Definition

An epithelial neoplasm of the intestinal walls.

Etiology

The etiology of intestinal cancer, like that of cancerous disease of other organs, is still unknown. The traumatic theory (repeated irritation of one particular area) appears quite plausible with reference to this organ. As will be seen later, this malady occurs much more frequently in those parts of the bowels in which the passage of fecal matter is more apt to be retarded, and in consequence to cause irritation.

With regard to sex, it is generally accepted that intestinal cancer occurs somewhat oftener in men than in women. With reference to age it is chiefly met with during the period from forty to sixty-five years. Cancer of the intestine is occasionally found also in young people, this happening much more commonly than cancer of the stomach or of other organs. Nothnagel 1 has observed cancer of the caecum in a twelve-year-old boy, and Schoening 2 reports two cases of rectal cancer in girls seventeen years old.

1 H. Nothnagel: "Die Erkrankungen des Darms und des Peritoneum, " Wien, 1898. 2 Schoening: Deutsche Zeitschr. f. Chirurgie, Bd. xxii., 1885.

According to Maydl,1 the total number of intestinal cancers occurring from the first to the thirtieth year amounts to one-seventh of the entire number of cases.

Location

With regard to location the frequency of the affection in the different portions of the bowel varies. The frequency gradually increases the lower down the growth is situated, beginning with the jejunum and ending with the rectum. Among one hundred and sixty autopsies on cases of cancer of the different organs, Maydl found in one hundred cancerous disease of the bowels. In one hundred and ten autopsies of patients suffering from intestinal cancer, Bryant 2 found the neoplasm located six times within the small intestine, seven times in the caecal and ileocaecal regions, nineteen times in the transverse colon, including the hepatic and splenic flexures, seventy-eight times in the sigmoid flexure and rectum. Maydl gives the following locations of the tumor in one hundred autopsies: Two in the duodenum, four in the ileum (none in the jejunum), forty-six in the large bowel (in the vermiform process, one; caecum, nine; ascending colon, six; colon seventeen; sigmoid flexure, thirteen), and forty-eight in the rectum. As regards cases observed during life, Maydl gives the following figures: During twelve years there were in the Wiener Allgemeines Krankenhaus 246,827 patients. Among these there were 6,287 patients with cancer.

Among the latter there were 254 cases of cancer of the bowels, and in 224 of these the neoplasm was in the rectum. This certainly shows the great predilection of intestinal cancer for the rectum.

Intestinal cancers are almost always primary. It is exceptional for cancer of the bowels to develop by way of metastasis. It is obvious, however, that cancer in this region may develop secondarily as a result of direct extension of the cancerous process from a contiguous organ. This often occurs in cancer of the stomach, gall bladder, or pancreas. Intestinal cancer often gives rise to metastases in other organs. According to Muller,1 these are more frequently met with in cancer of the small intestine than in that of the large bowel. The lymphatic glands are also often secondarily affected. Those in the neighborhood of the neoplasm show a greater tendency to become cancerous than those farther off.

1 Maydl: "Ueber den Darmkrebs," Wien, 1883.

2 Joseph D. Bryant: Annals of Surgery, February, 1893.

Morbid Anatomy

All varieties of cancer are found in the intestines. Most frequently, however, the cylindrical epithelial-celled carcinoma, having a glandular structure (adeno-carcinoma), is encountered. The latter takes its origin in the epithelial cells of the follicles of Lieberkuehn. Colloid carcinoma is quite often found in the rectum, while melano-carcinoma is here quite rare. Occasionally the pavement-celled carcinoma (epithelioma cancroid) is met with, especially in the lower part of the rectum, starting principally from the anus. It often involves the perineum and the vagina.

The neoplasm varies in consistency according as connective tissue or cells predominate. If the former is the principal element, then the tumor presents a hard consistency (as hard as cartilage) and is termed scirrhus. In case the latter are more abundant, then it is less firm, occasionally soft and succulent. The colloid cancer as a rule contains a brownish, somewhat viscid fluid. The scirrhus shows a greater tendency toward partial necrosis in its central part. It often forms a carcinomatous ulcer.

The primary intestinal cancer frequently shows a tendency to extend in a circular direction perpendicularly to the lumen of the bowel. Stenosis of the intestinal canal is very often the result of this circumstance. In case the stricture is of marked degree, the intestine above the stric-tured spot becomes greatly distended through stagnating fecal matter and gas. The bowels working hard to overcome the obstacle show thickened walls due to hypertrophy of the muscles. The irritating and stagnating contents in the dilated part of the intestine give rise to catarrhal inflammation and also to ulcers. If the stenosis has become still more pronounced, the dilatation of the intestine above it may be so excessive that a rupture of its walls ultimately occurs. Below the stricture the intestinal wall appears thinner, and if the stricture is so narrow that no contents pass downward, it appears empty and contracted. Occasionally the neoplasm constricting the intestinal lumen begins to break down and ulcerate, and this partly removes the occlusion of the intestinal canal. This, however, does not last long, for as a rule the cancer shows a tendency to grow again and to fill up the defect.

Thus the free lumen of the bowel is very soon again occluded.

2 Max Muller: "Beitrage zur Kenntniss der Metastasenbildung ina-ligner Tumoren." Inaugural-Dissertation, Bern, 1892.

This partial necrotic process will also often cause more or less hemorrhage through erosion of the smaller bloodvessels. In case a larger artery or vein opens, a severe hemorrhage with fatal issue may result.

Cancer of the bowel often involves, besides the mucosa and submucosa, the muscularis and even the serosa. In the latter event perforation occurs in rare instances before adhesions have had time to form, and may result in fatal general peritonitis. In most instances, however, adhesions have formed around the involved area, and thus the perforation causes merely a circumscribed peritonitis. Even without the occurrence of perforation the cancer may progress from the serous layer to the peritoneum and lead to a carcinomatous peritonitis, which is often accompanied by a hemorrhagic exudation. Another series of grave complications is caused by the extension of the cancerous process to a neighboring organ which has previously become agglutinated to the bowel. The process of disintegration in the cancerous growth then often establishes an abnormal communication between the bowel and other organs. Thus fistulous openings may occur between colon and stomach, between rectum and bladder, between rectum and vagina, between rectum and uterus, between large and small bowels, or a direct fistulous opening may form from the bowel through the abdominal wall.

Symptomatology

Cancer of the bowel develops quite slowly and insidiously, and in most instances at the beginning gives rise to hardly any symptoms at all. For this reason it can never be detected at this time; later, however, general and local symptoms manifest themselves. While the general symptoms are common to all cancers of the small and large bowels, the local symptoms will differ according to the location of the tumor, and it will therefore be necessary to consider the different portions of the intestinal tract separately.