Clinical trials and placebos

Doctors have come to realize that some patients can feel better, just because they believe (mistakenly) that they are being treated. This is called the placebo effect.

Apesar deste efeito ser breve, e não ter qualquer resultado no tratamento do cancro, levava à percepção errada de que um novo tratamento estaria a funcionar.

Placebo is a substance or treatment with no active therapeutic effect used as comparison for the drug/treatment to be tested.

Despite being a temporary feeling, and with no effect on cancer, this can give the erroneous impression that a treatment is working when, in reality, is not. 

To overcome the problem, clinical trials are usually designed so patients do not know what treatment they are receiving – the real one that is being tested or one with no therapeutic effect

In the specific case of cancer trials, the comparison is done between the standard treatment used for that cancer, and the new one to be tested, which should be as effective or better than the standard one.

It would be unethical to offer a no-treatment to a patient with cancer

In very particular cases, however, a placebo – a non-active substance – can be used.

For example, when doctors are trying to understand if a new drug added to conventional treatments could improve their efficacy.

In these cases, the patient receives:

  • The standard treatment + placebo 
  • The standard treatment + new therapy

In exceptional circumstances, when there is no treatment available for the disease, the placebo might be given alone but only WITH THE PATIENT’S CONSENT.

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