The overdiagnosis of breast cancer leading to unnecessary treatment

https://www.theguardian.com/society/2022/jun/09/overdiagnosis-some-breast-cancer-treatments-may-have-been-unnecessary-study-suggests

Breast cancer is one of the most common causes of death in the UK, and it may at first seem like greater screening could only be a positive thing. This article illustrates some of the issues with this myth of screening. Breast cancer screening is commonly done through a mammogram, essentially a localised X-ray of the breast tissue, this allows the detection of tumours which cannot be felt (‘palpated’). Detection of a tumour will normally lead to a biopsy, and this may lead a woman to undergo a mastectomy (mast=breast, ectomy=removal), a difficult and invasive procedure. Inevitably, as for any surgical procedure, some of these will go wrong, and some women will suffer complications as a result. This could be justified if the removal of a tumour would prevent breast cancer - however, the majority of these tumours will never become cancerous, they are benign (gentle) and will likely stay like that for the majority of the patient’s lifetime. It is because of this that any screening program must be trialled, ideally with two identical populations, with one receiving the screening and another not. Through this (and clever statistical testing) you can determine whether the screening will reduce mortality more than it will increase it. Mammogramography is a little murky, with evidence both in favour and against but is recommended for some groups of people.

Not all screening programs pass this - some private companies advocate for regular (even yearly) full body CT scans, but overwhelmingly these lead to unnecessary surgical procedures and do not serve to decrease mortality on a population level. Companies will advertise using individual anecdotes about people having tumours removed before they became a problem, but the majority of these would never cause a problem - furthermore, the radiation from a CT increases your risk of future cancer! We call tumours discovered in a scan for another condition ‘incidentalomas’ (incidental = found by accident, oma=tumour) and while some may become dangerous the vast majority never will, deciding when to operate is a complex decision which will be unique to each patient and should be discussed by their doctors. Hopefully, you can now understand why sometimes it is better to leave a tumour in!