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Why placebos for chemotherapy side effects are hard to swallow

Vomiting, nausea and diarrhoea are common chemotherapy side effects that can be so severe that patients may refuse further treatment. Emergency Brake/Flickr, CC BY-SA

It’s unthinkable to give a placebo to someone to treat their cancer, but could we use one to treat chemotherapy’s well-known side effects? Unfortunately, we may never be able to answer this question because the biggest obstacle to finding out whether it would work is emotional rather than scientific.

Let’s first consider the reason for the proposition. Recent research shows placebos are just as effective as prescribed medicines for treating emergency room patients with nausea. As nausea and vomiting are also common side effects in chemotherapy, there’s a clear scientific rationale to using them for cancer patients as well.

And there are medically valid reasons for trials to test whether this could work, especially as a way to reduce the large number of medicines cancer patients usually need. But cancer is much more emotive than other diseases and despite good reasons and intentions, we may never find the idea palatable enough to test whether it works.

The ethics of placebos

A placebo is a medicine that doesn’t contain an active drug ingredient but still has a therapeutic effect. Many studies have demonstrated a strong placebo effect. They can work even when people are told they are being given a placebo (although they work better when people are not told). But the ethics of placebo use is rather complicated.

The strange powers of the placebo effect.

Consider the ethics of these two scenarios using placebos - treating a psychosomatic disorder and testing a new drug.

For a placebo to work for a psychosomatic disorder, the patient has to be unaware they’re taking an inactive substance. In this situation, the doctor has prioritised their patient’s interest in getting better over their right to make an informed decision about whether or not to take a “medicine”.

Placebos are also used in clinical trials to help researchers identify whether a new drug works better compared to an inactive alternative. The best clinical trials use a “double-blinded” approach, where the participants know they may be given a placebo but neither they, nor the person giving them the drug, knows if they have.

There are no ethical problems with using placebos in clinical trials, assuming participants have been properly informed and given consent. But it’s not as clear-cut for psychosomatic disorders.

Even if someone’s condition is pyschosomatic, their symptoms can feel just as real and debilitating as any other ailment. In this scenario, no harm is done when the placebo works. But there could be an ethical problem if the placebo doesn’t work as anticipated.

The seriousness of cancer means it’s unethical to give cancer patients placebos because they would very likely die without effective treatment. Phil and Pam Gradwell/Flickr, CC BY

Recall that doctors don’t usually tell these patients they were given a placebo because it works better that way. So, when the placebo doesn’t alleviate the symptoms it was prescribed for, it becomes a case of missed therapy, which may result in harm or a delay in other appropriate treatment.

Chemotherapy and placebos

Generally, the seriousness of cancer means it’s unethical to treat cancer patients with placebos because they would very likely die without effective treatment. But reducing the number of drugs they have to take is desirable because it can be a burden on patients to remember to take the right medications at the right times and missed doses can have serious complications.

Most cancer patients taking chemotherapy drugs will also be given a cocktail of other drugs to treat the side effects of those medicines. These can include drugs to prevent them getting infections, such as antibiotics, chemotherapy adjuvants, drugs to boost blood production and pain killers.

Other common side effects of chemotherapy are vomiting, nausea and diarrhoea. These can be so severe that patients may refuse further chemotherapy. What’s more, after the first round of chemotherapy, some patients can experience nausea and vomiting not from the treatment itself but from previously innocuous things, such as the strong antiseptic smell of a hospital or even the sight of the building (a psychosomatic response).

It’s desirable to try to reduce the overall number of medicines a chemotherapy patient needs to take. Derek K. Miller/Flickr, CC BY-NC

Anti-emetic drugs are usually used to treat chemotherapy-induced nausea and vomiting, and patients generally respond well. But why not try to reduce the overall number of medicines a chemotherapy patient needs to take?

If the patient is fully informed and aware they could be given a placebo during treatment, especially if their nausea is psychosomatic, there would be no ethical dilemma. But placebos are most effective when the patient doesn’t know they are taking one.

Cancer is a much more emotive disease and chemotherapy is far removed from the rapid decision-making environment of the hospital emergency room, which is where the nausea-placebo study was conducted. In those situations, medical teams make decisions without consulting the patient or their family and may unilaterally decide to use a placebo for nausea.

In contrast, family and friends tend to be much more involved with cancer patients in their treatment decision making. Many may find the idea of their loved one being given a placebo unpalatable.

So what do you think? Should medical staff consider the use of placebos to treat the chemotherapy side effects of cancer patients? Would you be happy if your mother, father, sister or brother was given a placebo while undergoing chemotherapy?

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