The conquest of cancer

by H. W. S. Wright

Now it is just this type of cancer that we have the opportunity to imitate in the laboratory. Dr Leitch, of the Cancer Hospital, has taken rats, guinea-pigs and rabbits; and, day after day for months, soot, tar, oils and all the irritants he could think of were respectively painted on some selected part of their bodies. At the Cancer Hospital he started using tar to paint on the under surface of the bodies of white mice. This was done every morning for several months, and, in a large percentage of cases, small warts were produced. The fate of these warts varied; some of them disappeared, but others progressed to the formation of true cancer. The results of these experiments made it extremely probable that the irritants were the direct cause of the cancer. Of course it is not proved, for it is possible to assume that there is some ubiquitous “other cause”, only waiting till the tissue resistance is lowered enough by the irritants to get its chance to act. Another interesting fact, which transpired as the result of this work, is that some of the animals from whom the warts disappeared developed cancer a month or so subsequent to the disappearance, thus showing that the predisposition to cancer formation is acquired long before the growth actually appears.

In human beings, the process of cancer formation in response to chemical irritants takes much longer (often twenty to thirty years), and is preceded by much the same sort of preliminary skin reaction as in animals.

In looking for a proximal cause for cancer production, we should not, I think, look for a common cause in all cases, but should try to find something or anything which will produce the necessary previous irritation.

It has not, I think, been established beyond a doubt that chronic irritation is the sole exciting cause of cancer—this in the nature of things would be very difficult to prove—but it has been shewn that its presence strongly predisposes to new growth formation.

The problem which now arises is that of how we are going to put this knowledge we have gained to practical use in the prevention of cancer. In order to solve this we will consider in some detail the three commonest cancers met with, namely cancer of the breast, the womb and the stomach, and we will see how the problem applies to them.

Now in cancer of the breast we have this outstanding fact that, almost all the cases show for some years beforehand obvious signs of chronic inflammation of the breast, and in nearly all of them this precancerous stage can be seen, when they are examined microscopically.

Obviously this is the time to deal with the disease; and the way to do so is systematically to examine microscopically (by a procedure in itself devoid of all risk, except the very small one due to the administration of a general anaesthetic), every doubtfully malignant breast, afflicted by chronic inflammation. This may seem a revolutionary thing to say; but if we set ourselves to deal with this plague in the logical manner that we employ when we sit down to deal with any other pest, and, if we follow all the facts known to their inevitable conclusion, we are driven to it, and we shall see that there is no other course open to us but to deal in a wholesale manner with the precancerous condition. To do this we shall have to undertake a long campaign of education. One of the leading authorities on breast cancer in America, did undertake such a campaign in his own district, with the result that, from the enthusiastic propaganda of one man, the proportion of precancerous to fully developed malignant lesions which appeared at his clinic rose in six years by thirteen per cent. In twenty years the proportion of fully developed cancer to pre-malignant lesions dropped from ninety to seventy-eight per cent.

I am quite sure of the fact that the adoption of this proposal would mean operations upon a number of breasts which would never become cancerous, but, so far as I can see, we cannot help this, any more than we can help vaccinating a large number of people who will never have small-pox, or, when we isolate diphtheria contacts, can we help disturbing also a large number of people who will never get diphtheria. The public have been educated to regard these precautions as natural and proper, and as a rule raise no objections to their being carried out. Dr Bloodgood, to whose educational work I have just referred, states that if any woman could be kept under sufficiently close observation, she could be practically assured against death from cancer. I think every other surgeon of experience would agree with him.

So much for prevention and the precancerous lesions. Let us come to the question of the cure. Here we find that the chances of cure in any particular case simply depend on the stage at which the case appears for treatment. We can for convenience divide cases into two groups; those which have glands involved and those which have not. By this I mean those which have glands so grossly involved that they are appreciable to the touch. Again quoting Dr Bloodgood, it is found that of those cases with gland involvement, twenty-three per cent. only are cured after seven years but, of those without gland involvement, sixty-five per cent.

Now, here is the fact which ought to rouse us to action: the average duration of the disease in these cured cases was nine months—nine precious months in which that remaining thirty, or forty, per cent. might have been cured if they had only been treated earlier. Or, if they had been properly examined still earlier by a trained person, the disease could have been dealt with earlier with a still better chance of ultimate cure, and it is Dr C. H. Mayo who has said that there is no reason on earth why about ninety-five per cent. of all cases of cancer of the breast cannot be permanently cured.