As with last week, I’m writing this in advance and scheduling it to go out on Sunday, as I will be in London with my son for the Arsenal Premier League victory parade. I dearly hope it will be a double celebration with the Champions League too, but one trophy is enough for me.
I wrote last week of my intention to do a mini-series on disease prevention, covering the major conditions where we can take meaningful steps to reduce risk. I’ll try to keep to the same structure each week: why the condition matters, what we cannot control, what we can influence, key takeaways, and some deeper information for those who want it.
This is not about blaming people for illness. It is not about pretending we can prevent everything. It is about understanding the risks we can measure, the habits we can change, and the treatments we can use earlier and more intelligently.
I had intended to start with cardiovascular disease, but as you know I also like to keep things topical in my blogs, and prostate cancer screening was in the news this week, so I thought cancer might be a better place to start.
Why cancer matters
Cancer matters because it is common, feared, and deeply personal. Most of us will have been affected by it in some way — either ourselves, through family, friends, colleagues, or patients. It is also one of the areas of medicine where the limits of prevention are most obvious. Some people develop cancer despite apparently doing everything right. Others live with substantial risk factors and never do.
That is part of what makes cancer so difficult emotionally. It can feel random and unfair, but that does not mean prevention is irrelevant. It means we have to talk about prevention carefully, honestly, and without blame.
What we cannot control
There are some things we cannot change. We cannot change our age. We cannot rewrite the genes we were born with. We cannot always know our full family history. We cannot fully control environmental exposures we may have had earlier in life, and we cannot remove the element of chance.
Family history sounds simple, but in real life it often isn’t. In my own case, I appear to have no family history of prostate cancer. But that may simply be because the men in my family died young from other causes, I come from a small family, and previous generations were never tested. “No family history” is not always the same as “low inherited risk”.
This is one reason why prevention is not about certainty. It is about risk, and risk is often imperfectly measured.
What we can influence
With respect to cancer prevention more generally, it is important to recognise that some cancer risk is bad luck, some is genetic, some is environmental — but some is modifiable.
Some practical areas to focus on are:
Do not smoke.
Keep alcohol intake moderate.
Maintain a healthy weight.
Exercise regularly.
Protect skin from excessive UV exposure.
Use established screening programmes where applicable, including bowel, cervical and breast screening.
Consider lung cancer screening if eligible.
Take persistent or unexplained symptoms seriously.
Understand your family history where possible.
Consider genetic advice where there is a strong family pattern of cancer.
Support vaccination programmes that reduce cancer risk, such as HPV vaccination.
None of these steps guarantees protection. But they all sit within the same philosophy: doing what we reasonably can to stack the odds in our favour.
Screening: why it is more complicated than it sounds
Most people naturally think: serious disease + available test = screen everyone. But a screening programme is not the same as offering a test to someone with symptoms.
Screening means inviting apparently healthy people for testing, and that creates a much higher bar. The test has to find important disease early enough to improve outcomes, but without causing too much harm through false alarms, unnecessary investigations, overdiagnosis, or treatment of disease that may never have caused problems.
This is why the prostate cancer screening story this week is so interesting. The UK National Screening Committee, or UK NSC, recommended against a national PSA-based prostate cancer screening programme for most men, including routine screening for all men over 50. It did recommend targeted screening every two years for a narrower group: men aged 45–61 with a BRCA2 gene variant and a family history of breast, ovarian, pancreatic or prostate cancer. It did not recommend targeted screening for Black men or for men with a family history but no known BRCA2 variant, citing insufficient evidence that screening would do more good than harm in those groups.
In my opinion, it is perfectly legitimate for charities, patients, clinicians and politicians to question the evidence, ask whether the process has weighed risk correctly, and push for better research. I am not saying the decision was right or wrong, but I do find it troubling if complex screening decisions become matters of political pressure rather than independent evidence review.
Screening policy should be evidence-led, because screening healthy people can cause harm as well as benefit. The key harms in prostate cancer, as with many other cancers, are overdiagnosis, anxiety, biopsy complications, and treatment of cancers that may never have caused problems, with potential consequences such as urinary, sexual and bowel side effects.
Key takeaways
Cancer prevention is not about blame.
Screening is not automatically beneficial just because a disease is serious.
Some cancer risk is genetic, environmental or simply bad luck.
Some risk is modifiable, particularly through smoking, alcohol, weight, exercise, UV exposure, vaccination and screening where evidence supports it.
Family history is important, but “no family history” is not always the same as “low risk”.
The aim is not to control everything. The aim is to use the best evidence we have to stack the odds in our favour.
For those who want to go deeper
And what might the future hold? In my view, this is seriously interesting. As you may know, I have a background in genetics and run the Dorset services for inherited heart disease. Cancer genetics and blood-based cancer detection are moving quickly. Some cancers shed genetic material into the bloodstream, and the hope is that detecting this earlier may bring forward diagnosis and treatment.
But the same screening principles still apply. Earlier detection is only truly useful if it improves outcomes for patients without causing too much harm through false positives, anxiety, unnecessary scans, or treatment of disease that may never have caused problems. That is why this field is exciting, but also why it needs careful evidence rather than hype.
Cancer prevention is not about blame and it is not about certainty. It is about using the best evidence we have, recognising uncertainty, and doing what we reasonably can to stack the odds in our favour.
In this week’s research video, I take a closer look at the latest evidence around the Galleri multi-cancer blood test, including the recent NHS-Galleri trial results, the potential role of blood-based cancer detection in future preventive medicine, and the important cautions around false positives, overdiagnosis, anxiety and follow-up pathways.