Sir, - Let's hope the teachers pictured on the front page of your edition of December 6th weren't on their way to a spelling test. Obviously, being completely unaccountable, they probably feel that they don't need to worry about getting the little things right. These university graduates were going on a high-profile rally that was obviously going to be conducted in the full glare of the media, yet they could not be bothered to check their spellings. How can we be sure that they do not inflict the same lax standards on the pupils they "teach"? - Yours, etc.,
Gavan Fagan, Ard Ross Avenue, Carrickmacross, Co Monaghan.
Breast Cancer Screening
Sir, - Prof Niall O'Higgins (November 15th), as chairman of the National Breast Cancer Advisory Group, succinctly described the two-pronged approach of screening and centralised treatment in an effort to reduce the high mortality from this disease in Ireland. It seems intuitive that finding small breast cancers and removing them surgically should reduce mortality. Mammography shows breast cancers that are impossible to palpate.
On September 16th last, the British Medical Journal was able to publish the statement that "there is no evidence that clinical examination. . .or teaching self-examination of the breast are effective tools for early detection. . .Randomised controlled trials have shown that screening by mammography can significantly reduce mortality from breast cancer by up to 40 per cent in those who attend. The benefit is greatest in women aged 50 to 70 years."
But by the end of that month, results of the Canada-2 randomised controlled trial of mammography refuted that assertion. That trial compared the outcome in 39,405 women who had been randomly assigned to one of two groups. One group had mammography and a detailed 10-minute breast examination and the other had the detailed breast examination only. After 13 years, there were 107 deaths from breast cancer in the mammography group and 105 deaths from breast cancer in the physical examination group only. However 71 pre-invasive "in situ" breast cancers were found by mammography, against 16 by palpation only. The work was published in the Journal of the National Cancer Institute. The authors concluded that, for women over 50, thorough annual physical breast examination may be a useful alternative to mammography. Skilled attention to relatively minor physical signs in most important. Furthermore, in women between 50 and 59 years, the addition of annual mammography to physical examination has no impact on breast cancer mortality.
In February last in the Lancet, Gotzsche and Olsen questioned whether screening for breast cancer with mammography was justifiable. They reviewed mammography trials using the evidence-based Cochrane Library database and claimed that six of eight identified randomised controlled trials were methodologically flawed. The results of the Malmo and Canada trials that passed stringent randomisation criteria allowed the authors to conclude that there was no reliable evidence that screening decreases breast cancer mortality.
An age cohort study from Britain also published in September last claimed that mammography reduced breast cancer mortality by about 6.4 per cent and that improvement in treatments and earlier diagnosis were responsible for a reduction in mortality of about 14.9 per cent. However, this was a study comparing observed mortality against that predicted for the same group of people, so it does not have the same validity as a randomised trial.
Breast cancer should be kept in perspective. Data from the Ontario Cancer Registry show that from a birth cohort of 1,000 women, an average of 17 will die before the age of 40, none from breast cancer. In their 40s and 50s, 54 women will die, nine dying from breast cancer and nine from heart disease. In the 60s and 70s, 305 women will die, 105 from heart disease and 18 from breast cancer. By 85 years of age, 203 women will have died from heart disease and 33 will have died from breast cancer. Lung cancer due to smoking is as big a risk for women as breast cancer, yet cigarettes are included in the consumer price index despite the proven relationship between price and consumption.
Thus I agree with Prof O'Higgins about the benefits of specialist treatment centres for women with breast disease. But what does his group say about the sceptics' case regarding mammography? Has mammography merely acted as a conduit for the improvement of breast cancer treatment and, hopefully, outcome without being of itself beneficial? - Yours, etc.,
Bill Tormey, Glasnevin Avenue, Dublin 11.