Breast cancer screening via mammography has long been in the front line of global efforts to reduce death from breast cancer, a disease which killed 2707 Australian women in 2005, second behind lung cancer (2716) as a cause of cancer death.
The core objective in all screening programs is to locate asymptomatic disease, preferably at an early stage, so that it can be treated by surgery, radio or chemotherapy — or often a combination of these. One problem facing all screening exercises is that “indolent” disease can be found which may have not have gone on to become life-threatening. This is a phenomenon well known in the prostate cancer debate, where a large proportion of cancer detected in screening programs is benign (many men live and die with the disease, but not because of it).
The problem is that precision with which benign cancers can be differentiated from aggressive, life threatening cancers can be poor. The result is a lot of intervention, which “wise after the event” can be concluded to have been unnecessary.
Consumers of course have every right to take that gamble when presented with information about the likelihood of a screen detected cancer being dangerous or benign. But many leading cancer epidemiologists are now calling for women to be given more complete information about the probabilities, risks and benefits.
In a multi-signatory letter published today in the UK Times, epidemiologists, breast cancer survivor advocates and other cancer experts from three continents have put it plainly, writing:
…there are harms associated with early detection of breast cancer by screening that are not widely acknowledged. For example, there is evidence to show that up to half of all cancers and their precursor lesions that are found by screening, if left to their own devices, might not do any harm to the woman during her natural lifespan.
Yet, if found at screening, they potentially label the woman as a cancer patient: she may then be subjected to the unnecessary traumas of surgery, radiotherapy and perhaps chemotherapy, as well as suffer the potential for serious social and psychological problems.
The stigma may continue to the next generation as her daughters can face higher health-insurance premiums when their mother’s overdiagnosis is misinterpreted as high risk.
We believe that women should be clearly informed of these harms in order to make their own choice about whether to attend for screening.
Breast cancer screening programs throughout the world jostle with each other to produce the best screening participation rates. Many observers feel that the provision of understandable information about the potentially serious down sides of breast cancer screening would be likely to dissuade some women from participation. So few agencies provide that information, instead providing persuasive rather than balanced information.
Women in Australia wanting to access such information and complete an on-line decision aid to assist their thinking can go here.
Decision aids are also provided for bowel cancer screening, hormone replacement therapy infant vaccination with MMR (measles, mumps, rubella).
At the end of the day the decision to test or not to test is a personal one. Being fully informed is crucial. The trouble with health in this day and age is that it has become corporatised to the degree that a system is created which not only supports testing but pushes people toward it and implies they are irresponsible if they do not do it. Ditto for vaccinations. There is never one answer to anything and while modern medicine has some remarkable skills it is also replete with failures in terms of both diagnosis and treatment in many instances. The body is a miracle. There is nothing it cannot heal. Some people may need intervention but as this story reveals, some do not. This is where personal choice comes in and where the policy of making people feel guilty if they don’t undergo tests should be recognised and stopped. The fact is in this day and age you could spend half your time being tested for one thing or another and still get hit by a bus, or something for which there is no test. The whole philosophy is based on the body being your enemy instead of your friend. Interestingly studies of Egyptian mummies showed many with tumours, cancerous and benign, which had been dealt with by the body, sometimes calcified and encased, and which has not shortened the persons life. There is a ‘fear’ mentality which drives many of these things and fear is never conducive to good decision-making. Stories like this are important reminders.
Benefits of mammography oversold? No way! My routine mammogram last July revealed microcalcification which proved to be invasive ductal carcinoma in situ. A sentinel node biopsy proved clear but had I not had that mammogram at the usual time and put it off, my prognosis would have been far less optimistic. I had no palpable lumps or other visible signs. Rather than every 2 years my surgeon recommends screening every year.
The scientific evidence from randomized trials on the impact of screening mammography in saving lives is conflicted, and the quality of the individual trials limited. The National Breast Cancer Coalition Fund (NBCCF) believes, on the basis of recently published reviews, that the benefits of screening mammography in reducing mortality are modest and there are harms associated with screening. No individual woman can be assured that screening mammography will be effective for her, and from a public health perspective, the harms and public health costs of screening mammography may outweigh the modest benefits of the intervention. Women who have symptoms of breast cancer such as a lump, pain or nipple discharge should see their family doctor. Ultimately, resources must be devoted to finding effective preventions and treatments for breast cancer and tools that detect breast cancer truly early like the new SureTouch Visual Mapping System that uses NO harmful radiation or painful compression of the breast, itself a dangerous practice. It is also able to effectively and accurately image dense breast tissue in a completely non-invasive and harmless way, something that a mammogram cannot do!! Check it out for yourselves at suretouch.com.au
Simon Chapman related screening for breast cancer to screening for prostate cancer. The latter requires more debate whilst misinformation and misunderstandings continue to lead more men (often encouraged by their well intentioned partners) to demand a PSA test from their GP. Or a GP refers a patient for a PSA test without the patient knowing about it – usually as part of other requests for pathology. What happened – especially in WA in the 90s – with the vigorous and entreprenurial promotion of PSA testing by some urologists and many of their mis-guided patients (whose lives had been ‘saved’!) was as near a medically inspired ‘epidemic’ as you might get. How many incontinent and impotent men are there in Australia who underwent interventionist treatment unnecessarily as a result of an initial PSA? No-one really knows. At least with treatment of early breast cancer there have been professional guidelines for many years and which are regularly reviewed. Prostate cancer suffered from a lack of treatment guidelines as did many of the patients through the nineties.The history of breast cancer screening in Australia demonstrates professional enthusiasm and responsibility backed by powerful consumer demands taking into account that no-one really knows what causes breast cancer or how to prevent it. Yes – there are risks associated with any mass intervention and public scrutiny is a positive step. The more transparency the better!
The article omits to mention that positive outcomes of screening tests are always followed by biopsy. It is the result from the biopsy which will determine the nature of treatment rather than the screening test. To suggest that unnecessary treatment may directly follow positive screening tests is misleading.