Matt Hancock's prostate cancer pickle shows why genetic testing for the healthy must be approached with caution

When he announced in January that the NHS will offer a paid genetic sequencing service for healthy people in England, Health Secretary Matt Hancock must have known he was venturing into controversial territory. Only a couple of months later, Mr Hancock himself has unwittingly exposed the very real drawbacks and challenges that this presents.


This week he has come under fire from experts for a speech given to the Royal Society, in which he discussed his own genetic test results, which revealed a 15% risk of developing prostate cancer by the age of 75. As I intend to explore these issues in some detail in this piece, I want to be clear from the outset that I do not know anything about the findings of Hancock’s tests or the basis for any information given. He said of his test: "Tragically, so many men don't find out they have it [the risk], until it's too late. The truth is, this test may have saved my life."

It’s perfectly understandable that, given this news, Mr Hancock booked to see his GP to discuss next steps. It does sound rather worrying. But as experts highlight, it is a moderate, and indeed not an abnormally high risk for a man. The prostate is simply a gland that is rather prone to cancer and about 1 in 8 men will develop it – similarly, roughly 1 in 8 women will develop breast cancer. Numbers make scary headlines, particularly when they relate to our own mortality. But a brief comparison of genetic factors relating to breast and prostate cancers reveal how complicated the risk calculations really are and the challenges future patients will face in deciding, as they gaze over the numbers they’ve paid for, what on earth do I do next?

In both cases, it’s only a small percentage of cancers that are inherited. Cancer Research UK says that about 10% of breast cancers are the result of faulty genes – BRCA1 and BRCA2 mutations being the most common. These same blighters are implicated in prostate cancer. Cancer Research also says that BRCA2 may increase the risk of prostate cancer up to 5 times, but the situation with BRCA1 is less certain. That said, BRCA 1 and 2 are found in only 0.44% and 1.2% of prostate cancer cases, respectively (Prostate Cancer UK). So, the significance of these genes in the overall picture is very unclear. In contrast, 70% of women with gene mutations linked to breast cancer will have developed the disease by the age of 80, says Cancer Research. That is plainly a much stronger association. It makes it highly likely that a woman with a mutation linked to breast cancer, will come from a family where at least one relative will have had the condition, clearly indicating that genetic testing may be advisable. Indeed, the NHS already offers genetic testing where risks of any kind of inherited conditions are known (the paid service will be a predictive one for everyone else).

Next, we need to consider not only the risk of development, but the implications in order to decide what preventative steps are advised and proportionate. Women with an increased risk of breast cancer should of course be screened regularly. It may be an agonising decision, but given the risks it is potentially worth undergoing preventative surgery – Angelina Jolie famously underwent a double mastectomy in 2013. Whilst breast cancer survival rates are high and treatment constantly improving, most BRCA1 breast cancers are of an uncommon type called Triple Negative – it’s more aggressive, is more likely to affect younger women and comes with fewer treatment options. It’s also less clearly linked to other causes of breast cancer that are associated with hormone changes and lifestyle factors. Crucially, it’s a family history that suggests the need for testing.

Bottom line: any invasive breast cancer needs treatment. The situation is not the same with prostate cancers. Age is one of the most significant risk factors. Many men will already be elderly when the condition is diagnosed. The cancers themselves vary widely but are often very slow and may never progress to a point where they are harmful during the man’s lifetime. So, if we take an overweight, black, old man with a BRCA2 mutation, we know his risk will be quite a bit higher than the average. Yet his high risk of developing prostate cancer doesn’t mean that he’s necessarily at an equally high risk of being adversely affected. From screening through to diagnosing and treatment, it’s an altogether trickier problem. IT’s more likely that genetics play a part in the overall risk of prostate cancer, rather than existing as a major risk factor in isolation (BRCA2 might be a partial exception to this). But given that screening isn’t reliable, and decisions about when to treat aren’t easy, there’s nothing to suggest that any preventative measure will be helpful. Much like your ethnicity and age, knowing whether your genes go in your favour or slightly against you doesn’t really change anything or give you any further control over the situation. Mr Hancock says he will be vigilant about his health, and good for him. But all he has now is a somewhat meaningless calculation that tells him he has a risk of prostate cancer, as do any of us with a prostate. One has to ask whether calculations that merely attest to the timeless truth that life is uncertain offer much at all, particularly when, as is often the case, you can’t do anything about the genetic element of your risk.
Alzheimer’s disease is another case in point. There is a very rare form that starts much earlier than the more common condition, and it is entirely genetic – have the gene, and you will get the condition and any children will have a 50% risk of inheriting that gene. If you have a gene that will certainly cause early dementia, testing clearly offers the ability to deal with the emotional and practical implications in a timely manner. But in a vast majority of cases, any role genetics might play in Alzheimer’s will simply be to partially contribute to your overall risk level. Having a gene that may increase your risk slightly does not negate the importance of a healthy lifestyle and other protective factors.

Our own families give us the best indications about our health and the risks we face. Everyone has a sense of this: it’s common to hear people assert that this or that runs in the family and speculate about what that means for them. There are rare instances where genetics constitutes a major or sole cause for a health problem, and professional advice is needed. My own story is another case in point – I am blind due to a rare genetic condition. It occurs through an autosomal recessive inheritance pattern, and it’s only by understanding in plain English what that means that we know why the risk was 1 in 4 for any children my parents had, but it remains no more likely to happen again to anyone else in the family – including my own biological children.
These are the exceptions, not the rule. Where testing is recommended, it needs to be done with context given to the results, not to mention support beforehand, through genetics counselling. I feel a deep discomfort about writing in such a cautionary manner about this subject. I believe that knowledge is always better than ignorance, and what is more uniquely your own and yours to decide over than your DNA – the very building blocks that make you who you are? That’s before we even start on the vast potential of large amounts of Genetic data for research – it’s great that results will have to be shared as part of the future service.
Yet islands of knowledge in a sea of ignorance leave many of us vulnerable to unnecessary anxiety and potential red herrings. It would have added little to the burden of Mr Hancock’s GP to assure him over his results. Health anxiety didn’t start with genetic testing. Yet whilst experts criticise Mr Hancock’s assertions about the value of his test, they probably understand very well that there is nothing like the seductive tinge of authority and false concreteness that figures and probabilities have to offer. They also realise that he would have to have a sound understanding both of genetics and the nature of prostate cancer itself to accurately interpret not only his risk of developing cancer, but how that relates to the risk to his health.
Should the floodgates open and the same GP have to have 100 similar conversations, that’s altogether different. I am a fierce critic of the NHS, and no fan of general practice. But we do not have a system that has the capacity for tea and sympathy. Genomics (genetics research) isn’t going away, and a good thing too. Nor is genetic testing – again, as an illness as common as breast cancer proves, nor should it. But it isn’t a crystal ball, and if we are going to charge people for its dubious predictive value, we have to create a service that doesn’t push the fallout back to our GPs. That means the often-hypothetical conversations about the future, and the psychological impact of living with calculated uncertainty. Matt Hancock’s prostate cancer pickle shows why genetic testing for the healthy must be approached with caution.