With the recent announcement of an international conference to raise awareness of overdiagnosis, a darker side of medicine is quickly becoming exposed.

Evidence is building to show that doctors are over-cautiously labelling perfectly healthy people ill and in need of treatment. Although we often assume that unneeded medicine can’t do us any harm, such a view is dangerously misguided. It is without doubt that rapid diagnosis can be life-saving in serious cases, but a line must be drawn. Unnecessary treatment can cause more harm than good. Doctors must act to tackle this problem or patients will continue to be exposed to the rising dangers of overdosing and overtreatment.

Usually, a doctor is accused of negligence in terms of underdiagnosis: the failure to diagnose at all or quickly enough. However, the other side of the ‘clinical negligence coin’ is becoming one of the biggest problems in modern medicine. Defence organisations may attempt to shift blame onto a ‘compensation culture’ within society, yet it is the development of modern technology within the medical world which has allowed the problem to spread.

Overdiagnosis of pulmonary embolism (PE) – a blockage in a lung artery – illustrates the problem well. In 1998, multidetector computed tomographic pulmonary angiography (CTPA) was introduced as a new technology with which to detect the condition. It is much more sensitive than its predecessor and detects blockages so small that they pose no threat to the patient’s health. Despite this lack of risk, doctors cannot resist a PE diagnosis. Whether they are haunted by the fatal consequences of severe PE, dazzled by the cutting-edge technology, influenced by commercial vested interests or merely covering their backs, hasty diagnosis cannot continue.

Despite a near doubling of diagnoses between 1998 and 2006, age adjusted mortality from PE changed little. It is clear that the definition of the illness has widened to include not only life-threatening blockages but those which do not threaten life at all. As definitions widen, thresholds fall allowing more and more patients access to treatment. Handing out diagnoses so generously achieves nothing. Clinically insignificant blockages do not affect the health of the patient, do not impact on mortality rates and, therefore, do not need to be detected or treated.

Most concerning, however, is the harm caused by overdiagnosis of PE. Doctors’ determination to ‘solve the problem’, regardless of the size of the blockage, becomes counterproductive in endangering patients’ health. Unnecessary exposure to radiation poses significant risks while warfarin, the drug used to treat the condition, can cause major bleeding. It is clear that the dangers are no less concerning than those of underdiagnosis. Another worrying effect is the waste of NHS resources. In general, £128bn is frittered away every year on unnecessary treatment. This is yet another example of patients’ health being endangered by the medical profession. While doctors spend time and money on perfectly healthy patients, they detract attention and resources away from those who truly require help.

So what can be done? Ultimately, doctors must take responsibility. They have the expertise to distinguish between cases which need treatment and those which would be better off without it. Therefore, they must use this to draw a line and adhere to it. The profession is not without recommendations of how to achieve this. As suggested by the ‘Choosing Wisely’ campaign, cutting-edge technology is not always the best. CTPA should be reserved for patients at a sufficiently high risk of PE. If this level is not met, doctors should revert back to scanning which only detects blockages large enough to be dangerous.

Where should the line be drawn? Many methods have been suggested to ascertain whether a patient is at a high enough risk of PE to benefit from CTPA testing. The Wells Score is a good example. This takes into account criteria such as heart rate and immobilisation to calculate the level of risk. Patients can rest assured that the outcome of such tests will lead them down the right road. Whether this means testing or no testing, treatment or no treatment, their health will come first.

It is important to recognise that the issue of overdiagnosis is not confined to PE. Breast cancer, thyroid cancer, prostate cancer, kidney disease and asthma are among the many areas in which patients receive inappropriate treatment. In up to 40% of overdiagnoses, ‘abnormalities’ are found incidentally when the patient is being tested for other reasons. However, in many cases, the abnormality is irrelevant as the patient suffers no symptoms and will suffer no effects. Treatment in such circumstances will result in one of two outcomes. Firstly, the doctor may make no difference to the patient’s life as it is impossible to improve the health of an already perfectly healthy individual. Secondly, they may, perhaps permanently, damage the patient’s health. Clearly then, doctors have taken their pursuit of good health too far. We are urged to question our faith in the miracles of medicine as they are quickly becoming overshadowed by its propensity to cause more harm than good.

In conclusion, the medical profession must redirect its pursuit of good health. It must stop throwing around diagnoses and narrow its focus to clinically significant cases. This would not only reduce instances of overdiagnosis but also those of underdiagnosis as it would allow doctors to direct their attention to patients in need without distraction. If they fail to implement a solution, they will not only risk patients’ health but their own reputation and public trust in the profession. We must hope that the international ‘Preventing Overdiagnosis’ conference is a success in starting the ball rolling.