We have thus seen while cancer is very widely distributed over the globe it is present in varying degrees of severity in different localities, and careful analysis shows that the disease affects different classes of persons with unlike severity. All these statistical studies and observations serve to confirm the statement made earlier that cancer is a disease of so-called civilization, and that it has increased in proportion as human beings have come under the influence of wealth, and consequent luxury and overindulgence, with bodily inactivity; all these elements lead to a disturbed metabolism, which as we shall see later, is, at least, a contributing cause to the deviation from normal of some of the cellular elements of the body. It also appears that some of these metabolic shortcomings have to do with a disturbed nitrogenous balance, which is due to the constantly increased consumption of meat. In 1909 the meat consumption in the United States had reached the high figure of 172 pounds per capita, as I learned recently from Washington, a far greater amount than in England, 130 pounds, as already stated; and with this steady increase in the use of nitrogenous food cancer has also increased by leaps and bounds in both countries.
LECTURE III
METABOLISM OF CANCER
In the first lecture we saw that cancer was an alteration of the normal cells of the body, whereby they take on a malignant action and continue to do so, destroying contiguous tissues and leading to a lowered vitality, with an apparent poisoning of the system, which finally causes death. As the cells of various organs furnish different secretions, which in health contribute to proper metabolism, resulting in growth or maintenance of the tissues, so these disordered cells are believed to secrete a toxic substance, or malignant hormone, which has a prejudicial action on the body, and hæmolytic action on the blood, as has been brought out pretty clearly by Troisier and others.
We saw that as yet the definite cause had not been determined, why at some period certain cells take on the action which we call cancer, nor why they persist in their destructive course. Long continued and abundant laboratory and clinical research have about decided certain questions negatively in regard to its etiology, so that in a measure the field is cleared for the study of some of the possible basic causes of the disease in question. Thus, all are pretty well agreed that cancer is not contagious or infectious, that it is not caused by a micro-organism or parasite, that it is not wholly due to local injury, that it does not appertain to any particular occupation, that it is not hereditary to any great degree, that it does not especially belong to or affect any particular sex, race or class of persons, nor is it confined to any location or section of the earth, and that it is not wholly a disease of older age.
We saw further that there appeared to be good evidence that certain misplaced “embryonal rests” were the original starting points of diseased cell action, but as these are now known to exist in every one from birth, this offers no real explanation of the occurrence of the disease at different times in life. It is, of course, quite possible that local injury of one kind or another may be the exciting cause which determines that a cell or group of cells shall revert to its original reproductive activity, as Williams contends that the process is one of agamogenesis, dependent upon excessive and faulty nutrition. The question as to the relation of uricacidæmia, or lithæmia, to cancer has never been fully studied, and it is worth considering whether, as in gout and rheumatism, to which cancer is often associated and perhaps closely allied, the exciting cause may not be the lodgment somewhere of uratic deposit, which is further excited and fed by effete or imperfectly oxidized nitrogenous elements; for later we shall see that perverted metabolism, largely of proteid elements, is closely associated with cancer.
We noted also that some attributed cancer to independent cell action, relating to the polarity of cells, etc.; but it is inconceivable that a cell or cells can idiopathically start out on a rampant course and pursue it with increasing severity, even until death results, without, at least, some definite pre-disposing cause, even though diligent and earnest work has not as yet determined just what that cause may be. The error has been, we believe, in searching too exclusively by the microscope and by certain laboratory methods, and not sufficiently along clinical and bio-chemical lines. For it must be recognized that all the cells of the body are continually bathed in the vitalizing fluid of the blood, whence they derive their nutriment, and into which, with the lymphatics, they return the products of their vital action, by anabolism and catabolism.
By exclusion, therefore, we are reduced to seek the etiology of cancer along other lines, and about all that is left is metabolism, as influenced by advancing, so-called civilization, which relates very largely to diet and mode of life. This we will take up later, but will first examine some of the scientific findings in regard to the blood in cancer, and data relating to the various secretions and excretions of the body bearing upon metabolism in this disease.
That the blood shows great changes in advanced cancer is recognized by all, as is clinically manifested by the intense cachexia and anæmia commonly present and always strongly marked toward the end, of which the cytology has been very fully studied and presented by Türk. When then examined there is found to be a marked reduction of red cells, low hæmoglobin index, and distinct leucocytosis, with greatly diminished alkalescence.
The reported changes in the blood have also varied with the location of the malignant disease, according as it may interfere mechanically or otherwise with the function of certain organs, which fact naturally obscures the question of the true relationship of the blood to cancer. Thus, it is stated that in cancer of the liver and pancreas there is always leucocytosis and glycogen, and that “cancer appears to interfere greatly with the function of the liver as a destroyer of intestinal toxins, they pass into the general circulation, probably cause the glycogen reaction, and at least part of the leucocytosis, and very often give rise to fever.” There are also other microscopical alterations in the blood in late cancer. Thus, degenerative change in the leucocytes are common, with derangement in the normal proportion of their different forms, as also changes in the erythrocytes, with nucleated red cells and megalocytes in severest cases.
Price Jones in a study of the blood in 30 cases of cancer (9 of the breast) found the red blood cells diminished on an average of 6 per cent., the white blood cells increased 38 per cent., lymphocytes increased by 10 per cent., large mononuclear cells increased 164 per cent. and polynuclears 42 per cent. Burnham states that in the severe grades of anæmia with malignant disease, poikilocytosis is marked, and nucleated cells of both normoblastic and megaloblastic type may be present. The red corpuscles may be reduced to 2,500,000, and exceptionally to 1,000,000. Cohnreich in a very technical study of blood from cancer subjects, observed very great increase in the resisting power of the red blood cells to osmotic tension, that is, in regard to their hæmoglobin, which he believed to be of diagnostic value in doubtful cases.