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Though the most common cancer among men in Singapore, many remain unaware of its risks, warning signs, and treatment options. Dr Wong Siew Wei shares what every man should know.

WHAT CAUSES PROSTATE CANCER?

The prostate gland is located below the bladder near the base of the penis. It produces fluid that mixes with sperm to form semen. Prostate cancer occurs when changes in the DNA of normal prostate cells trigger uncontrolled growth of abnormal cells.

ARE THERE ANY SPECIFIC FACTORS THAT MAKE IT MORE COMMON IN SINGAPORE?

Prostate cancer is the most common cancer among Singaporean men, accounting for 17 in 100 cancer cases. The high incidence is partly explained by longer life expectancy and improved cancer screening. The estimated risk in Singaporean men by age 75 is 4.8%.

IS THERE A RISE IN PROSTATE CANCER AMONG YOUNGER MEN?

More than 60% of prostate cancer occur in men aged 65 and above, with a median diagnosis age of 67. Analysis by the National Cancer Institute based in USA showed 2% relative increase per year in the incidence of prostate cancer in men aged 15-40.

This phenomenon is only partially explained by prostate specific antigen (PSA) testing and inherited genetic mutation. Prostate cancer in younger men tends to be more aggressive, often diagnosed at more advanced stages with worse prognosis.

WHO IS MORE AT RISK?

• Age: Risk rises sharply after 50.
• Ethnicity: Africans have the highest risk, followed by Caucasians, then Asians.
• Family history: Men with a family history face more than double the lifetime risk, especially if relatives were diagnosed young.
• Genes: Mutations such as BRCA1/2 or Lynch Syndrome increase risk.

Some studies suggest high dairy intake may be a risk factor but the evidence is inconclusive. Vitamins, supplements, or medications have not been proven to lower risk while sexually transmitted infections, prostatitis, or vasectomy are not proven risk factors.

HOW CAN YOUNGER MEN LOWER THEIR RISK?

The true incidence of prostate cancer in younger men remains very low, especially in Asian societies. Healthy lifestyle choices lower the risk of both cancer and cardiovascular disease.

• Stay physically active
• Maintain a healthy weight
• Eat a fibre-rich diet, low in processed foods.

WHAT ARE SOME OF THE SYMPTOMS TO LOOK OUT FOR?

Early prostate cancer usually causes no symptoms. Urinary symptoms such as frequency, urgency, or difficulty starting urination are more often due to a concomitant benign prostate enlargement. Blood in urine is rare while bone pain may signal cancer spread.

HAS THE PROGNOSIS FOR PROSTATE CANCER IMPROVED?

Yes. Survival rate has improved significantly. In Singapore, the five-year age-standardised relative survival rate has doubled to 89% over the past 50 years. Prognosis depends on the stage at diagnosis. More than 99% of patients with localised disease survive at least five years versus 37% of patients with distant spread of cancer. Unfortunately, around three in 10 cases in Singapore are diagnosed at stage 4, leading to less favourable prognosis.

WHAT ARE THE TREATMENT OPTIONS FOR EARLY PROSTATE CANCER?

For localised prostate cancer:

• Active surveillance: For small, low-risk cancers. Treatment only begins if disease progresses.
• Surgery: Radical prostatectomy is performed to remove the prostate.
• Radiotherapy:
  • External beam radiotherapy (EBRT) delivers high-energy rays.
  • Brachytherapy implants radioactive material into the prostate. It may be combined with EBRT for higher-risk disease.
• Hormonal therapy: Male hormones (androgens) promote prostate cancer cell growth. Suppression of androgens may be used together with surgery or radiation in high-risk patients.

WHAT ARE THE TREATMENT OPTIONS IF THE CANCER HAS METASTASIZED?

For metastatic prostate cancer, Androgen Deprivation Therapy (ADT), which involves surgical castration or medical castration, forms the cornerstone of treatment. All men will require additional treatment combined with ADT for optimal cancer control. Examples include:

• Androgen receptor signalling (ARS) inhibitors given orally to block androgen production or receptor activity.
• Chemotherapy to target fast-growing cancer cells.
• Radiopharmaceuticals to deliver targeted radiation to bone metastases.
• Poly (ADP-ribose) polymerase (PARP) inhibitors to exploit DNA repair gene mutations to kill cancer cells.
• Prostate-specific membrane antigen (PSMA) radionuclide therapy using radioactive molecules for precise targeting.
• Immunotherapy may help selected patients with mismatch repair gene defects.
• Bone-targeting agents protect bone strength and reduce complications from metastases.

Prognosis for prostate cancer has improved over time. Living a healthy lifestyle and discussing screening options with a doctor can help men safeguard their long-term health.

¹ Singapore Cancer Society. Common Types of Cancer. https://www.singaporecancersociety.org.sg/learn-about-cancer/cancer-basics/common-types-of-cancer-in-singapore.html
²Singapore Cancer Registry Annual Report 2022
³Singapore Cancer Registry Annual Report 2022
⁴American Cancer Society. Key Statistics for Prostate Cancer. https://www.cancer.org/cancer/types/prostate-cancer/about/key-statistics.html
⁵Bleyer, Archie, et. al. 2019. Journal of the American Cancer Society. “Prostate cancer in young men: An emerging young adult and older adolescent challenge”. https://doi.org/10.1002/cncr.32498
⁶Singapore Cancer Registry Annual Report 2022
⁷Bleyer, Archie, et. al. 2019. Journal of the American Cancer Society. “Prostate cancer in young men: An emerging young adult and older adolescent challenge”. https://doi.org/10.1002/cncr.32498
⁸Singapore Cancer Society. Common Types of Cancer. https://www.singaporecancersociety.org.sg/learn-about-cancer/cancer-basics/common-types-of-cancer-in-singapore.html