Part 4

Cancer is practically always preceded by chronic irritation of some kind or other. There may be, and in fact are, other factors which enter into the problem, but there can be no doubt that in nearly all cases there is what may be called a precancerous stage, which, if adequately dealt with, will often prevent cancer appearing at all. It is moreover a longstanding chronic condition which, as a rule, gives rise to very little inconvenience on the part of the patient.

After this precancerous stage there appears what may be called early cancer, often indistinguishable to the naked eye from the original precancerous lesion, but giving rise to great suspicion in the eyes of the initiated on account of its hardness, and tendency to be fixed, and its resistance to treatment. Cancer in this stage can be cured, with results which will compare favourably with the cure of any other known disease (i.e., in about ninety per cent. of all cases) its cure simply depending on early diagnosis. This is a fact neither known nor appreciated by the general public, and until it is known by everybody, and these early stages are radically dealt with, we shall still be spending our time and money looking for new and miraculous cures for a condition which, in its very nature, is unlikely to be susceptible to any method of cure when its late stages are reached.

The third stage is that in which the neighbouring lymph glands are involved. In this stage about thirty per cent. are incurable, but these figures are not of much help or comfort to any particular sufferer as they depend on the degree of involvement and the rapidity of growth. There is, in the vast majority of cases, no reason why it should ever reach this stage other than those causes which are within the control of the patient and his doctor.

Lastly we get to a stage in which the disease is frankly inoperable, and generally speaking, only capable of relief by one palliative measure or other. About forty to fifty per cent. of all cases which reach the surgeon have already arrived at this stage, and it is to this fact that the generally hopeless attitude of everybody is to be attributed. It is only when this stage is reached that the patient has pain and symptoms which “wake him up,” and that he realises the calamity which has befallen him.

The early signs of cancer may now be summed up as those of a lesion of some kind, extending over a number of years, giving rise to very little trouble or inconvenience, and followed by a small hard lump or ulcer. If the latter is present, it is often characterised by bleeding. Again, practically no symptoms. To find it we must look and see; often an operation involving practically no suffering and a very small mortality is necessary. But the penalties of failure to do this at the proper time are that ten per cent. of the population die of cancer.

There are certain popular misconceptions about cancer which require correction. The first is that cancer is necessarily painful. This is responsible for much of the late diagnosis, operative mortality and the bad results. Only late cancer, and it would not be far wrong to say only incurable cancer, gives rise to pain. If only pain were an early sign of cancer the whole aspect of the cancer problem would be changed.

Another very widespread delusion productive of great harm is that cancer is constantly associated with wasting, and makes rapid progress. These two symptoms are constantly associated with the disease in its latest stages but are not seen at all in early cases.

One frequently hears people say that cancer is contagious, and also that it is hereditary. These two popular conceptions probably have the same basis. As we have seen, cancer is a very common disease, and it would be strange indeed if, putting all question of relationship on one side, we were not to see it quite commonly occurring in one or more members of the same family, and if occasionally we did not find a house in which each successive occupant for some years had cancer. I will leave it to the mathematicians to work out the probability of cancer occurring more than once in any given family. The necessary figures are easily obtained from the Registrar-General’s office. As far as I know, there is nothing truly in the nature of what may be called evidence in support of either of these notions.

Time after time people have described parasites of some kind as associated with cancer, but none of them has yet been made to answer to any of the tests necessary to establish anything more than a casual correlation. It may turn out to be that the causal agent in cancer formation is a parasite either visible under the microscope, or, what is more likely, belonging to the group of ultravisible, or filter-passing, organisms; but even if this be so, there are two other factors of immense importance, found so constantly associated with the disease, that their significance cannot be underestimated by anyone whose outlook is any wider than that of the mere purveyor of prescriptions.

These two factors may be considered in a little more detail, as they are of importance with regard to the question of prevention. They are (1) the presence of an acid environment, and (2) what, for want of a better term, may be called chronic irritation. Whatever the prime cause may turn out to be, these can never be left out of account in any consideration of aetiology, and even if some specific cause is found, the discovery will not shake the validity of my thesis.

For two thousand years people have speculated about the origin of cancer. Galen held a theory somewhat analogous to the present Chinese doctrine of the yin and the yang; he taught, in essence, that some kind of “ch’i” had got at loggerheads with its fellow gases, and that the result was a general disturbance of bodily functions. Paracelsus thought that the salt balance of the body was upset, and textbooks still sometimes put this into modern medical terminology, saying that the balance of power between different types of cells is disturbed. This may or may not describe what happens, but it is a long way from explaining it.

In the sixteenth and seventeenth centuries cancer was often referred to as an “act of God” in punishment for sin. For instance, cancer of the tongue was said to afflict those who spoke against the Church, a view that the Church, not always strictly scientific in interpretation of phenomena, did not discourage.

Here is a translation which Sir D’Arcy Power has made from Paul de Sorbant, a German physician writing in 1672, in his Universa Medicina. “We saw”; he says, “an ulcer of the tongue degenerating into cancer in the noble baron Vertemali, which caused such a haemorrhage from destruction of the sublingual arteries and veins that the patient was suffocated. He recognised with great penitence that the cause of this cancer was a divine punishment because he had often abused the clergy.” Benetus, about the same time, in his book called Medicinae Septentriniolanus Collatitia, describes a case of what he calls “Tumor Linguae Miraculosa.” Here is a translation of part of it. “There was lately a certain baron who had a very poisonous tongue. He not only directed his jibes against all and sundry, but he kept his most venemous shafts for the clergy and those who devoted themselves to God’s service. He was caught at last in the very act, by a holy brother of good repute as he was pealing this cursed bell, who said to him: ‘Your foul tongue has overlong deserved that punishment from an offended God which it will shortly receive.’ The Baron went off undismayed, but a few days afterwards a small swelling began to grow on the side of his tongue. Little by little it increased in size until it became an inoperable cancer, and at length the tongue having become incurved, twisted and drawn back to his throat, miserably afflicted, but penitent and confessed, he was summoned before the Great Judge who calls his servants to a most strict account.”

This may all seem very far away and out of contact with our present-day thought, but only two years ago a dear old lady sent to the Cancer Hospital Research Department two pages of closely written typescript, the gist of which was that she was withdrawing her usual annual subscription, as, after giving the matter a great deal of thought, she had come to the conclusion that cancer was caused by the consumption of alcohol. So she proposed to forward her usual subscription to the local Temperance Society which really was striking at the root of the problem! The Secretary wrote and pointed out that cancer is very common in cats who are strict prohibitionists! The old lady did not reply!

Let us come back again from theory to fact, and consider some of the factors which we know constantly to be associated with cancer, and which we are justified in regarding as being, in many cases, more than predisposing causes.

The most important of these is chronic irritation. We find that almost every cancer is preceded for a longer or shorter period by what may be called a precancerous condition. The more our knowledge increases the more we are finding out that this holds good.

The commonest sites for cancer are the womb, the breast, and the stomach. These together account for more than sixty per cent. of all cancers, and far below them in frequency we find the tongue, the lip, and the bowel, and the various glands.

Cancer of the womb is constantly preceded for many years by disease, palpable and curable, often the result of childbearing, and the part where it occurs is one bathed in an acid medium.

Cancer of the breast also is constantly associated with preceding chronic inflammation, this condition itself producing, as one of its by-products, a highly acid substance, further to irritate the delicate cells already near the end of their tether. Mechanical irritation, beyond a doubt, is an important factor. Although in civilised countries the disease is distressingly common, in those countries where the breasts are habitually uncovered, cancer of this organ is extremely rare. The habitual friction of modern clothes predisposes cell-growth, infection from no matter what source is given a foothold, and after years of abuse, the cells lose the impulse to normal reaction and at last turn and slay their victim.

There is evidence that about two-thirds of all the cases of cancer of the stomach originate in an old gastric ulcer, and the constant eating of hot food is perhaps enough to account for the remaining third. The delicate gastric cells, more abused than any other cells in the body, are bathed in a highly acid medium. It is no wonder that departure from their appointed path accounts for thirty per cent. of all cancers in men, and in women as well, if we except the two conditions just mentioned.

In cancer of the kidney, the bladder, and the gall bladder, stones are nearly always present to initiate the irritation.

In cancer of the tongue, syphilitic or other preceding conditions are nearly always there, whether it be the irritation from raw alcohol, hot tobacco smoke, or a broken tooth. It is interesting to note that, until syphilis appeared in Europe, cancer of the tongue was practically unrecorded in the existing literature. We have no need to go any further for examples of these precancerous irritative conditions. They are all curable or removable, but, as they do not as a rule give rise to acute painful symptoms, severely inconveniencing the patient, they are difficult to treat, and the unfortunate patient is told to wait and see, and is given medicine which may for a while relieve, but which――alas!――seldom has a chance to cure, or to prevent the fate which is slowly overtaking him.

So far the evidence which has been brought before you, that chronic irritation has a causal connection with cancer, has been of a circumstantial nature: it has often enough been found in what we may call suspicious circumstances, but that does not prove that by itself it can directly cause the disease. If a man is seen hanging about the place where a burglary has been committed, it does not prove that he participated in it. He may be a burglar, or he may be what lawyers call an accessory before the fact, and before we can feel reasonably sure that he is a guilty party we must, unless we can actually see him committing the crime, find that whenever he is present, and he has a chance, a burglary takes place.

Now in scientific investigation we can do what in ordinary life is not possible; we can take our burglar, arrange a set of suitable circumstances and see what happens and with what degree of regularity thefts occur. In the last four or five years something like this has been done on a large scale with cancer, and a large body of evidence is accumulating which suggests that, given suitable circumstances, chronic irritation will produce cancer with a fair degree of regularity, at least in some places. If it will do so in some places there is no reason to doubt that, under circumstances which for the moment we do not quite understand, it will do so in all the places where cancer is found.

That this is so has not yet been completely proved, but I think there is a good deal of evidence along this line. It has been known for a great number of years that certain skin cancers are constantly found in people whose occupations necessitate their skin being in contact with certain chemical irritants. For instance, the workers in shale oil are often afflicted with cancer of the skin. In the spinning industry, when reaching over to deal with the machinery, a place on the worker’s leg is always rubbing up against an oily spindle. This process goes on for years at the same spot, and these people are found frequently to get cancer, beginning at the irritated place. Some aniline dyes are excreted in the urine, and growths of the bladder are very frequent in aniline workers. In India, some native tribes carry little metal boxes containing charcoal next to their skin in order to warm themselves, and the warmed spot frequently becomes the seat of a malignant ulcer. Further, in chimney-sweeps, whose skin is always more or less impregnated with carbon, we find that cancer frequently develops in those places where the soot is difficult to wash completely away and often is not cleaned off for years at a time. Finally, we have the well-known examples of skin cancer among X-ray workers, and mouth-cancer in those who chew betel nut.

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.