What is prostate cancer?

The prostate is a gland located below the bladder and in front of the rectum. The prostate’s job is to make some of the fluid that protects and nourishes sperm cells in semen. The prostate is the size of a walnut and may grow in size as we grow older. The stimulus behind this is the male hormones (also known as androgens) in the body, such as testosterone and dihydrotestosterone. Prostate cancer is a disease in which cancer or malignant cells form in the tissues of the prostate. In the vast majority of cases, prostate cancer starts off within the glandular cells and this is also known as adenocarcinoma.

Prostate cancer is fairly common, isn’t it?

Prostate cancer is a very important health issue. Worldwide, it is the second most common cancer in men, behind lung cancer. One in seven men will be diagnosed with prostate cancer during their lifetime. Closer to home, prostate cancer is the third most common cancer in Singaporean men, behind colorectal and lung cancer. About 3,500 Singaporean men were diagnosed with prostate cancer between 2009 and 2013.

Are there warning symptoms or signs to look out for?

Early prostate cancer often does not cause any symptoms. But more advanced prostate cancers can sometimes cause symptoms, such as:

- problems passing urine (frequent urination, especially at night; painful urination, and difficulty starting and maintaining a steady flow of urine)

- blood in the urine

- pain in the hips, spine, ribs or other areas from cancer that has spread to bones

- weakness or numbness in the legs or feet, or even loss of bladder or bowel control from cancer pressing on the spinal cord

Other conditions can also cause similar symptoms. For example, trouble passing urine is much more often caused by benign prostatic hyperplasia (BPH) than cancer. Still, it is important to tell your doctor if you have any of these problems so that the cause can be found and treated, if needed.

What are some of the screening modalities that doctors employ?

Screening tests for prostate cancer include a tumour marker blood test (for prostate-specific antigen, or PSA in short) and digital rectal examination. During a digital rectal examination, the doctor would insert a gloved lubricated finger into the rectum.

Prostate cancer on its own is a heterogeneous disease which means that it can exhibit a spectrum of behaviours, ranging from the slowest growing, most indolent type of prostate cancer that is unlikely to cause any problems for that man with that cancer for the rest of his life, to some other prostate cancers at the opposite end of the spectrum where the disease is actually far more aggressive and more likely to have spread to different parts of the body leading to its incurability.

So a big challenge for doctors screening patients for prostate cancer is to identify which patients are likely to fare better than others and therefore to spare patients from issues related to over-diagnosis and even over-treatment.

Are there preventive measures for prostate cancer?

There is no sure way of preventing prostate cancer. The reason why is that we do not know exactly what causes prostate cancer. We do however know some factors that may increase a person’s risk of getting prostate cancer. These so-called risk factors are not always modifiable, meaning we cannot control them. These include age, ethnicity, and a strong family history of prostate cancer. Some other risk factors are modifiable, including one’s diet and lifestyle. A high fat diet may increase a person’s risk of developing prostate cancer. There are therefore some things that we can do to lessen our risk of developing prostate cancer, like taking a healthy diet, exercising regularly, and maintaining a healthy weight.

When should men start screening regularly, if there are no signs and symptoms?

There are different camps for and against prostate cancer screening. According to Singapore’s Ministry of Health cancer screening guidelines, there is insufficient data to support prostate cancer screening in our local population. Instead, doctors may adopt a shared approach to decision-making for men who express an interest in prostate cancer screening.

Men who are between 50 and 75 years of age may be offered screening for prostate cancer after a discussion of both the potential benefits and risks associated with prostate cancer screening. On the other hand, men who may be at higher risk, such as African-American men and men with a strong family history of prostate cancer, may be offered screening at an earlier age.

What are the treatment options?

The management of prostate cancer can be quite varied. Depending on the situation, management of men with prostate cancer might include observation, which in medical terms is called expectant management or active surveillance.

Active forms of treatment include surgery, radiation therapy, hormonal manipulation and chemotherapy. More recently, researchers have developed vaccine therapy as well as various bone-directed therapies for patients with prostate cancer. These treatments are generally used one at a time, although in some cases we may combine them for better effect. The treatment choices for prostate cancer should take into account a person’s age, life expectancy, other medical conditions that patients may have, the stage and grade of cancer, and the patient’s feelings about the possible side effects from each treatment.

Dr Zee Ying Kiat is a specialist in medical oncology at Parkway Cancer Centre. He conducted research on novel targeted therapies for colorectal, gastric, liver and pancreatic cancer.

Parkway Cancer Centre
Tel: (+65) 6738 9333
Email: enquiry@pcc.sg
www.parkwaycancercentre.com

Material provided by Parkway Cancer Centre