https://www.straitstimes.com/life/st-picks-should-you-screen-for-prostate-cancer
2025-05-06
By---Dr Wong Seng Weng is the medical director and consultant medical oncologist at The Cancer Centre.
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*Smoking and obesity are associated with increased risk of several cancers and prostate cancer is no exception.*
SINGAPORE – Picture yourself as a senior public health administrator tasked with setting up a cancer screening programme for the country.
Would you ignore the most common cancer in the population and devote resources to screening for the second most prevalent type?
Well, that is exactly what Singapore is doing for its national cancer screening programme for men. Ignoring the commonest cancer in men – that being prostate cancer – and focusing on screening for colorectal cancer, the second commonest. There is logic behind such incongruence.
Prostate cancer has, in recent years, pipped long-time chart leader colorectal cancer as the commonest cancer affecting men in Singapore, based on the statistics released from the Singapore Cancer Registry towards the end of 2023. There are about 1,500 new diagnoses of prostate cancer in Singapore every year.
Under the Healthier SG initiative, men in Singapore get free screening for colorectal cancer using a stool-testing technique (known as the faecal immunochemical test) to check for the presence of occult blood as an early sign of the presence of a malignant tumour, starting from the age of 50.
This screening test is similarly made available to women. Women are also screened for the commonest female cancer, breast cancer, through the use of regular mammography.
Screening for the commonest cancer in men, prostate cancer, on the other hand, is conspicuously missing from the national programme.
Most common, but not most fatal
Why are we ignoring this elephant in the room? It is because this elephant, while big, is less likely to trample over us.
While prostate cancer is the commonest cancer afflicting men, it is not the most fatal. In the league table ranking cancers causing death in the local male population, prostate cancer comes in at No. 5 – behind lung, colorectal, liver and pancreatic cancers. About 250 men in Singapore die of prostate cancer every year.
The big gap between the number of new diagnoses and the number of deaths is a clear indication that many prostate cancer patients do not eventually die of this disease.
While many were no doubt cured of their prostate cancer through appropriate treatment, many died with their prostate cancer and did not die of prostate cancer. That is to say, they died from other causes and their underlying prostate cancer never threatened their lives.
There are two main reasons for the relatively low mortality rate of prostate cancer – lower degree of aggressiveness of the cancer and higher age at diagnosis.
While prostate cancers present a spectrum of aggressiveness, many lie at the lower end of this scale and have relatively indolent behaviour. Prostate cancer is rare below the age of 40 to 50. Peak incidence lies between the ages of 65 and 75.
Elderly patients are more likely to also suffer from other medical conditions, such as heart diseases, and are more prone to develop other common conditions causing death, such as pneumonia. Hence, many elderly patients with indolent prostate cancers eventually succumb to other medical conditions.
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This may come as a surprise, but it is not unusual for doctors to advise prostate cancer patients to let the cancer be and not institute treatment. Doctors use a collection of data points such as the stage (how advanced the cancer is), the speed of growth (Gleason score) and the level of cancer marker in the blood (prostate specific antigen or PSA) to decide whether the cancer is likely to eventually threaten life.
If that likelihood is low, doctors will adopt a watch-and-wait approach. On the contrary, if the cancer is deemed to be potentially life-threatening, the patient may be asked to undergo surgery, radiotherapy or endocrine therapy (hormonal therapy).
Clearly, while not all men will benefit from improvement of longevity through early detection of prostate cancer, a select group may still have much to gain from regular screening through the measurement of the level of PSA in the blood.
The cancer screening guidelines from Singapore’s Ministry of Health do not specifically advocate population-wide prostate cancer screening.
The American Cancer Society, however, recommends that men above the age of 50 with more than 10 years of life expectancy should consider screening.
Those with a strong family history of prostate cancer, potentially due to harmful genetic inheritance, should start screening at a younger age. Those with a first-degree relative (father or sibling) diagnosed with prostate cancer before the age of 65 should start screening at age 45, while those with two such family members should start at age 40.
Risk factors
Men should also pay more attention to the risk factors for prostate cancer.
Not all risk factors are modifiable. Age is the most important factor, but there is no fountain of eternal youth to be found. Race, interestingly, makes a difference. In Singapore, prostate cancer is the commonest cancer in Chinese men, but the fourth commonest in Malays.
Many are aware of the elevated breast and ovary cancer risk associated with inheritance of the BRCA gene, which Hollywood actress Angelina Jolie carries. Men who inherit this gene double or triple their risk of prostate cancer.
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More important, from the cancer prevention point of view, are the modifiable factors.
Diet plays a part. A high intake of animal fat increases the risk. Of concern are reports that even omega-3 fatty acids, traditionally viewed as a “good” animal fat, are associated with increased risk of prostate cancer.
Higher fruit and vegetable intake is beneficial, in particular lycopene-rich food such as tomatoes and papayas. Increasing soya intake is helpful.
Coffee lovers will be happy to learn that coffee intake is associated with lower risk. While it is unclear which component in coffee plays a part, caffeine is probably not the beneficial stuff as decaffeinated coffee has the same protective effect.
There is no health supplement proven to lower prostate cancer risk. Instead, a few reports indicate a higher risk associated with vitamin E supplement.
Other lifestyle factors play a role. Smoking and obesity are associated with increased risk of several cancers and prostate cancer is no exception.
One question I have been asked frequently is whether a high frequency of sexual intercourse increases the risk. It does not. Research, in fact, showed that a higher frequency of ejaculation is associated with decreased risk of prostate cancer. Of course, I am not advocating this as a strategy to reduce prostate cancer risk, but it is helpful to dispel a common myth.
So, should you undergo regular PSA screening for prostate cancer?
My take is that screening for prostate cancer should be done selectively. This cancer is different and the “screening is good” or “screening is unnecessary” dichotomy does not apply.
The potential benefits of early detection reducing prostate cancer mortality must be weighed against the psychological stress of detecting an abnormal PSA, the potential side effects of treatment and the possibility that these efforts may be futile and not improve longevity.
This is a decision that you need to make with your doctor. At least, you now know that it is safe to have a few cups of coffee while you think through this.
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Dr Wong Seng Weng is the medical director and consultant medical oncologist at The Cancer Centre.
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