Overdiagnosis July 11, 2009

‘Researchers in Finland concluded in a paper just published on bmj.com that one in three breast cancers detected in a population with a public breast screening program is overdiagnosed. Some cancers are harmless and will not cause symptoms or death during a patient’s lifetime. The cancer grows so slowly that the patient dies of other causes before it produces symptoms, or the cancer remains dormant or regresses. Overdiagnosis refers to the detection of those cancers. Since it is impossible to tell apart lethal from harmless cancers, all detected are treated. As a result, overdiagnosis and overtreatment are unavoidable. Karsten Jørgensen and Peter Gøtzsche at the Nordic Cochrane Centre analyzed breast cancer trends before and after the introduction of publicly organized screening programs, in order to calculate approximately the degree of overdiagnosis. They studied five countries: UK, Canada, Australia, Sweden and Norway. For the sake of objectivity, they looked at information from seven years before and after screening had been completely implemented in each country. They included both screened and non-screened age groups. Other factors that may have affected the results were assessed, such as changes in background levels of breast cancer and any compensatory drop in rates of breast cancer among older, previously screened women. The study showed a rise in occurrence of breast cancer that was directly associated to the introduction of screening. A small proportion of this increase was compensated for by a decrease in incidence of breast cancer in previously screened women. Subsequently, they evaluated each country and the estimated level of over diagnosis: the figure  in the UK is 57 percent.’

This has been my own intuitive and lay opinion for years. I have watched friends and acquaintances being diagnosed with breast cancers almost as if they had contracted flu. It has felt more and more like an epidemic for which all sorts of phenomena have been blamed, and if anything caused more and more women to have annual breast screening.  I sometimes hear women  referring to passing their annual mammography as if it was an A level. I have also met women who have had a clear mammogram one week and then produced a lump the following one.

I have watched some of them going through the agonies of recall, and waiting for more test results and critical examinations with surgeons and discussions with oncologists. I have visited them in hospital.  Thankfully, I have also seen the majority of them recover and continue with their lives, and sometimes eventually forget their ordeal and find the confidence to believe they are well rather than in remission.

 I must emphasize that I have also witnessed mothers and daughters being diagnosed – sometimes simultaneously – with a genetic variety of breast cancer in which they have been well advised to have a double mastectomy. I have also seen other women, often tragically young, diagnosed with invasive and galloping forms of hormonal cancers which have required every treatment in the book to try and reverse their obduracy.

I have sadly known some women die from breast cancer, including one as young as my next door neighbour. Read about others, like Linda McCartney, Dina Rabinovitch, and Farrah Fawcett who video recorded her two year battle with anal cancer.

The people that I have seen die from  cancers are often the same people that I have seen receive the most advanced treatments available in the world which have tragically failed to make any difference to the fatal outcome. In other cases medical science has triumphed but I’m not convinced that anybody knows why. I can’t help wondering whether for women diagnosed  as a result of screening rather than through the presence of symptoms  there is yet enough justification for invasive treatments. (Unless there is a genetic history to be considered.) At least not immediately. There is also the problem that once one manufactures a cancer diagnosis the anxiety and stress produced is also destructive. More and more, good treatment is equated with speed rather than any measured and expert period of observation. 

Like Germaine Greer, who has also written diatribes against the ever increasing screening processes that women are submitted to, I feel that we have mistakenly  elevated early diagnosis procedurals over my favoured  ’watch and wait’ process. Of course somebody very experienced needs to be doing the watching. Advanced screening techniques make it dead easy to record a tumour here or there, but  they are less schooled in recording how long the tumour may have been in situ. What scanners cannot do is provide the doctor with the critical information of what the tumour has, or is likely soon to be doing systemically. 

Not that long ago,  an elderly doctor friend of mine was invited by the Wellington Hospital to try out their latest scans to diagnose  the presence or absence of arterial plaque. At the end of the screening he was told that his arteries were lined with plaque and that he must hie himself to the Cromwell Chest Hospital for further urgent surgical interventions. Wise old owl that he is, he replied, ‘You may be able to tell me that my arteries are plaqued, but what you cannot tell me is whether it is benign plaque that stays in situ, or killer plaque that  falls off.’ He decided to wait and find out; now in his eighties he’s still doing fine.

It’s a different situation again when an undiagnosed breast cancer turns out to be due to secondaries, but by then it’s sadly too late to do much at all, except palliatively.

My own experience of abdominal illness and surgery has convinced me of the importance of learning to stay in touch with my body, know it’s general feel, so that should any new symptoms, or lumps or bumps, knock at my door I recognise their intrusion and know it’s time to do something. Fast. On the occasion when I did require abdominal surgery several years ago, retrospectively I realised that I had been aware of the symptoms for months before they were diagnosed by scanning, but that I had buried my head in the sand. I didn’t take the subtle messages from my body seriously.  I don’t go in for mammography, not since my first appointment ten years ago, when I was called back for further investigations which turned out to be a false positive. As far as I know it’s not in the family, which would make me think differently.

Recently, I heard a doctor colleague ask another, ‘When a patient arrives with what you suspect to be early symptoms of a degenerating disease do you immediately want to impose diagnostic tests and spell out the bad news, or is it better to let the illness – at least begin with –  take its course, which might with any luck be one of several years, before zooming in with a frightening and irreversible diagnosis?’ In this case they were referring to incurable and  terrifying diseases of the central nervous system.

I  fear that we have lost  faith in our bodies letting us know when something is wrong and we need to learn to prick up our ears. In the same way that so many doctors have stopped using their hands, eyes and ears, even their noses, in forming their diagnoses. I fear that too many people are losing touch, or forgetting regularly to dialogue with their  bodies. Doctors are always reminding us that ever more and more complex and expensive analyses of our blood are now the eyes of  our bodies. The doctors often omit to tell us that the credibility of many labs is contentious. Anyway, blood is another trickster and what looks like bad news one week might measure as normal three weeks later. At least it keeps the labs busy.