It is impossible, these days, not to be aware of cancer. The diagnosis and the clinical course of prominent political figures and of movie stars are carefully detailed in the newspapers. A football player develops acute leukemia, and sport columnists discuss whether he should participate in competition. The President of the United States has an abdominal operation, and the Nation is uneasy until physicians testify that no cancer was found.
At the level of the common citizen, there are few families in the United States who have not had personal experiences with cancer. This is almost inevitable, because now cancer is the number two scourge of our people, destined during the whole of our lifetime, of 70 years, to afflict one of each five of us, and to send one of each eight of us to the grave. It is a measure and the price of our victories over some of the original horsemen of Apocalypse. The pale rider of pestilence is now retired, and the cadaverous rider of hunger is too obese to maintain his seat. We now face different riders, one in the shape of a mushroom cloud, and one in the shape of a crab.
Great credit is due to the intelligence of the American people for removing many of the taboos and secrecies that surrounded cancer just a few decades ago. We now accept openly and write freely that human beings have rectums and vaginas, and that diseases of any cause and any part of our body require public knowledge. We are now better informed and resultantly stronger. Secrecy and ignorance lead to fear. And, as Shakespeare said, fear is more pain than is the pain it fears.
The other side of the picture of better public information is the complexity and the unending volume of technical reports that are often presented without adequate background. Issues of scientific journals, announcements from scientific institutions, meetings of scientific societies produce a torrent of reports that are boiled down for use by newspapers, and carried throughout the world by the news services. New cancer tests, new causes of cancer, new drugs that are claimed to have produced remissions of cancer are thus presented to the public eye. The stories are soon forgotten, because too many are overinterpreted or out of context. Science seldom advances by great leaps, or by massive breakthroughs that are announced at meetings. Its processes are usually much slower, through the accumulation of information and verification by many workers, until a definite step of progress becomes evident to all. By then the step may be considered no longer newsworthy by journalistic standards. This happens so often that one facetious physician once divided accounts of scientific discoveries into two classes : the dramatic, unimportant ones, and the undramatic, important ones.
One reason why this is true is that it takes time to establish the proper place of many observations within the framework of science and medicine. A new treatment for cancer is described. If this treatment were truly useful, the author must be able to present what has happened to his patients several years later. If he does not have such information, he must wait for the necessary years to elapse.
But the patient who has cancer now, and the physician who must decide how to treat that patient now, cannot wait several years for the conclusion. For the decisions that have to be made now for ourselves and for those who depend on us, we must separate carefully the best information that is available from the hopeful trends that may lead us to better answers in the future.
What can we do, and what should we do, about cancer? And what are the research scientists finding and developing in the laboratories and clinics? These are the two questions with which this report is concerned, and which it attempts to answer in the light of our current knowledge.
But, to start at the beginning, what is cancer?
First of all, cancer is a word in the English language, derived from the Greek word for crab, karkinos. Among its many synonyms are malignant tumor and malignant neoplasm (from the Latin for new growth) . Subgroups of cancer, describing the body tissues of origin, include carcinoma, sarcoma, melanoma lymphoma, and many other related or combined terms.
Cancer is a word that stands for a great group of diseases that afflict man and animals. Cancer can arise in any organ or tissue of which the body is composed. Its main characteristics include an abnormal, seemingly unrestricted growth of body cells, with the resultant mass compressing, invading and destroying contiguous normal tissues. Cancer cells then break off or leave the original mass and are carried by the blood or lymph to distant sites of the body. There they set up secondary colonies, or metastases, further invading and destroying the organs that are involved.
This semi-independent behavior of cancer cells, in contrast to the disciplined behavior of normal cells that allows them to fulfill functions useful to the body, is called autonomy.
Another important characteristic of cancer is its appearance under the microscope. The individual cells vary in size and shape, and the orderly orientation of normal cells is replaced by disorganization that may be so complete that no recognizable structures remain. This loss of normal appearance is called anaplasia.
At the present time, cancers are classified by their appearance under the microscope, and by the site of the body from which they arise. By such criteria of appearance (morphology) and localization, devised by pathologists during the past century, at least 100 different cancers are identified. The number can be increased to 200 or more if finer details of morphology are taken into consideration.
There are, of course, other differences between cancer entities. Some cancers grow very slowly, and destroy neighboring tissue by local invasion. Others are very aggressive and disseminate rapidly to distant sites. Most cancers occur with increasing frequency among older people, but some forms of cancer are found most often in children. About some cancer entities we know much and can prevent their occurrence. About many cancers, our knowledge regarding cause is still entirely lacking.
Thus, cancer is a group word that encompasses many different entities that are dissimilar in appearance, in behavior, and undoubtedly in the causative factors as well. Cancer as a word therefore shares in the difficulty common to all group words: it is a convenient general term that must be used carefully when we are dealing with specific situations. In an intelligent discussion of cancer as a clinical problem of an individual patient, or as a research topic of an experimental animal tumor, we must identify the specific type of cancer and the specific conditions of the situation. These specific conditions should not be extended to other cancer entities, or to the whole group of cancers, if confusion and misunderstanding are to be avoided. Many of the seeming paradoxes regarding cancer can be attributed to the extension of the specific to the general, on the one hand, and the application of the general to the specific on the other hand.
For convenience, we have discussed cancer and normal cells as two sharply separate, different entities. Actually, there is a wide spectrum of cellular abnormalities and normal reactions between these extremes. The rate of cell division and tissue growth of a normal pregnancy exceeds the rate of growth of many cancers, with the key difference being that the normal process stops when it has reached its end point. In appearance also, the normal repair of injured tissue may for a time look quite “wild” under the microscope, but represents a self limiting reaction. There is also a spectrum between the benign, or innocent, tumors, and cancers, including a zone of borderline lesions regarding which decision is particularly difficult. Later we shall have occasion to refer to “incomplete,” and to “dependent” tumors, cellular growths that are intermediate in their behavior between the innocently benign and the malevolently malignant cancers. As a further complication, a tumor that may be benign in microscopic appearance and in behavior can be fatal if located in a vital area or in a limited space, such as the brain.