CANCER, or CARCINOMA (from cancer, or ______, an eatihg ulcer), is the name given to a class of morbid growths or tumours which occur in man, and also in certain of the lower animals. The term is apt to be somewhat loosely employed, partly owing to the fact that there are not a few forms of diseased growth respecting which it is still a matter of debate whether they are to be regarded as. cancerous or not ; and in some measure also to the diffi-culty often experienced in recognizing true cancer particu-larly in its earlier stages.
The disease exists in various forms, which, although differing from each other in many points, have yet certain common characters to which they owe their special signifi-cance.
1. In structure such growths are composed of nucleated cells and free nuclei together with a milky fluid called cenoer juice, all contained within a more or less dense fibrous stroma or framework.
2. They have no well-defined limits, and they involve all textures in their vicinity, while they also tend to spread by the lymphatics and veins, and to cause similar growths in distant parts or organs called " secondary can-cerous growths."
3. They are undergoing constant increase, and their progress is usually rapid.
4. Pain is a frequent symptom. When present it is generally of a severe and agonizing character, and together with the local effects of the disease and the resulting condition of ill health or " cachexia," hastens the fatal termination to which all cancerous growths tend.
5. When such growths are removed by the surgeon they are apt to return either at the same or at some other part.
The chief varieties of cancer are Scirrhus or hard cancer, Encephaloid or soft cancer, and Epithelial cancer.
Scirrhus is remarkable for its hardness, which is due to the large amount of its fibrous, and relatively small propor-tion of its cell elements. It is of comparatively slow growth, but it tends to spread and to ulcerate. Its most common seat by far is the female breast, though it sometimes affects internal organs.
Encephaloid is in structure the reverse of the last, its softness depending on the preponderance of its cell over its fibrous elements. Its appearance and consistence resemble brain substance (hence its name), and it is of such rapid growth as to have given rise to its being occasionally termed acute cancer. Its most frequent seats are internal organs or the limbs. Ulceration and haemorrhage are common accompaniments of this form of cancer.
Epithelial cancer is largely composed of cells resembling the natural epithelium of the body. It occurs most frequently in those parts provided with epithelium, such as the skin and mucous membranes, or where those adjoin, as in the lips. This form of cancer does not spread so rapidly nor pro-duce secondary growths in other organs to the same extent as the two other varieties, but it tends equally with them to involve the neighbouring lymphatic glands, and to recur after removal.
Various views are entertained, and much discussion has taken place respecting the causation of cancer, but little lias as yet been satisfactorily ascertained on the point. By some the disease is held to be from the first an entirely local affection, due to some alteration in the nutrition of the part, irrespective of any condition of the system gene-rally, but in course of time coming to assume a malignant form, and to infect the system secondarily. Others, on the contrary, maintain that a certain constitutional condition, either as regards the blood or some of the tissues of the body, must exist prior to the development of the disease to which it gives rise. A third view is that the concurrence of a constitutional and a local cause is necessary for the production of cancer Without entering into an examina-tion of these opinions, it appears evident that a constitu-tional element cannot be excluded in view of such well-known facts as a hereditary liability to cancer, and also of its occasional appearance in several parts of the body at one time.
The hereditary tendency in some persons to this disease has long been recognized by medical men; but its extent was not accurately ascertained till Sir James Paget affirmed, as the result of his observations, that in one out of every three cases of cancer a family history of the malady could be traced, and further, that even this probably does not represent the whole extent of the hereditary predisposition to cancer.
Cancer is essentially a disease of degeneracy, all statistics going to show its. relatively great frequency after middle life; and the mortality, according to Dr Walshe, goes on increasing with each decade until the eightieth year. Cancer may, nevertheless, attack persons of any age, and instances of its occurrence are not unknown even among young children. It affects females to a much larger extent than males,—this, however, being fully explained by the greater liability of the female breast and of the uterus to the disease than any other organs of the body; for, apart from this, cancer is quite as common among men. It occurs equally among all ranks of life.
The commencement of a cancerous growth is frequently attributed to some local injury, as in the case of blows on I the breast, or in the well-known instance of cancer of the lip following the irritation produced by smoking a short : clay pipe. But it is only as exciting causes that the I influence of such injuries can be admitted; and there must I still remain, as necessary to account for the disease, some antecedent condition of the system which gives the par-ticular direction to the form of morbid action in the part.
Cancer tends to advance steadily to a fatal termination, but its duration varies in different cases according to the part affected, and according to the variety of the disease. Soft cancer affecting important organs of the body often proves fatal in a few months, while, on the other hand, cases of hard or epithelial cancer may sometimes last for several years; but no precise limit can be assigned for any form of the disease. In some exceptionally rare instances cancerous growth may exist for a great length of time, and undergo a kind of spontaneous cure, or at least prolonged arrestment.
With respect to the treatment of cancer the only hope of success lies in the entire removal of the disease. This can obviously be only accomplished where the growth affects parts which are within reach of the surgeon. When in such cases the tumour is of recent formation, is limited in its extent, does not largely affect the neighbouring lymphatic glands, and has not as yet produced any marked deterioration of the general health, the surgeon is warranted in operating. Although it must be admitted that the results are generally disappointing from the intense tendency of the disease to recur sooner or later, yet the relief to suffering and the prolongation of life obtained are alone sufficient to justify operative interference when other-wise admissible, not to mention the fact that in some rare instances a cure has thus been achieved. Nor is the view of the constitutional and hereditary nature of cancer necessarily inconsistent with the adoption of such remedial measures,—since, from the analogy of other hereditary diseases, it is probable that these influences are more potent at certain times of life, and that by prompt treatment the period of special liability may be tided over, although the inherent tendency cannot be eradicated. When from the extent of the disease or its existence in internal organs no attempt at removal can be made, all that can be hoped for is the relief of suffering, and it is certain that even in such circumstances much may be done by appropriate medical treatment. It is painful to think how many of the unfor-tunate sufferers from this malady place themselves in the hands of ignorant persons who profess to be able to cure cancers, but whose violent remedies, if they do not actually destroy life, as has often been the case, only aggravate, suffering and entail disappointment.
Cancer is known to occur in many of the lower animals, being probably most common among the domestic tribes, but it presents no special peculiarities as a disease beyond those already referred to. (J. O. A.)