Any portion of the intestinal tract is liable to be attacked by cancer, though undoubtedly some parts of it with much greater frequency than others. Köhler3 reported that in thirty-four cases the cancer was situated twenty-two times in the large intestine (the rectum excluded) and twelve times in the small intestine (nine times in the duodenum). It is not unlikely that in the cases of duodenal cancer the new growth extended from the pylorus. At all events, primary cancer is seated with far greater frequency in the large intestine, and, not including the rectum, usually in either the sigmoid flexure or the cæcum. Grisolle4 declares the large intestine to be four times more often affected with cancer than the small intestine; that the sigmoid flexure is attacked as often as all the rest of the colon taken together; and that the cæcum is still more often affected. Where the intestinal new growth is secondary to carcinoma elsewhere, it is usually so by extension from neighboring parts; thus, the ileum may become implicated by contact with uterine cancer, etc., and cancer of the stomach, liver, kidney, etc. may invade the colon.
3 Ibid., vii. p. 431.
4 Pathologie int., 1865, ii.
Cancer of the intestines usually begins after the middle period of life, and apparently irrespective of sex. Nevertheless, young persons are occasionally affected, and children sometimes develop malignant new growths of the bowels (usually sarcomatous), either primarily, which is rare, or secondarily, by extension from other parts. The influence of heredity seems not to be well established. There can be no doubt that chronic irritation may act as an exciting cause of cancer of the bowels, as it may in cancer of other parts. It has been impossible to recognize any specific influence from especial forms of irritation, and it is not likely that such exist. Indeed, the etiological relations of intestinal cancer remain exceedingly obscure.
SYMPTOMATOLOGY.—Up to a certain period of development cancer of the bowels will give no sign of its presence; indeed, cases have been observed where, death having occurred from other causes, the existence of the malady became apparent only at the necropsy. In all cases the symptoms are, at first, of an indefinite character and very inconstant. Vague abdominal pains are experienced; these gradually tend to become referable to a certain locality and to become associated with irregular action of the bowels. Constipation, alternating with short intervals of diarrhoea, supervenes, and a varying amount of meteorism is developed. These symptoms may be attended by the signs of failing nutrition. The body gradually shows the effects of chronic imperfect assimilation, and becomes emaciated. The complexion slowly assumes the peculiar hue of chloasma cachecticorum. Long before this occurs, however, the cancerous new formation usually becomes perceptible as a more or less distinct abdominal tumor, movable or fixed, as the part affected permits of free movement or is bound down to the neighboring parts either by normal attachments or by adhesions resulting from inflammatory processes or from the extension of the cancerous growth. When the tumor is movable, it is generally situated in the small intestine or transverse colon or sigmoid flexure, the other portions of the intestinal canal being comparatively fixed. It should be mentioned, however, that portions of the intestines normally freely movable may become adherent to contiguous parts, as the transverse colon, with the gall-bladder, liver, stomach, spleen, etc. etc.; the transverse colon and small intestine, drawn down by the weight of the new growth, with the pelvic organs, the bladder, uterus, uterine appendages, etc.; and that, finally, different portions of the bowels may become involved in one mass.
When the duodenum is the portion implicated the tumor may escape observation or may be indistinguishable from cancer of the pylorus. It occasionally happens that no tumor can be discovered until the malady is far advanced whatever part of the bowel is affected. In nearly all cases, however, before very long the tumor will be detected wherever situated, but it will often remain difficult, owing to its situation, to arrive at exact conclusions as to its precise character. Usually, it offers considerable resistance to the touch, but its features may readily be obscured by the fecal accumulation that forms above the constricted portion of the gut and by the gaseous distension of the bowel. This tumor will be slightly painful to pressure, and the patient will refer to it a spontaneous pain, usually of a dull aching, sometimes of a stabbing, character. Percussion yields a sound of muffled resonance, due to the tubular nature of the tumor. Cancerous neoplasms of the bowel, and of the duodenum especially, are apt to be associated with a distinct pulsation caused by the subjacent abdominal aorta. This may readily be distinguished from aneurismal pulsation by the absence of an expansile character, by the disappearance of the impulse that may sometimes be observed when the patient is made to kneel upon all fours, and by the occasional mobility of the cancerous tumor. By extension and by inflammatory infiltration the tumor frequently becomes converted into a conglomerate mass where all determination of locality becomes conjectural. The tumor is, with very rare exceptions, single.
The symptoms that accompany the development of these growths depend mostly upon their position in the alimentary tract. Pain alone seems independent of this, but is at best a most uncertain concomitant. When the duodenum is the part affected by extension from the pylorus, the symptoms are indistinguishable from ordinary pyloric cancer. Even primary cancer of this part may exactly simulate pyloric cancer. The localized pain and tumor, the vomiting after meals, the frequent presence of blood in the vomited matters, the progressive emaciation from starvation, the absence of abdominal distension (a result of the constriction of the gut at its upper extremity), the gastric dilatation,—all combine to make the diagnosis difficult.
Cancer of the duodenum in its descending part may be suspected when signs of hepatic and pancreatic obstructive difficulties point to implication of the ducts, through which are produced jaundice upon the one hand, and evidences of imperfect pancreatic digestion, in the presence of undigested fat in the stools, upon the other. In the lower portions of the intestines the cancer becomes more and more associated with meteorism and fecal accumulations. Constipation becomes steadily more obstinate, but there are occasional fluid evacuations containing blood, pus, and mucus, often stinking abominably. When the tumor is toward the end of the large intestine—in the sigmoid flexure, for example—fluid discharges occur with very great frequency at times; but these are scanty in amount and but slightly fecal in character. In these cases one does not usually observe the compressed, ribbon-like stools that are seen in rectal cancer. These symptoms may precede the appearance of the tumor, when the diagnosis will be less readily made. The constipation will at first be more amenable to the use of purgatives. (It is said to be due more to a loss of contractility of the bowel than to the narrowing of its lumen.) Gradually these will lose their efficacy, and finally complete obstruction of the lumen of the gut is effected; in which event the symptoms of ileus will develop, with cramps and vomiting, finally of a fecal character, and the fatal issue quickly follow. Not unfrequently peritonitis is developed, and may be of a chronic character or may destroy life within a day or two, or the patient may die from exhaustion before the obstruction becomes complete.
It may happen that the integument will become involved in the malignant process, or may become continuous with the tumor by adhesive inflammation. In such cases an opening may be formed by suppuration, or the lancet may secure the passage of feces through an artificial anus, and temporary respite be obtained. Sometimes a sudden disappearance of the symptoms of obstruction—a result due to the softening and breaking down of the cancerous mass, restoring temporarily the integrity of the intestinal tube—may give an unjustifiable hope to the patient; or the same effect may follow the establishment of a communication, by ulceration, between the bowel above the tumor and some portion nearer to the anal orifice. The progress of the new growth soon annuls the benefits thus gained.
Not uncommonly, particles of the cancerous mass may become detached, and, if diligently searched for, may be discovered in the feces. Microscopic examination may then definitely determine the nature of the disease. It has been claimed that colloid cancer may be diagnosticated in this manner even before the appearance of other symptoms.5 Death may be hastened by the occurrence of metastatic deposits in other and vital organs. Oedema of the lower extremities (of the left extremity in cancer of the sigmoid flexure) will often be observed as a result of the interference of the cancerous mass with the return of blood from the extremities by pressure upon the large veins. The combination of pain, tumor, constipation, tympanitis, progressive wasting, and the cachexia that sooner or later supervenes, stamps eventually most cases with unmistakable characters.