Breast cancer is the second biggest lady killer in the Western world, we're told. Most experts believe the causes are almost certainly to be found in the environment - particularly with the latest disclosure that most women with breast cancer have high traces of parabens in their breasts (Horm Res, 2003; 60 [Suppl 3]: 50; see box, p 2).
Some of the highest breast cancer rates are found in the US, where breast cancer strikes one in every nine women, and 40,000 Americans die of it every year. The picture in the UK is only slightly better, with one in 12 women at risk, but a staggering 33,000 new cases are diagnosed annually - twice the rate of only 40 years ago.
The bare statistics seem frightening, and have been used by doctors to press-gang women into being tested for breast cancer as early as possible. In the US, screening for breast cancer has become a huge money-making industry - a trend echoed even in Britain's cash-strapped NHS.
But what if the figures are wrong? What if medicine is seriously overdiagnosing as cancer a condition that is essentially harmless?
During the last 10 years, breast screening has been called into question largely over basic questions of accuracy.
In fact, a growing number of experts believe that the advent of breast-cancer screening has created a problem where none may actually exist, labelling and treating many conditions as cancer which aren't serious or life-threatening.
The astonishing fact is that fully half of all cases of so-called 'breast cancer' might not be cancer at all, but a harmless abnormality that will never progress to cancer. In some 16,000 cases in the UK and 40,000 cases in the US, women could be being wrongly treated for cancer.
What is breast cancer?
Breast cancer is a growth of undifferentiated cells in the breast area usually causing a lumpy tumour. However, the overwhelming majority - some 80 per cent of breast tumours - is not cancerous.
The breast is a fairly simple organ, mostly made up of fat, and lymphatic and connective tissues. Milk is produced in the nodules, and a system of ducts passes the milk to the nipple. It is in these lobules and ducts that cancer is believed to develop, eventually spreading out to the other parts of the breast and forming a tumour.
Although doctors often pretend otherwise, the various stages of breast cancer are still not well understood.
The first stage of one type of cancer is believed to be when a milk duct or lobule is invaded by microscopic calcifications. Most of these are so tiny that they cannot be seen or felt, and are only detectable on a mammogram. The calcifications are believed to be the precursors of cancer, but they are not in themselves cancerous. Nevertheless, they are somewhat misleadingly called 'carcinomas in situ' (CIS), which means 'cancers in place'. Doctors refer to the calcifications that occur in lobules as 'LCIS' and the ones in ducts as 'DCIS', which is much the more common diagnosis of the two.
Before mammography, DCIS was virtually unknown, but it now accounts for up to 50 per cent of breast cancer diagnoses. The conventional view is that identifying DCIS is a good thing as it picks up cancer in the early stages, thus enabling treatment to prevent the cancer from developing.
At least, this is the message given to patients, but some experts are beginning to question the whole philosophy.
'Doctors should make it clear that DCIS is not cancer; it is only a possible precancer,' says Dr Eric Wiener, head of breast oncology at the Dana-Farber Cancer Institute in Boston, Massachusetts.
The plain fact is that most DCIS does not become cancerous - a finding made by pathologists doing autopsies on women who had died of something else. Post mortems show that many women may have DCIS harmlessly in their breasts for years; it is only when DCIS spreads out beyond the duct (it is no longer 'in situ') that cancer might begin.
The problem is that doctors don't know what types of DCIS break out and become carcinogenic, or even how often DCIS turns into cancer.
If left untreated, some DCIS will break out and cancer will develop. But these cases are by far the minority. Most DCIS causes no problems at all.
Nevertheless, doctors almost universally recommend treatment, arguing that it is always 'better to be safe than sorry'.
Cancer statistician Dr Donald Berry, head of biostatistics at the M.D. Anderson Cancer Center in Houston, Texas, labels this 'knee-jerk' medicine.
In the hard-hitting article 'Epidemiology versus scare-mongering', UK cancer expert Professor Michael Baum attacked health professionals for scaring women into unnecessary treatment. Baum has 30 years of experience as a breast-cancer surgeon at the Royal Free Hospital and, in his view, if left untreated, as many as 80 per cent of all DCIS cases will never become cancerous (Breast J, 2000; 6: 331-4).
This is backed up by American research aimed at quantifying the true risks of DCIS. Cancer statistician Dr Virginia Ernster, at the University of California at San Francisco, looked back over the death statistics of about 7000 women who had been diagnosed with DCIS, both before and after screening had become widespread. She found that, before the advent of screening, only 3.4 per cent of the women died of breast cancer, with the figure dropping to 1.8 per cent after its introduction. In either case, the 'risk of death was low', commented Dr Ernster (Arch Intern Med, 2000; 160: 953-8).
Cut, poison and burn
The usual treatment for DCIS is a combination of the three standard anticancer weapons - surgery, chemotherapy and radiation, often disparagingly dubbed 'cut, poison and burn' by their detractors.
Although DCIS is not breast cancer, its treatment regime is similar to what is given for the full-blown disease. Doctors will either recommend surgery to remove the so-called diseased part (lumpectomy) or even to remove the whole breast (mastectomy), followed by chemotherapy and/or radiation (Am J Nurs, 2001; 101: 11).
Nevertheless, a recent review of the evidence by cancer expert Maryann Napoli came to a stark and dramatic conclusion: there is no benefit whatsoever from any conventional treatment for DCIS.
Napoli, who runs the Center for Medical Consumers in New York, surveyed the US mortality rates in women diagnosed with DCIS, and found that just 1 per cent of them died from breast cancer - whether their DCIS was treated or not (Am J Nurs, 2001; 101: 11).
'Seventy per cent of women with a DCIS diagnosis are being overtreated and getting all the downsides of treatment - surgical scars, side-effects of surgery, radiation and tamoxifen,' says Professor Susan Love, cancer expert at the University of California at Los Angeles.
For the past 20 years, the 'wonder drug' tamoxifen has been the treatment of first choice for breast cancer. Its mode of action is to attack oestrogen, the hormone that is believed to cause breast cancer. In advanced cases of breast cancer, the drug does appear to have an effect, improving some women's long-term survival by up to 25 per cent. Results like this have hit the headlines.
What is less well known is that tamoxifen is useless for around 30 per cent of women with breast cancer because they have a form of the cancer that does not respond to oestrogen (Lancet, 1998; 351: 1451-67).
Because it appeared to work in more advanced breast cancers, in the 1990s, tamoxifen began to be used for DCIS - again with initially glowing headline research results. But, as more and more symptomless, essentially healthy women were being given the drug, it soon became clear that the medicine was worse than the disease it was meant to prevent.
Reports came tumbling in that tamoxifen was causing osteoporosis, retinopathy, stroke, blood clots, and cancers of the womb, ovaries, liver and gastrointestinal tract - and some of the cases were fatal (J Gen Intern Med, 2003; 18: 937-47). The most serious side-effect has been endometrial cancer, forcing the World Health Organization to classify tamoxifen - the supposed miracle anticancer drug - as a group 1 carcinogen (cancer-causing agent).
That was in 1996, yet doctors continue to prescribe the drug for DCIS.
Six years later, in May 2002, the Food and Drug Administration (the highly conservative US government healthcare agency) finally issued an official warning against tamoxifen, pointing to the 'serious, life-threatening or fatal events' caused by the drug, and questioning its whole prescribing rationale, including for women 'at high risk of cancer' (FDA statement, 15 May 2002).
Radiotherapy for DCIS
Besides tamoxifen, 'just-in-case' DCIS treatment also includes radiotherapy, where X-rays are targeted on the cancer area - even though, of course, there is no actual cancer.
In some women, radiotherapy itself can cause cancer, in particular, a rare 'aggressive' cancer called 'angiosarcoma'; this is almost always fatal (J Am Acad Dermatol, 2003; 49: 532-8).
Lung cancer, too, is a not uncommon effect of breast radiotherapy. Of 31 patients who had received radiotherapy for breast cancer, a staggering 19 went on to develop lung cancer - mostly on the same side as the irradiated breast (Med Oncol, 1994; 11: 121-5). Breast cancer patients also risk having soft-tissue cancer of the breast (Int J Radiat Oncol Biol Phys, 1995; 31: 405-10) and heart damage.
There is no evidence that radiation therapy for DCIS saves lives - 'no trial in patients with DCIS has ever shown a survival benefit with the use of radiation,' says Dr Melvin Silverstein, director of the University of Southern California Breast Center in Los Angeles (Oncology [Huntingt], 2003; 17: 1511-33).
In addition to drug therapy and radiation, conventional treatment for DCIS also includes surgery - either the removal of a small area of tissue or the whole breast. And in the opinion of breast specialist Michael Baum, the very act of piercing the flesh may cause cancer to develop.
Baum points to the theories of Harvard researcher Dr Judah Folkman, who has shown that cancers spread by forming new blood vessels via a process called 'angiogenesis'.
As angiogenesis also occurs whenever flesh is injured, this may be enough to trigger the cancer process. 'The newly formed blood vessels [after an incision] bring the blood and oxygen that encourage tumour growth,' says Baum. 'They also provide the means for cancer cells to travel to distant organs and form new tumours.'
Baum believes that biopsy can also precipitate cancer. This routine diagnostic technique uses a needle to pierce the skin and cut out a tiny sample of tissue.
'If you identify these latent DCIS cancers and biopsy them, you have traumatised the area,' he says. 'You immediately trigger the natural healing mechanisms which involve angiogenesis. So the biopsy could be considered as an angiogenic switch. You take a latent cancer that would never hurt a woman, biopsy it, turn on the angiogenic switch, and it ceases to be latent - it becomes an aggressive disease.'
The evidence appears to bear Baum out. Three separate studies show that breast cancer 'almost always occurs at the original biopsy site' (Cancer, 1986; 57: 197-208; Cancer, 1989; 63: 618-24; Br J Cancer, 1990; 61: 869-72).
Poor track record
The third arm of breast-cancer treatment sometimes used for DCIS is chemotherapy, where powerful cell-destroying drugs are infused into the bloodstream. In this case, Swedish cancer statisticians did the massive job of marshalling together all the evidence from over 200 separate trials of the world's major chemotherapy drugs.
The most positive news they could find was that chemotherapy reduces death rates in some breast cancer cases by, at best, 12 per cent. But, for most women with the disease, chemotherapy fares very much worse.
The open secret in medicine is that the conventional treatments for breast cancer, as with DCIS itself, is still a largely a mystery. Despite all the fanfare about winning the war on cancer, the best statistics still come from alternative practitioners.