How all our massive screening efforts for breast cancer can cause the very disease they are intended to detect.
Some 25,000 cases of breast cancer are diagnosed each year in Britain and 180,000 in the US. Thirteen thousand British and a hundred thousand American women will die of the disease each year. In 1990, the UK government introduced a national breast screening programme, in which women aged between 50-64 are invited for a mammogram an x-ray of the breast supposedly to detect abnormalities every three years. Women over 65 will be screened on request.
The screening programme aims to catch more cancers earlier to improve the prognosis of those women affected. Some medics insist that younger women should also have the "right" to be routinely screened.
However, there is growing evidence that mammograms which, like any x-ray, involve zapping the patient with radiation can be positively harmful and even cause the disease they are intended to detect. A Canadian study, which has yet to be published in full, seems set to confirm the findings of earlier research (P Stomper and R Gelman, Hematol Oncol Clin N Am 1989; 3: 611-40) which clearly suggests that you are more likely to die from cancer if you undergo screening than if you don't. The Canadian study, using the National Breast Cancer Screening Trial, is examining the effect of mammography on women under 50. Data released so far suggests that women whose cancer was detected through mammograms have a shorter life expectancy than those who used self examination alone.
Such concerns are far from new. As long ago as the early 1980s, the late Dr Robert Mendelsohn, in Male Practice, How Doctors Manipulate Women (Contemporary Books, Chicago, 1982), wrote: "I have been warning for years that annual mammographic screening of women without symptoms may produce more cancer than it detects." Mendelsohn quoted Dr C Bailar III, editor in chief of the Journal of the National Cancer Institute, as making the same point in a 1975 report. "His conclusion was supported by numerous studies, which suggested that accumulated x-ray doses in excess of 100 rads over 10 to 15 years may induce cancer of the breast," said Mendelsohn. Dr Irwin Bross, of the Roswell Park Memorial Institute in Buffalo, New York, also warned a congressional subcommittee in 1978 that the quarter of a million women screened in the mass NCI-ACS [National Cancer Institute American Cancer Society] screening programme will "in 15 or 20 years become the victims of the worst doctor caused breast cancer epidemic in medical history."
Some women's genetic make up may make them particularly susceptible to developing cancer after exposure to "appallingly low" doses of radiation, whether from mammograms or other x-rays, according to Dr Michael Swift, chief of medical genetics at North Carolina University (New England Journal of Medicine, 27 December 1991). Around 1 per cent of women may be carrying the gene ataxia-telangiectasia (A-T) which makes them five to six times more likely to develop breast cancer and unusually sensitive to the ionizing radiation in x-rays, he says. Dr Swift studied 1,599 close relatives of people with the rare disease associated with the gene. He estimates that in the US, between 5,000 to 10,000 of the 180,000 breast cancer cases diagnosed each year could be prevented if A-T gene carriers were protected from exposure to radiation.
In reporting Dr Swift's findings, the US magazine Glamour (October 1991) cites one Scottish and two Swedish studies which found that 40 to 50 year old women who were regularly screened had either a higher incidence of breast cancer deaths than women given physical exams alone, or no significant reduction in mortality.
Writing in How to Survive Medical Treatment (Century, 1987), Stephen Fulder says of any kind of mass screening: "For every case of a disease that is caught early there is a case of a disease that is treated when it would have got better by itself, and a case of a healthy person treated or biopsied because the screening test gave a wrong result."
That is exactly the line taken by Johannes Schmidt of the Practice for Family Medicine and Clinical Epidemiology in Switzerland. Writing in The Lancet (28 March 1992), he says that post morten findings show that many small cancers detected by mammography would have remained dormant if left undiscovered and uninterfered with. Mass breast screening is 10 times as likely to pick up a clinically benign cancer than it is to prevent a cancer death, he says.
The detection of dormant cases is particularly significant because the conventional (and unnecessary) treatment that invariably follows can be so devastating to the patient: radiotherapy, chemotherapy, long term treatment with powerful drugs which themselves have been shown to cause other cancers. It is no coincidence that the Bristol Cancer Help Centre among others has built its reputation on developing a programme simply to help cancer diagnosed patients survive their treatment.
Although mass screening in the UK is at an early stage, the experience of other countries suggests that mammograms have a high rate of inaccuracy. In Canada, during the first four years of an eight year trial, some 70 per cent of test results were unacceptable. Only in the last two years of the trial were more than half the tests up to the required standard. (The Lancet, 13 July 1991). There is also evidence from Finland that the reasonably high level of accuracy obtained during initial screening trials may not be repeated in a national programme, in which sensitivity of mammography may be 25-50 per cent lower (JAMA, 22-29 July 1992).
Besides the pointless exposure to radiation, routine screening may make women less alert to warning signs and delay seeking advice. Daniel Kopans of Massachusetts General Hospital, who has written a published critique of the above mentioned Canadian study, says: "Women may derive a false sense of security having had a negative screen for breast cancer.(The Lancet, 17 August 1991).
"Women who participate in screening should be reminded that a negative screen does not eliminate the possibility of cancer," says Kopans. "They should bring any new changes in their breasts to their doctor's attention despite a recent negative mammogram." In other words mammograms are emphatically not an alternative to routine self examination and awareness of the breasts.
This gross level of inaccuracy may be one reason why mass screening for breast cancer by mammography hasn't made much difference to survival rates. As Switzerland's Johannes Schmidt pointed out in his letter to The Lancet: "We should not overlook the finding that breast cancer mortality has remained unchanged for decades despite huge efforts to improve early detection and local treatment." Writing in The Lancet recently (24 October 1992), Kopans and others confirm the prevailing view that the death rate from breast cancer remains unchanged.
Where a malignant cancer is present, detection by mammogram, rather than physical examination, can help spread the disease. Animal studies have shown that if a tumour is manipulated, the tumour cell spread to other parts of the body can increase by up to 80 per cent (K Smatchlo et al, Ultrasound Med Biol, 1979 5: 45-49). In a letter to The Lancet (11 July 1992), Drs D Watmough and K Quan speculate that excessive levels of force ("as much compression as the women could tolerate") used in mammograms during an earlier study in Malmo, Sweden, might explain the findings by I Andersson et al (BMJ 1988; 297: 943-48) that 29 per cent more deaths occurred in the screened group than among the controls for women under 55 in the first seven years of follow up.
Guidance issued to UK operators in 1992 recommends a mammogram force limit of 200 newtons per breast during mammography the equivalent of 20 kilo bags of sugar and some of the modern foot pedal operated machines are capable of delivering up to 300 newtons.
Given the level of force involved, it is not surprising that more than a third of women experience pain or discomfort during the process (D Rutter et al, BMJ 1992; 305 443-5).
British medical opinion continues to downplay the importance of physical examination, which has no known side effects, in favour of mammography, which has plenty. This attitude was compounded last year when outgoing chief medical officer, Sir Donald Acheson, in a series of off the cuff remarks at a press conference, condemned self examination as a waste of time. Acheson's pronouncements, which received wide publicity, were apparently based on nothing more than his own personal prejudices, and contradicted the evidence of numerous studies and the guidance being issued by his own department. Health officials moved quickly to try to repair the damage done by his remarks by talking about the need for general "breast awareness", rather than actual examination confusing everyone even more.
Others were less concerned with saving Acheson's face and more concerned about saving women's breasts. Writing to the Times soon after Acheson's comments (23 September 1991), Roger Taylor, consultant clinical oncologist at Cookridge Hospital's regional radiotherapy centre, said: "Some cancers which can be felt on clinical examination are undetected by a mammogram."
Dr Joan Austoker, an adviser to Dr Kenneth Calman Acheson's successor, told the Sunday Times (6 October 1991): "What [Acheson] did not say is that more than 90 per cent of breast tumours are found by the women themselves."
A seven year study of 33,000 women by the Pennine Breast Screening Assessment Clinic in Huddersfield, published the week after Acheson's comments and reported in the Times (20 September 1991) showed that self examination could reduce breast cancer deaths by up to one fifth.
A benign lump and nine out of ten are benign is best left alone. If, however, there is good reason for further examination, you are likely to be offered some form of biopsy.
Biopsies tend to be treated as routine and minor by doctors. For the women concerned, they are anything but and should only be undergone if strictly necessary. In a standard biopsy, a thickish needle is inserted into the breast, under local anaesthetic, to remove a small piece of tissue which will then be examined for cancerous cells.
A study of 104 women undergoing biopsy for what proved to be benign lumps found that a quarter of them had "wound related morbidity" (disease) afterwards (J Dixon and T John, The Lancet, 11 January 1992). Nine patients reported that a new breast lump had developed under the biopsy scar between one to seven years after surgery. In each case, this new lump was investigated and, again, found to be benign. Eight patients had pain in the biopsy area one to six years after the procedure.
The authors of the report conclude that greater use should be made of fine needle aspiration. In this less invasive procedure, which can be done on an outpatient basis, a fine needle with a syringe is inserted in the breast to draw out a specimen of its contents. It is not without its complications, however. The BMJ (12 October 1991) cites cases of patients suffering pneumothorax (where air enters the chest, causing the lung to collapse) after needle aspiration. So you should be alert to symptoms of chest pain and breathing difficulty after needle aspiration and seek immediate medical help.
In some instances, you may be offered an excision biopsy, where the whole lump is removed under general anaesthetic. This is obviously a more radical operation, carrying all the risks of anaesthesia and should be avoided unless absolutely necessary. If you are offered excision, ask why you cannot have one of the less radical approaches. Seek a second opinion if you're not happy with the explanation.
If you do agree to an excision biopsy, read the operation consent form you are asked to sign carefully. Make sure you are agreeing only to the biopsy and nothing more drastic. Last year, the Department of Health issued guidelines to hospitals urging them to use narrow consent forms, which give the surgeon permission only to remove the lump not the entire breast if he sees fit. However, some hospitals may still be relying on the old style forms and if yours is one of them, cross out the bits you don't wish to agree to and tell your surgeon what you've done. Even if he is cavalier about lopping off your breast, he is unlikely to be quite so sanguine about leaving himself open to a clear cut malpractice suit by going against your express wishes.
Don't be bullied or panicked. If your surgeon won't treat you on this basis, go somewhere else. Operations for breast cancer are almost never emergency operations so you should be allowed time to consider your treatment options if cancer is diagnosed or suspected. As the following chilling case study shows, supplied by Aspect, the Jeannie Campbell Breast Cancer Radiotherapy Appeal, it may be essential to get a second opinion. If you sign a wide ranging consent form you may never get the opportunity to do so before it's too late.
"I went into hospital for a biopsy. I came to in dreadful pain, unable to move my left arm. I asked what had happened and soon had the ward nurse telling me there was nothing wrong with me. I crawled to the toilets and removed just enough dressings to realise my left breast was missing and something frightful had happened to my arm, which is crippled to this day.
"Somehow I got back to my bed and started to cry. No one came to my help until two doctors stood over me. The senior one said I had cancer so badly, I had six months to live.
"I put my husband in the hands of my daughter and flew out to Australia to die with my son. I gave away all my personal effects. In Australia, it was my son who pushed me into a clinic where I was vetted from top to toe.
"I did not have breast cancer. I have never had cancer. I am not going to die of cancer. I was just a wrong diagnosis.
I came home and picked up the pieces of my life."
Fiona Bawdon is a WDDTY contributing editor. Next month, we'll report on breast cancer treatments.