Do No Harm in cancer screening programmes: can consent save the day?

By Lotte Elton

Screening might harm you. That isn’t what the adverts will tell you. But, increasingly, there is a growing awareness that, for some, cancer screening might lead to unnecessary and potentially harmful investigations and treatments. This seems to violate the ethical principle of non-maleficence: the injunction that doctors ‘do no harm’ to their patients. But clearly doctors do cause harm to their patients: after all, patients may develop blood clots after surgery, or suffer gruelling nausea during chemotherapy.

However, there is a difference between having chemotherapy for cancer and being screened for cancer. It is easier to justify harm to an individual if it might bring about great benefit to them: for example, giving chemotherapy with many side effects in order to (hopefully) treat a patient’s cancer. But it is tricky to justify medically unnecessary harm to an individual in order to benefit somebody else: even if we know that the benefit of screening outweighs the harm at a population level, this is still compatible with lots of individuals receiving harmful treatment that has no benefit to them. Unfortunately, it is virtually impossible to identify these individuals: we cannot know ahead of time which individuals will benefit and which will be treated unnecessarily. Moreover, assessing who was harmed and who benefited is tricky even after screening takes place, since there is no way to tell whether or not an abnormality would have ever progressed to cancer.

On the other hand, any patient could theoretically stand to benefit from screening. And elsewhere in medical practice, there are risky interventions which we might offer to patients, even if we are not entirely sure they will benefit. In order to justify these potential harms, practitioners of medicine often turn to informed consent: in other words, the patient was offered a treatment, was counselled about the possible harms and benefits, and nonetheless decided to proceed. By giving their consent, patients justify medical interventions (for example, appendix removal surgery) which might otherwise violate important norms (for example, that we do not cut open another person).

Even so, there remains some concern that consent – including consent to screening – may still be problematic: for example, that patients may have an inadequate understanding of the harms and implications of the medical interventions to which they are consenting. Furthermore, even if we were to give patients more information, it is hard to know exactly what information to give: for example, a patient may agree to undergo surgery if they are told that there is a 90% survival rate, but refuse the same surgery when told it has a 10% mortality rate. This is deemed the ‘framing effect’, a term first coined by the psychologists Daniel Kahneman and Amos Tversky.

In writing this paper, though, this kind of framing effect was not my main concern. Instead, I wanted to probe at something deeper: the idea that therapeutic medicine (like surgery for appendicitis) and preventive medicine (like screening for cervical cancer) are paradigmatically different, and that this has implications for the validity of patient consent. To this end, I make a distinction between ‘patient requests’ and ‘doctor invitations’, which I use as shorthand to describe therapeutic medicine and preventive medicine respectively. In therapeutic medicine, a patient comes to their doctor with a concern (abdominal pain, for example) which they would like addressed. In preventive medicine, the doctor (or a medical organisation, like the NHS Cervical Cancer Screening Programme) approaches the patient with an invitation to a medical intervention.

What are the implications of making these kinds of medical invitations? In this paper, I suggest that medical invitations pose a problem for consent on two grounds. First, I argue that making medical invitations may mean that patients are liable to be misinformed, since patients often appear to think that medical invitations are made with their benefit, rather than population benefit, in mind. Second, I argue that making medical invitations may place pressure upon patients to accept, because such invitations are made from a position of authority. How can we solve these issues? To conclude the paper, I argue that the best way to make patient’s consent to medical invitations more robust is to tell them about these issues: in other words, to explain to them that when they receive an invitation to screening, they may be misinformed about its implications or pressured to accept.


Paper title: Non-maleficence and the ethics of consent to screening

Author: Lotte Elton

Affiliations:  Department of History and Philosophy of Science, University of Cambridge

Competing interests:  None to declare

Social media accounts of post author(s):  @LotteElton (twitter)

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