Ask Our Doctor: How Is Prostate Cancer Detected and Diagnosed?

Prostate cancer is the most common cancer among men in Singapore – accounting for 18% of all male cancer diagnoses between 2019 and 2023, according to the Singapore Cancer Registry Annual Report 2023.

Yet despite its prevalence, around 30% of cases are still diagnosed at stage 4, when the cancer has already spread. The difference between those outcomes comes down largely to one thing: whether the cancer was caught early.

Urologist Dr Tan Yung Khan walks through what prostate cancer screening involves, what happens when something is found, and what treatment options are available today.

Why is prostate cancer screening so important?

Prostate cancer incidence in Singapore has risen approximately 11-fold over the last 30 years – and it is now the most common cancer in Singaporean men.

The good news is that when it is caught early, while still localised to the prostate, the 5- to 10-year survival rate is between 97% and 99%. Essentially, if you are diagnosed at this stage, you are very unlikely to die from prostate cancer anytime soon.

The picture changes dramatically once the cancer has spread. For metastatic prostate cancer – where the cancer has moved beyond the prostate – the 5-year survival rate drops to around 37%, and at 10 years, it falls further to around 18%. And these are 2025 figures, after newer drugs have already improved outcomes.

The case for catching it early is clear: screening gives an 80% chance of a localised diagnosis. Without regular screening, there is a 64% chance the cancer is only found after it has already spread.

When should men start screening for prostate cancer?

Generally, we recommend starting PSA screening from the age of 50, done yearly or every two years. Some corporate health screenings test earlier than this, which can sometimes lead to confusion – so it is worth discussing with your doctor what is appropriate for your age and situation.

If there is a family history of prostate cancer, we would suggest starting earlier, at 45.

And increasingly, we recognise that family history of other cancers e.g. breast cancer, pancreatic cancer, gastric cancer, can also signal a genetic predisposition to prostate cancer. So, if those cancers run in your family, that is also a reason to have an earlier conversation with your doctor about screening.

What is the PSA test, and what happens if my result is elevated?

PSA stands for prostate specific antigen – a protein produced by the prostate gland. The blood test is simple, but an elevated result does not automatically mean cancer. It means the risk has gone up, and further investigation is warranted.

The next step is usually a more sensitive blood test called the Prostate Health Index, or PHI, which gives us a better signal of whether cancer is likely. From there, we would typically recommend an MRI of the prostate. This allows us to look at the prostate in detail and identify any areas that appear abnormal before we consider a biopsy. The days of an elevated PSA automatically leading straight to a biopsy are largely behind us.

What is an MRI-guided biopsy, and how is it different from older methods?

When I was a trainee, an elevated PSA meant an immediate biopsy – and it was what we call a systematic biopsy: we divided the prostate into zones and took a sample from each one, essentially hoping we would hit the cancer. It was, as I sometimes describe it, a tikam tikam approach – you may or may not find what you are looking for.

Today, we use MRI to identify the specific area that looks suspicious, and then use a targeted biopsy system to precisely sample that area. This gives us a much more accurate diagnosis. We have also changed the approach to how we physically perform the biopsy. The older method – a transrectal biopsy, where a needle passes through the rectal wall – carries a real risk of serious infection. We have had patients in the past who died from biopsy-related infections.

Today, we use a transperineal approach: the biopsy is taken through the skin between the rectum and the scrotum, which can be properly cleaned and sterilised. We rarely need to give antibiotics beforehand, and the infection rate is now very low.

Is a prostate biopsy painful or risky?

In a private setting, we typically perform biopsies under light sedation – patients are comfortable throughout, and many wake up saying they slept better than they had in years.

Pain after the procedure is generally minimal; I no longer routinely prescribe even paracetamol to my patients post-biopsy. The main side effects are some blood in the urine for a couple of days, and sometimes blood in the semen, but both resolve on their own.

The risk profile of a modern transperineal biopsy is significantly better than older techniques. When performed properly, it is a safe and well-tolerated procedure.

If I'm diagnosed with prostate cancer, does that mean I need treatment straight away?

Not necessarily – and this is one of the most important things to understand about how prostate cancer management has evolved.

When we look at the biopsy results, we grade the cancer. About 50% of cancers we detect fall into what we call grade group 1 – the lowest grade. For these cancers, the chance of spreading over the next 15 years is just 2%. Not death from cancer – just spreading. That is a very low risk.

For grade group 1 cancers, particularly when they are a small focus, we often recommend active surveillance rather than immediate treatment.

The reason this matter is that in the past, over-treatment was a real problem – anyone diagnosed with prostate cancer was sent straight to surgery or radiation, leading to unnecessary side effects like urinary incontinence and erectile dysfunction.

We now know that not all cancers require the same response. Grade group 2 and 3 cancers carry higher risk and we would recommend intervention. Grades 4 and 5 are aggressive and require prompt treatment.

Speak to a prostate cancer specialist to understand more about your condition and treatment options.

What is active surveillance, and is it safe?

Active surveillance means we monitor the cancer closely rather than treating it immediately. For a low-grade, localised cancer – particularly a small grade group 1 – this is a very reasonable approach. It involves regular PSA blood tests, periodic MRI scans, and sometimes a repeat biopsy to make sure the cancer has not changed character.

It is important to understand that active surveillance is not the same as doing nothing. It is a structured, protocol-driven programme of monitoring. Patients cannot simply decide to stop attending follow-up because they feel well – prostate cancer can be multifocal, meaning it can appear in more than one part of the prostate, either simultaneously or over time. Missing a follow-up appointment could mean missing a change that requires action.

What is robotic prostatectomy, and what should patients expect?

For localised prostate cancer that requires treatment, robotic prostatectomy – surgical removal of the prostate using a robotic system – is one of the main options. The surgery involves small incisions in the abdomen, through which a camera and robotic arms are inserted. The prostate is disconnected and removed, and the bladder and urethra are rejoined. Most patients go home after one to two days and need a catheter for a short period afterwards.

Two advances in surgical technique are worth knowing about:

The first is nerve sparing – because the nerves that control erection sit immediately adjacent to the prostate, we can, in suitable cases, carefully preserve them. This significantly improves the chances of erectile recovery after surgery, and we support this with a formal erectile function recovery protocol.

The second is what we call the Retzius-sparing approach – a modified surgical technique that preserves more of the supporting structures around the bladder, which substantially reduces the risk of urinary leakage. On the day of surgery using this approach, 20% of patients already have no leakage at all, and most patients have minimal issues by three months.

What is radiation therapy for prostate cancer, and how many sessions are needed?

Radiation therapy is particularly well suited to patients who are older, or who have other health conditions that make surgery less ideal.

The latest form of radiation available is proton beam therapy, which delivers radiation with greater precision to the prostate and reduces the dose received by the surrounding rectum – a benefit because rectal side effects such as bleeding can be a complication of conventional radiation.

A course of radiation typically runs for 3 – 5 weeks. It is almost always combined with hormone injections – these block male hormones, effectively a temporary medical castration – for a minimum of 2 – 3 months before radiation begins and a further 6 months afterwards. The advantage is that there is no surgery; patients can largely continue their normal lives during treatment. Side effects can include some narrowing of the urinary tract, bladder irritation, and rectal discomfort, though most are mild. It is worth knowing that some radiation-related effects can emerge 5 – 10 years later, which is why life expectancy is a relevant consideration when choosing between surgery and radiation.

What is focal therapy, and who is it suitable for?

Focal therapy is an approach for patients whose cancer is small, visible on MRI, and not too close to critical structures. Rather than removing or irradiating the entire prostate, we target only the area where the cancer is. A needle is placed into the abnormal area and either cold (cryotherapy) or heat is applied to destroy the tumour. It is typically a day procedure or overnight stay, and recovery is generally straightforward.

The appeal of focal therapy is that the impact on erectile function is less significant than with surgery or radiation – most patients experience a temporary dip but not the more pronounced changes associated with whole-gland treatment. The tradeoff is that the recurrence rate is higher. For well-selected patients undergoing surgery or radiation, recurrence is roughly 20% or less.

With focal therapy, at least 20% of patients will experience a recurrence and may require repeat focal therapy or move on to definitive treatment. It is best understood as a treatment that may be curative for some patients, but for others will be a bridge to later intervention — particularly in older patients or those with slower-growing disease.

How do doctors choose between surgery, radiation, and focal therapy?

There is no single right answer – the decision is always a shared one between the patient and the doctor, taking into account the grade and location of the cancer, the patient's age, overall health, life expectancy, and personal priorities.

For example, a fit patient with a longer life expectancy and early-stage cancer might be best served by surgery, where the long-term recurrence data is strong and follow-up is straightforward – often just an annual PSA check. An older patient with other health conditions might be better suited to radiation. Someone with a very focal, well-defined lesion and specific concerns about side effects might be a candidate for focal therapy.

What matters most is that the decision is made with full information. The days of one-size-fits-all prostate cancer treatment are behind us – and that is a significant step forward for patients.