Prostate Cancer: Why is It Hard to Detect Early?

The Department of Urology at Singapore General Hospital (SGH), a member of the SingHealth group, explains why prostate cancer – the third most common cancer among Singapore men – can be difficult to detect early. (iStock photo)

Prostate cancer is a disease where malignant (cancer) cells form in the prostate tissue and is more frequently found in men above the age of 50. Those with a family history of prostate cancer are also at slightly higher risk.

Why is it hard to detect prostate cancer early?

Early prostate cancer often shows no symptoms. Symptoms of the condition usually show up during later stages of the disease as the tumour grows and narrows the urethra (urine passage) and spreads to other organs.

Furthermore, symptoms are non-specific and may be caused by benign (non-cancerous) conditions such as an enlarged prostate (also known as benign prostatic hyperplasia) and prostatitis (inflammation of the prostate).

Symptoms of prostate cancer include:

Weak or interrupted flow of urine
Frequent urination (especially at night)
Difficulty urinating
Pain or burning during urination
Blood in the urine or semen
Nagging pain in the back, hips, or pelvis
Painful ejaculation

How is prostate cancer diagnosed?

Several abnormal parameters, including clinical findings and laboratory diagnostic tests for cancer, can help to diagnose prostate cancer:

1. Abnormal digital rectal examination (DRE)

The doctor or nurse examines the prostate by inserting a lubricated, gloved finger into the rectum and feeling the prostate through the rectal wall for lumps or abnormal areas.

2. Elevated Prostate Specific Antigen (PSA) level in the blood

PSA, a substance made by the prostate, may be found in increased amounts in the blood of men who have prostate cancer. PSA levels may also be high in men who have an infection, inflammation or an enlarged non-cancerous gland.

3. Transrectal or transperineal ultrasound guided biopsy of the prostate

An ultrasound probe about the size of a finger is inserted into the rectum to check the prostate. The probe is used to bounce high-energy sound waves (ultrasound) off internal tissues and make echoes. Cells are removed by a thin needle under a local anaesthetic and viewed under a microscope by a pathologist.

4. MRI of the pelvis

This detailed scan of the pelvis helps identify the extent of cancer involvement in the prostate gland and surrounding lymph nodes. A MRI scan can be performed either before or after biopsy confirmation of cancer.

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