The prostate gland is situated below the bladder and in front of the rectum. It surrounds the upper part of the urethra, the tube which urine passes through to the penis.
Its main function is to secrete fluid which is part of semen which is ejaculated during the sexual act.
Prostate cancer occurs when cells in the gland grow out of control.
Prostate cancer occurs most often in men older than 50. Although prostate cancer is very common, most patients do not die from it. This is because prostate cancer usually grows very slowly.
Prostate cancer is the fifth most common cancer in both sexes combined and the second most common cancer in men worldwide. An estimated 900,000 men worldwide were diagnosed with prostate cancer in 2008, accounting for almost one in seven (14 per cent) cancers diagnosed in men.
There have been large increases in the incidence of prostate cancer in many countries worldwide, coupled with little change or small declines in mortality. Much of this increase can be attributed to the widespread use of prostate-specific antigen (PSA) testing in many Western countries. PSA testing detects both invasive cancers at an earlier stage as well as latent, non-lethal tumours that might otherwise have remained asymptomatic and undiagnosed during a man's lifetime.
The developed countries carry the biggest burden of prostate cancer, accounting for nearly three-quarters (72 per cent) of the total number of cases in 2008. Prostate cancer incidence varies more than twenty-fold across the regions of the world. Incidence rates are highest in Australia/New Zealand and Western Europe (104 and 93 per 100,000 in 2008, respectively), where prostate cancer screening and PSA testing is common, and lowest in South-Central Asia (4 per 100,000).
The risk of developing prostate cancer is high in black Caribbean and black African men and low in Asian populations, suggesting important genetic determinants of risk also exist.
Risk factors for prostate cancer
The risk factors include:
1. Age: Prostate cancer occurs more often in the elderly.
2. Genetic factors: Prostate cancer is more common in African American men and in certain genetically linked cancers such as BRCA1 or 2 mutations.
3. Dietary factors: A diet high in fat and low in vegetables is a risk factor for developing prostate cancer.
What are the symptoms of prostate cancer?
Prostate cancer often causes no symptoms at first. But if symptoms do occur, they can include:
- Needing to urinate more often than usual, especially at night.
- A urine stream that is slower than usual
- Trouble having an erection
- Blood in the urine or semen
- Severe bone pain
These symptoms can also be caused by conditions that are not prostate cancer. But if you have these symptoms, you should consult your regular doctor. Your regular doctor will check your prostate gland by putting his finger up the anus to assess for abnormal swellings in the prostate gland which is in front of the rectum.
Is there a test for prostate cancer?
Yes. Doctors use a blood test called a PSA test. This is a tumour marker blood test that is very specific for prostate cancer. However, occasionally infection in the prostate can also cause elevated results and your doctor may need to perform other tests such as:
Biopsy: Your doctor will take a small sample of tissue from the prostate. Then another doctor will look at the sample under a microscope to see if it has cancer.
Ultrasounds, MRI scan, bone scan and other imaging tests: These tests are designed to help the doctor evaluate the stage of the cancer.
How is prostate cancer treated?
Treatments options might include:
"Watch and wait," called active surveillance: Men who choose this option do not have treatment right away, but they have routine tests to check whether the cancer has started to grow more quickly. If so, they can start active treatment.
Surgery: Prostate cancer can sometimes be treated with surgery to remove the prostate gland. This can be performed using a robot. This treatment\appears to have less post-surgery complications as compared to conventional surgery.
Radiation therapy: Radiation kills cancer cells. Radiation can be given from a machine that moves around your body. Currently there are newer radiation techniques which are more focused, resulting in fewer complications on the surrounding organs such as the rectum.
Hormone therapy: Male hormones in the body make prostate cancer grow. Hormone therapy reduces the levels of these hormones, thereby shrinking the cancer. For hormone therapy, men may take medication or have surgery to remove the testicles, where male hormones are produced. This treatment is usually only for men with advanced cancer.
How do I choose which treatment to have?
You and your doctor will have to work together to choose the right treatment for you. The right treatment will depend on:
- The stage of your cancer
- Your age
- Whether you have other health problems
- How you feel about the treatment options
What happens after treatment?
After treatment, some men keep getting checked to see if the cancer comes back or starts growing more quickly. Follow-up tests include PSA tests and imaging tests.
What happens if the cancer comes back or spreads?
If the cancer comes back, you might have more radiation therapy, surgery, or hormone therapy. You might also have chemotherapy. Chemotherapy is the term doctors use to describe a group of medicines that kill cancer cells.
Can prostate cancer be prevented?
Men who are at high risk of getting prostate cancer can sometimes take a medicine to help prevent the disease. If you have a family history of prostate cancer, talk to your doctor about this option.
High intake of cruciferous vegetables such as cauliflower and broccoli has been shown to reduce the risk for advanced prostate cancer. Cohort studies have also shown tomato products to be protective.
Dr Foo Kian Fong is a Senior Consultant Medical Oncologist and Physician at Parkway Cancer Centre. He was previously a Senior Consultant in the Department of Medical Oncology at the National Cancer Centre as well as a Clinical Teacher in Medicine at the National University of Singapore.
Dr Foo obtained his Masters in Internal Medicine and Member of the Royal College of Physicians (UK) in 1997. He started training in Medical Oncology in 1998. He completed his advanced training in 2001 and was certified specialist in 2001. He had a one-year stint as a Fellow at the Peter McCallum Cancer Institute in Melbourne where he underwent training in gastrointestinal cancers from 2001 to 2002.
Dr Foo is a member of the American Society of Clinical Oncologist, European Society of Medical Oncologists and the Hong Kong College of Physicians. For more information on Dr Foo, click here.