ONE does not have to labor the point in order to prove that every layman should know the facts about a murderous malady second only to heart disease as a killer. According to an eminent statistician, cancer has increased 70 per cent in twenty-five years, taking every year, in the United States, a toll in excess of the number of American soldiers killed in action and dying from wounds during the World War, exempting no type of individual, no race, no nationality, and no terrain, attacking man and animals, — cold-and warm-blooded,— respecting neither youth nor age nor station.
Medical men characterize the furnishing of such facts as ‘educating the layman.’ Frankly, we have been hard put to it to determine just how far we have a right to go in this venture of broadcasting information about cancer. Every earnest student of the disease knows that the subject holds within itself no small amount of hope, and yet he is literally confounded when it comes to reconciling hope with the gloomy train of facts stated in the paragraph above. It may be said to the enduring credit of medicine that as a rule leaders in the field of cancer research do not varnish verity. Within a very recent period, three outstanding investigators of cancer have expressed themselves in such frank sentiments as: ‘In the theoretical field the results have been most impressive, but in practical results fundamental cancer research has been disappointing’; ‘The medical profession as a whole is not yet prepared accurately to diagnose the disease at a stage which permits of effective therapeutic attack’; ‘ Probably we have all the facts of cancer, but we are like children gazing at a starry sky — the stars that are so bright to us may be very small worlds, and those that we barely see may be infinitely great.’ Scientific candor can furnish no more emphatic avowal than do these quotations that, in this field at least, there is no chance for demonstrating the Johnsonian theorem of the triumph of hope over experience.
I happen to be in full agreement with Dr. Zinsser’s revolt against the presentday obsessive tendency to popularize science. But such a reaction as ours is in no conflict with the basic wisdom of fostering right thinking, or of applying a corrective for wrong thinking, concerning a vital subject around which there cluster so many popular misconceptions. The average intelligent layman believes that cancer is a hopeless disease, that it is distressingly painful, that it is hereditary, foul, and offensive, and, therefore, a shameful disease; and finally, that not enough is being done by the medical profession to get at the bottom of the whole mess.
Right here is the time to say that these notions illustrate the remarkable fact, pointed out by Josh Billings years ago, that most people know a lot of things that are not true. Cancer is not a hopeless disease; it has not been proved to be hereditary in the human family; it is not always distressingly painful — as a matter of fact, it is often, unfortunately, unaccompanied by a warning pain; it is not a foul and shameful disease; and finally, a tremendous lot is being done about it.
One could scarcely lay down the proof of all the above truths within limits less than those of a good-sized treatise; but one might hope for the acceptance of most of them in the mere faith that they rest on warrantable even though unstated evidence. Our purpose here is merely to expound the thesis that scientific medicine, keenly alive during the past quarter of a century to the seriousness of the problem, has done much about it. The very essence of such an exposition demands that the expositor and his listeners or readers should start out with a common understanding and the establishment of a common ground by careful definition of terms and no less careful arrangement of perspective.
Regarding terms, the most important objective is to clarify the confusion of thought that centres around the distinction between cancer and tumor. Indeed, the story of cancer cannot be told divorced from the story of tumor, because the Latin word tumor, meaning ‘swelling,’ antedated the Latin word cancer, meaning ‘crab.’ The ancients noted that certain particularly malignant tumors invaded the tissues in which they grew by sending out into them prolongations of tumor growth. These infiltrating tendrils resembled, in plan, the offshoots of the legs from the body of the crab. Therefore this particular type of tumor was called crab, in Latin cancer, on the basis of its naked-eye appearance. Of course this crablike structure was a tumor or swelling, but it was a particularly malignant type of tumor that tended to defy cure and kill the patient.
A cancer, then, is a type of tumor so malignant that, if not destroyed in time, it causes the death of the individual harboring it. Every cancer is a tumor — so much is clear. It is not always so easy to grasp the fact that not every tumor is a cancer. And yet it becomes very simple if we call to mind the analogy with snakes: every cobra is a snake, but not every snake is a cobra. Just as there are countless nonvenomous serpents in contrast with the various poisonous species, similarly there exists a large variety of benign tumors outside of and distinctly separate from the malignant cancer group.
And now for the question of perspective. It may be considered perfectly good form to outline the activities of scientific medicine in the field of cancer, during the past quarter of a century, without even referring to what the future holds in her lap. Indeed there is comfort in maintaining honor by sloughing prophecy. But no one could pretend to make a thoroughly intelligent assay of recent activities in the field of cancer without sketching a vague background of the accomplishments of the past. Nature works her wonders, in part, through mutations or jumps. Science by contrast, with the rarest exceptions, plods painfully along, laying stone on stone in her ever incomplete structure. It therefore is imperative to have a concept of the foundation if one entertains the hope of appreciating or of understanding the superstructure.
There are authentic records to show that for six thousand years medicine has been engaged in the problem of unriddling cancer. The very earliest efforts in Egypt amounted to little more than rather clumsy thinking; but the men of classic Greece and Rome made some first-rate observations as regards the use both of drugs and of the knife; and if they did nothing else they established for all time the fact of the malignity of the disease. More than that, they rooted a set of ideas and opinions, which, inadequate as they were, nevertheless dominated medical thought for much longer than a thousand years.
Medical men did not begin to reason in thoroughly rational fashion about the disease, however, until the seventeenth century, when they were jolted into independent thinking by a combination of the intellectual impetus furnished in general by the same agencies that led to the Renaissance and in particular by Harvey’s epochal discovery of the circulation of the blood. The fact of the matter is that all the early independent thinking about the subject of cancer yielded nothing basic, but merely a somewhat more adequate general concept of the disease. The probable explanation of this sterility of thought may be the fact that nobody attempted to examine cancers microscopically. It is one of the curiosities of medicine that although the microscope was trained on everything conceivably small, as early as 1700, no one thought to use it in studying tumors until nearly the middle of the nineteenth century (1838), when the great German biologist, Johannes Müller, showed that tumors were made up of cells similar to those that constitute the normal organs and tissues of the body. It is not difficult to conceive the flood of light that this discovery shed on the whole subject of tumors, or to grasp the significance of the even more striking discovery made by Rudolf Virchow, twenty years later, demonstrating that all tumors may be classified into groups according to the cells that constitute them. Virchow showed that it was possible with the microscope not only to separate tumors into groups, but also to determine which of the tumors were cancers.
From this point up to the beginning of our own century, nothing striking was accomplished. One almost feels that scientific minds were lying fallow, preparing themselves for the brilliant third of the twentieth century, just completed. As no one had thought to use the microscope on cancer until Müller showed the way, so also no one had conceived the idea of producing cancer experimentally until an American, Leo Loeb, announced in 1901 that he had succeeded in grafting tumors in animals. This discovery marked the introduction of the present era of experimentation in cancer.
Briefly, what Loeb did was to snip off the tiniest bit of tissue from a tumor growing spontaneously in a rat and to transplant this bit of tumor under the skin, at another site, in the same rat, or into another of the same species. As a result of this seemingly simple experiment, we have been able to study, in animals, such questions as the rapidity of growth of tumors, their method of spread or dissemination, and the factors that increase or diminish the resistance of animals to the growth of tumors. We have never been able to study the growth of cancer of human beings by the procedure of transplantation into animals, because tumor transplants will grow only when they are placed in the bodies of animals of the same species as the one from which the transplant was taken. We have, however, during the last very few years, mastered a delicately intricate technique whereby we succeed in growing bits of human cancer under glass, on specially prepared artificial media that serve as a nutrient on which the cancer cells grow. The studies based on this new procedure are too recent to warrant any dogmatic conclusions.
In the attempt to disclose the cause of tumors, parasites of all varieties have been investigated, from the lowly louse all the way down to those parasites that infest such insects as the cockroach. Bacteria have been studied so thoroughly that the papers published on this subject would stack many library shelves. Filterable viruses are living substances of some sort, so small that they defy the microscope. Among other damages that they cause is the development of certain kinds of warts; and, since warts are tumors, cancer investigators have been studying these filterable viruses for almost a quarter of a century. Embryonic cells have been intensively studied as a possible cause of cancer, because, if a very young embryo is minced up and injected into the body of an animal of the same species, the injected cells will maintain an independent tumorous growth.
It is natural to assume that possibly a chemical of some sort provokes tumor growth, so, on the basis of that suspicion, countless drugs and chemicals have been studied. Among these, coal tar furnished one of the most dramatic episodes in the search for the cause of cancer. It had been known for years that chimney sweeps were prone to cancer of the groin and scrotum, where the tarry soot particles lodged in the creases of the skin. It was likewise known that workers in the tar industry developed cancer of the skin. But it was not until 1914 that two Japanese experimenters, after applying tar to white mice for months at a time, discovered that cancers could be produced at will in these little animals. Aniline oil, mineral oils, paraffin, arsenic, and various coal-tar derivatives have also been found to be cancer-producing substances in mice, rats, guinea pigs, rabbits, and monkeys. This so-called experimental production of cancer opened up a vast new field and has greatly enlarged our fund of information even if it has not led to a solution of the problem.
The glands of internal secretion have been known for a long while to be bound up closely, in some way, with the mystery of growth. Since tumors represent abnormal growth, an immense amount of work has been done on the possible relationships existing between tumor formation and the functions of such internal secretory organs as the thyroid, thymus, pituitary, pancreas, adrenal, pineal, parathyroid, and sex glands. Although this work has not yet yielded specific results even approaching such brilliant accomplishments as the discovery and use of pancreatic extract (insulin) in the treatment of diabetes or of liver extract in the treatment of pernicious anæmia, it nevertheless embodies potentialities that are stirring to contemplate. This is particularly true since the biological chemists have shown, within comparatively few months, that there is a close chemical relationship between the products of the glands of internal secretion and that radical in coal tar which causes experimental cancer. Just by way of adding further glamorous hope to this chapter, the chemists likewise have demonstrated that Vitamin D, another growth-producing agent, bears to tar a close chemical relationship similar to that between tar, our most potent cancer-producing chemical, and the internal glandular secretions.
Cutting, burning, bruising, and various other types of deliberately produced injuries, inflicted on anæsthetized animals, have been studied in great detail, because in human beings injuries of various sorts are not infrequently followed by the development of a cancer at the site of the injury. So also the less readily appreciated irritations in humans have been investigated, such, for example, as those due to stones in the gall bladder, the urinary bladder, and kidneys, or to the abrasions of the tongue by jagged teeth, or of the mouth by badly fitting dentures, or the irritation that results from chronic inflammation of any sort in any part of the body. Even the irritation that might possibly result from eating overhot food has been studied.
Since cancer of the skin is more frequent in those countries blessed with most sunshine, such as the tropics; and since cancer of the skin is also more frequent in those nontropical individuals who are unduly exposed to sunshine, such as farmers, sailors, bargemen, and lightermen; and since, furthermore, colored people have cancer of the skin less frequently than do white people, possibly because their skin pigment protects them against light — since all these are facts, an intensive study has been made and is being made of the relation of light to cancer. No less intensive has been the study of x-rays and radium, those two weird agencies that possess the power both to cause and to cure cancer.
Such are some of the possibilities that have been and are being investigated. The list is admittedly incomplete. (I have, for example, made no mention of a very sober communication, submitted about two years ago to one of the important cancer research journals of the world, to the effect that cancer is the response of the body to a libidinal need!) Incomplete as it may be, however, the list will serve two purposes, in that it furnishes an idea of the breadth of territory covered and affords an opportunity to say just a few words regarding the element of romance that colors the picture of the intensive search for the cause of cancer. Seldom does one lind a more thrilling story than that of how Fibiger discovered that a hitherto undescribed tiny worm, infesting the gastrointestinal tract of the cockroach, caused cancer to develop in the stomach of rats. This particular variety of cockroach was unknown on the continent of Europe, where Fibiger lived and worked, and yet he was able, by what has been called a combination of good fortune and false clue, to track down the offending worm by demonstrating that some American cockroaches that had reached Denmark in a cargo of sugar carried the infecting worm in their intestines, and that the worm caused cancer of the stomach in rats that ate the excrement of the cockroaches.
No less is the imagination stirred by the fact that the great German physiologist-chemist Warburg, after fabricating laboratory apparatus that was fairylike in some of the details of its design, was able to prove that cancer cells, instead of oxidizing glucose as do normal cells, reduce it to lactic acid by a process of fermentation. This is only a technical way of saying that Warburg showed that the microscopically small cancer cells, although practically identical in appearance with the normal cells of the body, nevertheless live and breathe differently.
These romances are, in the end, tinged with tragedy, in that, say what we may regarding the glamour of these past twenty years of cancer research, admire as we may the zeal, the concentrated effort, the buoyancy of hope, the recalcitrant refusal to entertain the idea of defeat, the indomitable will to conquer, and the enormous amount of factual data that has been assembled and proved — the unadorned truth is that, in stark reality, we seem to be only a little nearer to the provocative agency or agencies of cancer than were our medical forbears of sixty centuries ago.
The solution of the cancer problem constitutes a twofold task, involving as it does the discovery of the cause and the elaboration of preventive or curative measures. Although simple candor compels the admission that the cause still lies concealed, a no less measure of frankness demands that pessimism should not color the picture too darkly; for we may discuss the chapter of prevention and cure in tones that are vibrant with cheer and hope. Beyond all question of doubt, many patients, either threatened or actually affected with the disease to-day, will live well beyond the Biblical span, in good health, provided that they enjoy the privileges of proper advice and treatment.
This truth gives evidence that medicine has won a signal victory against heavy odds. Cancer cells are frequently more resistant than are the normal cells of the body to most of the ordinary destructive agencies; therefore, in our attempts to do away with cancer, we always face the danger of destroying vital structures in which the cancer grows, and of which it constitutes an integral part. Picture the difficulty in the way of so firing a volley into a flock of sheep that only the black sheep are destroyed! Such is the basic complexity of the problem of cancer cure; and yet, as a result of the striking progress that has been made in the fields of surgery, preventive medicine, and radiotherapy (x-rays and radium), the problem is being unraveled.
In lieu of quoting dry-as-dust statistics, it may be in order to lean again on the faith of the reader, telling him that the percentage of cures and the marked degree of amelioration that characterize present-day treatment of cancer arc almost incredible. The percentage of cures in cancer of the skin, breast, womb, larynx, pharynx, and lips has been elevated steadily to a point not even hoped for ten years ago. More than that, progress is in the making in the treatment of cancer of the brain, bladder, and lung — organs whose involvement, a decade ago, signified a death warrant. How clearly manifest it is, therefore, that if, on the one hand, we frankly admit failure in the attempts to demonstrate the specific cause of cancer, we may, in the very next breath, glory over the increasing incidence of cures and the improvement of procedures aimed at ameliorating life for those who cannot be cured. Surely all this means that ‘something is being done about it.’