Counting the cost
MEDICINE.
JOHN ROWAN WILSON
We are constantly being told that the future of medicine lies in the earlier diagnosis of disease, and particularly of cancer. As everyone knows, the reason why people die of malignant disease is because of its tendency to spread, either directly through the tissues, or by the lymph channels to the lymph glands, or by the blood stream. It would seem logical to suppose that the earlier the cancer is recognised, the better the chance of removing it surgically before it has time to get out of hand
A good example of this is cancer of the female breast, which is likely to spread by any of the three methods. It is a Common growth, in a re- latively accessible site. It presents as a painless lump which can be felt as a hardening of the ordinary texture of the breast. Such a lump is not always cancerous—it may be a benign non- spreading growth. The accepted technique of management nowadays is to remove all such lumps by a small operation and examine them microscopically. If they turn out to be benign, no harm is done. If the cells are malignant, it is probably wiser to remove the breast.
The problem is to find the lump early enough. Because it is painless, it may 'be some time be- fore the woman notices anything abnormal. One of the methods by which it is hoped to increase early detection of breast cancer is by encourag- ing all women, particularly of middle age and over, to examine their breasts once a month and to attend their doctors if they notice any obvious changes in consistency. Obviously they will sometimes go to their doctors unnecessarily, but this seems a small price to pay if the occasional cancer can be picked up at an early stage when it would otherwise have gone unnoticed.
Another method of early diagnosis has been introduced in the last few years. This is by means of X-ray examination of the breast, or mam- mography as it is called. By taking X-rays of the breast from various angles it is sometimes possible, to spot a change in the consistency of the breast tissue which cannot be felt by the hand and yet which turns out to be a growth when-removed at operation. The question arises whether it is worth while using mammography in the same way as mass X-rays of the chest, as a routine screening test for normal women.
A study has been carried out in New York to assess the value of routine mammography. Just under 20,000 women received clinical examination and mammography. Forty-nine breast cancers were picked up. Twenty of these were diagnosed on physical examination alone, another twenty could be seen on the X-ray; nine were found on both clinical and X-ray exami- nation. Just under half the cases found were considered to be early cases—that is to say, there was no evidence of spread to the lymph glands.
This is, of course, a much more elaborate, and time-consuming business than simply asking women to examine their own breasts periodic- ally. If it were made a routine procedure it would lead to a very considerable burden on the National Health Service. It raises the same difficult question which is posed by so many screening procedures for picking up early dis- ease; is it of sufficient value, in a sufficient num- ber of patients, to justify the cost in terms of finance, resources, and manpower?
This is a distasteful question, when human life
Is at stake, yet so long as resources are limited it has to be asked. On the evidence of this study, twenty-nine out of the forty-nine cancers would have been discovered by a simple examination. The other twenty can be credited to the X-rays. This is significant but it is only one positive re- sult in a thousand It is questionable whether this would be considered justified on a nation- wide scale. •
Nor is it very easy to assess how much bene- fit is brought to the patient. Only half of the cases diagnosed were found to be early cases. And the value of early diagnosis of breast cancer is also less than it might be because of great differences in the degree of malignancy of individual growth. Some growths spread very quickly and others with great sluggishness. This may be due to the nature of the cells of which the growth is composed, or it may be due to variations in the immunity of the body and the defence it sets up against the extension of the disease. This means that if a cancer is highly malignant, early diagnosis will probably not help very much, since it will probably be lethal no matter how soon it is discovered, and if it is of low malignancy, the outlook is good even if it is picked up very late. Indeed some figures show a very encouraging prognosis for growths which are diagnosed late. The reason is that if they were not growths of loir malignancy the patients would have been dead some time ago.
It has been argued by some surgeons that these variations in malignancy make early diag- nosis relatively unimportant. They suggest that the 'early case' is a myth, since it does not give any indication of the malignant potential of the growth. They point to the undeniable fact that survival rates for cancer of the breast have not noticeably improved over the last generation, in spite of the great improvement in medical services and the facilities for early diagnosis. There may be something in this. Yet one can- not help feeling that if those who support this argument found a malignant growth in their own bodies they would be inclined to have it removed as soon as possible. Most doctors would say that early diagnosis is of value in a proportion of cases of breast cancer, enough to justify the simple periodic examination of women of their own breasts. But probably not, as things stand at this moment, to justify more elaborate screening procedures.
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