will help determine the best treatment approach. Depending on the stage of the cancer development, a number of treatment options may be offered:
- Observation only (termed ‘active surveillance’) – monitoring the disease through regular check-ups, but delaying treatment until the disease shows signs of progressing or symptoms become troublesome
- Radical prostatectomy – an operation to remove the prostate gland and the immediate surrounding associated organs, such as the seminal vesicles
- External beam radiotherapy
- Radiotherapy using radioactive ‘seeds’ of Iodine125, which are permanently inserted into the prostate
- An operation to reduce male hormone production by removal of one or both testicles
- Medicines to suppress the production and action of the male sex hormones
What research is Garvan doing in this area?
The Garvan Institute is home to one of the largest cancer research groups in Australia. Apart from prostate cancer, we also conduct research into breast, ovarian, pancreatic, colorectal (bowel) and lung cancers.
Our prostate cancer team is aiming to identify better treatment options tailored to an individual cancer. Men with advanced prostate cancer are treated with the chemotherapy drug docataxel. Unfortunately up to 50% of men do not respond to this treatment. Our aim is to identify specific markers in the tissue or blood of these patients that will identify those that will respond to docataxel, preventing unnecessary treatment for those that will not respond.
Another approach is to find a marker in the tissue or blood of patients that will determine if the cancer is benign or aggressive. This test, taken at the time of diagnosis, will guide treatment decisions, as well as reducing anxiety, unnecessary treatment and associated side effects.
We are also studying quality of life in men treated for prostate cancer. This study will ultimately help patients, clinicians and surgeons guide treatment decisions based on quality of life instead of clinical outcomes. For our studies, Garvan scientists have recruited over 10,000 patients and have access to over 3,000 tissue samples. Our cutting-edge technology enables us to investigate a large number of genes across the extensive collection of samples.
Prostate cancer cells can spread to the skeleton but remain dormant (inactive) for many years, then start to grow and cause bone disease. At this stage the cancer is incurable. In a collaboration between bone biologists, geneticists and cancer researchers, we are seeking to identify what causes the cancer cells to suddenly grow in bone, with the goal of keeping the cancer cells in a dormant state and preventing them from becoming activated. This would have a major impact on the quality of live and survival of men with advanced prostate cancer.
Together, this knowledge will enable future prostate cancer patients to be matched up more effectively with the best possible treatments, thereby significantly improving the outcomes for patients.
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