Treatment Of Large Bowel Cancer.

If diagnostic studies do confirm the presence of large bowel cancer, the patient ordinarily will be admitted to the hospital for further preparation and treatment. The problem is not really an emergency, and a waiting period of up to a few weeks before admission does no harm unless the intestine is partially obstructed. Since patients with large bowel cancer are usually older, the assessment of other organ systems, such as the heart or lungs, will also be necessary. Modern surgery, however, is so well developed that all but the most seriously ill patients can do well, albeit with a somewhat increased surgical risk, if there are significant heart or lung problems.

If the patient is to have a rectal operation, special studies such as an X-ray study of the kidneys, ureters, and bladder (a pyelogram) may be necessary to determine their positions and whether they too have been invaded by cancer. In addition, other blood and radiologic studies such as brain, liver, and bone scans may be performed to be as sure as possible that the tumor is limited to the large bowel and that the odds for a cure are good. As might be expected, these preoperative studies are not carried out in cases where obstruction or perforation have occurred.

Preparing the large bowel for operation requires thorough cleansing with enemas followed by oral antibiotics, usually one with an erythromycin base and neomycin, on the day before the operation. Safe surgery of the large bowel demands having a clean, dry colon. Therefore both strong laxatives and enemas must be used to ensure that the colon is well prepared for the operation. Patients also are asked to go on a special diet in preparation for the surgery. This entails eating low-residue foods that produce little stool, followed by a full liquid diet and, finally, a clear liquid diet. This part of the preparation can begin before admission to the hospital or the patient may be admitted two or three days before the operation, at which time the dietary preparation will begin. Since some diarrhea will be produced by this regimen, extra fluids are needed to make up for the fluid loss.

The main objective of the operation is to remove the tumor and a wide border of colon both above and below the cancer as well as the lymphatic tissue that drains it. With rare exceptions, such as cases in which there is serious infection or inflammation of the bowel, the continuity of the intestine is restored by rejoining the ends, a procedure known as anastomosis. Thus the colon, even though somewhat shorter than before, will function normally following the surgery. If an anastomosis cannot be performed at the time of the cancer surgery, a temporary colostomy—a surgically created opening between the colon and the outer surface of the body—will be made. After healing has taken place, this will be repaired, restoring normal colon function.

If the cancer is in the rectum, it may be necessary to form a colostomy. Although many people have the mistaken notion that large bowel cancer inevitably means a colostomy, it is now actually the exception rather than the rule. Over the last twenty years, a variety of operative techniques have been developed, and now only about one of seven patients with rectal cancer requires a permanent colostomy. Techniques for restoring the continuity of the bowel include a very low anastomosis, an anastomosis from the floor of the pelvis (the perineum), or in some instances, a local removal of the rectal cancer through the anal canal. Occasionally after a low anastomosis is performed, a temporary colostomy may be needed to protect the area from infection until healing has taken place. In these instances the colostomy will be closed in an operation two or three months after the initial cancer surgery.

In recent years it has become clear that for some patients, radiation therapy provides additional benefits in treating rectal cancer. In some instances the radiation therapy may take place before the surgery; in others the operation may be performed first, with the course of post-surgery radiation to be determined by the exact nature of the cancer found during the operation. In either instance, proper timing of the radiation in relation to the operation is important to achieve the maximum benefit of both and to ensure proper healing following the surgery.

In some instances drug treatment also may be recommended following surgery for large bowel cancer. These treatments known as adjuvant, or supplementary, chemotherapy may add an additional element of protection to those patients with more extensive tumors, or those whose cancers may have spread to other parts of the body. In adjuvant chemotherapy, the anticancer drugs are given orally or intravenously or both, periodically for up to several years after the surgery. These drugs may be given even if there is no evidence of spread beyond the colon, depending upon the extent of the cancer.

After the operation the surgeon will be able to tell the patient and his or her family the visible extent of the tumor. About three to five days later, the pathologist's report on the microscopic nature of the tumor will be submitted. This report ordinarily will classify the tumor specimen by the Dukes staging system, named for a London pathologist, Cuthbert Dukes, who developed the classification system in 1932. Since that time some modifications have been made. In general, a Dukes A tumor has not penetrated through the full thickness of the bowel wall. The cure rate of a Dukes A tumor exceeds 90 percent. In a Dukes B tumor, the cancer has penetrated the full thickness of the bowel wall, but lymph nodes are not involved. The cure rate in these cancers is about 70 percent. If there has been spread to the lymph nodes, the likelihood of cure diminishes and in these circumstances patients may be advised to have additional radiation therapy, chemotherapy, or both.

Immediately following an operation for large bowel cancer, the patient can expect to have a plastic tube placed through the nose and into the stomach to drain secretions. This tube will remain in place for several days, and during that time no food will be given by mouth. Instead, all nourishment will be intravenous. The surgical staff will examine the patient's abdomen regularly, and when normal bowel sounds return, oral feeding gradually can resume. This process normally takes four to seven days.

When patients with a cancer in the sigmoid colon or rectum are operated on, there is often also a temporary paralysis of the bladder as a result of the operation on the rectum, which is close to the nerves that serve the bladder. These patients must have a urinary catheter in place for several days after the operation until the paralysis subsides and normal urination resumes. In many instances patients actually prefer the catheter, because it spares them the discomfort or pain in their wound associated with standing up to urinate or moving around in bed to use the bedpan.

After a major abdominal operation a patient can ordinarily expect pain at the incision, but in decreasing intensity, for about two days. The pain will be effectively blunted by painkilling drugs. For an additional two days the patient can expect pain in the wound or incision when he or she turns, coughs, or moves about. After about four days there is no pain at all.

A patient who has had colon surgery with an anastomosis and restoration of intestinal activity can expect to leave the hospital about eight days following the operation. By that time the patient will be able to eat solid foods, the antibiotics will have been discontinued, and strength regained. A further convalescent period will be required at home, but, in general, regular work can be resumed about six weeks later, although many patients who do paper work will resume part-time activity promptly, often while still in the hospital. Upon stretching, some pain may occur at the site of the scar, but this will go away in a few months.

When it has been necessary to remove the entire rectum, the patient will have two incisions one on the abdominal wall and one at the perineum, the area between the coccyx (tailbone) and the genitals. Ordinarily the lower wound is closed completely, but on occasion it is necessary to keep it open and pack it with sterile packing material. The pack will be removed about five days after the operation, and the area will then heal. When the rectum must be removed and a colostomy constructed, a longer hospital stay is required, often extending up to fifteen days or more, before the patient is able to return home for continued convalescence.