One in three breast cancers detected by mammogram screening may actually be harmless, a study has suggested.
You have been emailing us about this story, here are some of your thoughts.
COMMENTS FROM UK
I have experienced overdiagnosis but the alternative was to be feeling as though I was "sitting on a time bomb" at every future mammogram.
Maureen O'Donnell, St Helens, UK
My partner was diagnosed with DCIS, an early stage of breast cancer, when what appeared to be cancerous cells were found by mammogram. A biopsy was taken and then monitored in the lab. From this, the doctors could define how fast the cancerous cells, if any, were growing and how dangerous the cancer was. In my wife's case, the cancer cells were confirmed, and their growth rate was high - a high grade cancer. Treatment was mastectomy. The point I'm making is this; cancer cells were confirmed in the lab after biopsy. The screening was correct, but had it been wrong the only over treatment would have been the biopsy which, although uncomfortable, was and is worth risking to catch cancer early. Because it was caught early, my wife did not need chemotherapy, and has a much better chance of staying free of breast cancer - because of screening.
Tom, London, UK
Breast cancer deaths have fallen below 12,000 for the first time
My breast cancer was found at routine mammogram after being dismissed as a pulled muscle by my GP. My consultant was emphatic that it wasn't cancer but it would be removed anyway to see what it was. It was invasive cancer and the treatment that followed saved my life. I have no doubt I would rather suffer overtreatment rather than risk premature death.
As a retired General Practitioner with 40 years experience and having been diagnosed with breast cancer as a result of a routine mammogram, I totally agree with Dr Sara Cant. Always remember - in medicine there is never a never!
My wife was diagnosed via mammogram two years ago with primary and secondary breast cancer. The only symptom she had was stinging prior to diagnosis. Neither she, her GP nor her consultant could feel any of the three lumps. After extensive invasive treatment, she has been stable these two years but now has a brain tumour. During that time policy has changed and mammograms are now offered from age 47, not 50 - this would have saved her. Don't gamble, take the test. Early diagnosis is the best chance you have.
Mark Pengilley, Carmarthen, UK
If you look at actual statistics you will find a tiny proportion of breast cancers are found by mammogram compared to physical checks for example, about one third of cancers will never have caused problems. Also having your delicate breast squeezed very hard between two plates and then blasted with x-ray can and will cause some cancers. It's a difficult choice and up to the individual but most NHS staff are not up to date with their information so make sure you are.
Zoe, Wiltshire, UK
My wife found a tiny lump (12.6mm) but it was the most aggressive form and had spread to the lymph glands even at such a tiny size. Had she not found it, she would have been faced with potentially fatal circumstances. Surely it would be better to have overdiagnosis than to ignore the scans. Unfortunately as a result of this breaking news some people will ignore the chance of a mammogram now. Not your fault, but surely they should have thought about this before they published their findings. PS - my wife had a lumpectomy, chemotherapy and now leads a perfectly normal life five years on.
Giles Parker, Altrincham, UK
Having been diagnosed with and treated for breast cancer recently, I would agree with Dr Cant's comments. Despite the gruelling treatment, I feel it is worth it in terms of peace of mind and future quality of life.
Susie, Chelmsford, UK
It is important to realise that this research comes from one of the most respected units, only dealing with the highest quality research. It would seem that screening will prevent some deaths from cancer but sadly only at the price of quite a large number of women having major breast surgery who may not have needed it. It is not that screening is a bad idea, merely that the outcomes of screening are not benign , but good and bad. As an individual you need to inform yourselves as much as you can before you are screened.
Tom Bell, Devon, UK
I went for a screening on the Cancer Big Bus as I was not due for an NHS screening for another five years. Due to that screening, rogue cells were discovered and subsequently removed - thankfully everything is ok but I would rather have known than it be discovered too late.
Diane, Belfast, Northern Ireland
Publishing 'research' such as this is dangerous and irresponsible. My Mum died from breast cancer in February and from personal experience I would rather have 'unnecessary' surgery than risk going through what my Mum went through. The cancer spread throughout her whole body and made the last few months of her life a living hell. Cancer is cancer at the end of the day and could lead ultimately to an early death, and research like this could lead to complacency in some women. Until diagnosis capabilities are far more advanced than they are now, information such as this should not be circulated to the public.
Bernadette Stone, Birmingham, UK
As a woman in the risk area of over 55 and taking HRT, I was incensed to hear the female doctor 'paternalistically' saying that research shows that 'women do not want to be told....' in relation to this evidence. I hope no such research on 'what women want to be told' is going on. If it is, it makes a mockery of the appointment I have every six months with my (female) doctor. She basically throws the decision as to whether to continue taking HRT onto me as long as she is sure I have all the information. (Though I should say she has never mentioned this subject - she just asks me if I feel well informed). I do feel capable of taking this decision, but only if the medical profession do not start backing into their bad old ways of only telling us 'what it is good for us to know'.
Deirdre MacDonald, Fareham, UK
COMMENTS FROM REST OF WORLD
A mammogram is used to detect breast lesions
I agree there is overdiagnosis. A friend was rushed to hospital to have her breast removed within four days of discovering a tumour. She was devastated. Doctors continually test for cancer, with negative results. She never had cancer in the first place. This happens to too many women in Spain. Her life was ruined, and for her husband and her daughters who now fear the same. She's lucky to have a good friend who tells her she hasn't got cancer, even before the doctors test yet again. Doctors can do wonderful things, but should not search and search until they convince themselves that someone is ill.
It was debateable after my mammogram whether to watch or have a biopsy. A second opinion told me to have a biopsy, I agreed to that and guess what? It was cancerous. And that was 15 years ago. The USA has the best of health care because as a patient I am allowed to make choices. In Britain the choice is entirely made on cost and statistics. The icing on the cake is always good. By the way I am a Brit living in the USA and I feel sure I would be a cancer death statistic if subjected to the socialised health care in Britain. Personally speaking, they are extremely antiquated in their overall health care.
Sonia Soltz, Avondale, USA
I really don't understand the aim of the researchers, knowing how breast cancer has devastated many families. In my own opinion "erring on the side of caution" is not too steep a price.
Joe the doctor, Nigeria
It is important to emphasize that the controversy is about screening for all women. I suspect that the value of screening of women with risk factors for breast cancer - a family history of breast cancer, for example - is not controversial. And report header: third of breast cancer 'harmless' is misleading and could induce a false sense of security in those with a bad family history. And I doubt if Dr Sarah Cant's statement that "Unfortunately, it is currently not possible to predict which cancers found through screening will develop aggressively and which will grow very slowly," is in context. Cancers tend to behave true to pattern within families.
Dr Max, Cape Town, South Africa