Colorectal Cancer Information - Causes, Symptoms And Treatment

Alternative name :- Colon cancer

The colon and rectum are part of the large intestine (large bowel). Colon and rectum cancers, which are sometimes referred to together as "colorectal cancer," arise from the lining of the large intestine. When cancer arises from the lining of an organ like the large intestine, it is called a carcinoma .

Colorectal cancer is the second most common visceral malignant neoplasm in the United States and Europe. It's the third most common cancer in women and the second leading cause of cancer death. Incidence is equally distributed between men and women; however, it's estimated that, in 2003, over 100,000 new cases of colon cancer were diagnosed and almost 54% in women. Colorectal malignant tumors are usually adenocardnomas. About half of these are sessile lesions of the rectosigmoid area; the rest are polypoid lesions.

Colorectal cancer tends to progress slowly and remains localized for a long time. Consequently, it's potentially curable in about 90% of patients if early diagnosis allows resection before nodal involvement. With improved diagnosis, the overall 5-year survival rate is about 60% for adjacent organ or nodal spread, and greater than 90% for early, localized disease.

What Causes Colorectal Cancer?

The exact cause of colorectal cancer is unknown, but studies showing higher concentrations in areas of greater economic development suggest a relationship to diet (excess saturated animal fat). Other factors that magnify the risk of developing colorectal cancer include:

• other diseases of the digestive tract . age (over 40)
• history of ulcerative colitis (average of 11 to 17 years between onset of ulcerative colitis and onset of cancer).
• familial polyposis (cancer onset almost always by age 50).

Symptoms of Colorectal Cancer

Signs and symptoms of colorectal cancer result from local obstruction and, in later stages, from direct extension to adjacent organs (bladder, prostate, ureters, vagina, sacrum) and distant metastasis (usually liver). In the early stages, signs and symptoms are typically vague and depend on the anatomic location and function of the bowel segment containing the tumor. Later signs or symptoms usually include pallor, cachexia, asdtes, hepatomegaly, or lymphangiectasis.

On the right side of the colon (which absorbs water and electrolytes), early tumor growth causes no signs of obstruction because the tumor tends to grow along the bowel rather than surround the lumen, and the fecal content in this area is normally liquid. It may, however, cause black, tarry stools; anemia; and abdominal aching, pressure, or dull cramps. As the disease progresses, the patient develops weakness, fatigue, exertional dyspnea, vertigo and, eventually, diarrhea, obstipation, anorexia, weight loss, vomiting, and other signs or symptoms of intestinal obstruction.1n addition, a tumor on the right side may be palpable.

On the left side, a tumor causes signs of an obstruction even in early stages because stool consistency in this area is fonned. A tumor on the left side commonly causes rectal bleeding (in many cases ascribed to hemorrhoids), intermittent abdominal fullness or cramping, and rectal pressure. As the disease progresses, the patient develops obstipation, diarrhea, or "ribbon" or pencil-shaped stools. Typically, he notices that passage of a stool or flatus relieves the pain. At this stage, bleeding from the colon becomes obvious, with dark or bright red blood in the feces and mucus in or on the stools.

With a rectal tumor, the first symptom is a change in bowel habits, in many cases beginning with an urgent need to defecate on rising (morning diarrhea) or obstipation alternating with diarrhea. Other signs are blood or mucus in stool and a sense of incomplete evacuation. Late in the disease, pain begins as a feeling of rectal fullness that later becomes a dull,
and sometimes constant, ache confined to the rectum or sacral region.

Diagnosis information

Only a tumor biopsy can verify colorectal cancer, but other tests help detect it:

• Digital rectal examination can detect almost 15% of colorectal cancers. Hemoccult test (guaiac), also known as fecal occult blood test (FOBT), can detect blood in stools. This test is recommended yearly after age 50 for colorectal cancer screening and prevention.
• Proctoscopy or sigmoidoscopy can detect up to 66% of colorectal cancers. This test is reconunended every 5 years after age 50 for colorectal cancer screening and prevention.
• Colonoscopy permits visual inspection (and photographs) of the colon up to the ileocecal valve, and gives access for polypectomies and biopsies of suspected lesions. This test is the single most accurate test for detecting cancer or polyps. This test is reconunended every 10 years after age 50 for colorectal cancer screening.
• CT scan helps to detect areas affected by metastasis.
• Barium X-ray, using a dual contrast with air, can locate lesions that are undetectable manually or visually. Barium examination should follow endoscopy or excretory urography because the barium sulfate interferes with these tests. This test is recommended every 5 to 10 years for colorectal cancer screening beginning at age 50.
• Carcinoembryonic antigen, though not specific or sensitive enough for early diagnosis, is helpful in monitoring patients before and after treatment to detect metastasis or recurrence.

Treatment for Colorectal Cancer

The best treatment for colorectal cancer is prevention. Colorectal screening decreases the incidence of the disease by 75% to 90%. Other treatments recommended to prevent colorectal cancer include a diet:

• high in fruits and vegetables
• low in red and processed meats
• low in fat
• high in calcium and folic add.

A recent study found that women who took aspirin twice a week or more had a 44% reduction in risk after 20 years. The risk was also reduced in women who took a multivitamin with folic add for more than 15 years. However, it may take more than a decade for aspirin use to benefit and may cause gastric ulcers and hemorrhagic strokes. Thus, these aren't substitutes for regular colorectal cancer screening.

The most effective treatment once colorectal cancer is diagnosed is surgery to remove the malignant tumor and adjacent tissues and any lymph nodes that may contain cancer cells. The type of surgery depends on the location of the tumor:

• cecum and ascending colon - right hemicolectomy (for advanced disease), which may include resection of the terminal segment of the ileum, cecum, ascending colon, and right half of the transverse colon with corresponding mesentery
• proximal and middle transverse colon - right colectomy, which includes transverse colon and mesentery corresponding to midcolic vessels, or segmental resection of transverse colon and associated midcolic vessels
• sigmoid colon - surgery usually limited to sigmoid colon and mesentery
• upper rectum - anterior or low anterior resection, employing a newer method that uses a stapler and allows for resections much lower than were previously possible
• lower rectum - abdominoperineal resection and permanent sigmoid colostomy.

Chemotherapy is indicated for patients with metastasis, residual disease, or a recurrent inoperable tumor. Drugs used in such treatment commonly include fluorouracil with levamisole, leucovorin, methotrexate, or streptozocin. Patients. whose tumors have extended to regional lymph nodes may receive fluorouradl and levamisole for 1 year postoperatively.

Radiation therapy induces tumor regression and may be used before or after surgery or combined with chemotherapy, especially fluorouracil.

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SPECIAL NEEDS

Older patients may ignore bowel symptoms, believing that they result from constipation, poor diet, or hemorrhoids. Evaluate your older patient's responses to your questions carefully.

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Special considerations or prevention

Before surgery:

• Monitor the patient's diet modifications, laxatives, enemas, and antibiotics - all used to clean the bowel and to decrease abdominal, and perineal cavity contamination during surgery.
• If the patient is having a colostomy, teach the patient and her family about the procedure.
• Emphasize that the stoma will be red, moist, and swollen and that postoperative swelling will eventually subside.
• Show them a diagram of the intestine before and after surgery, stressing how much of the bowel will remain intact. Supplement your teaching with instructional aids. Arrange a post surgical visit from a recovered ostomate.
• Prepare the patient for postoperative I. V. infusions, nasogastric tube, and indwelling urinary catheter.
• Discuss the importance of cooperating during deep-breathing and coughing exercises.

After surgery:

• Explain to the patient's family the importance of their positive reactions to the patient's adjustment. Consult with an enterostomal therapist, if available, to help set up a regimen for the patient.
• Encourage the patient to look at the stoma and participate in its care as soon as possible. Teach good hygiene and skin care. Allow her to shower or bathe as soon as the incision heals. If appropriate, instruct the patient with a sigmoid colostomy to irrigate it as soon as possible after surgery. Schedule irrigation for the time of day when the person normally evacuated before surgery. Many patients find that irrigating every 1 to 3 days is necessary for regularity. If flatus, diarrhea, or constipation occurs, eliminate suspected causative foods from the patient's diet. Those foods may be reintroduced in the patient's diet later.
• After several months, many ostomates establish control with irrigation and no longer need to wear a pouch. A stoma cap or gauze sponge placed over the stoma protects it and absorbs mucoid secretions.
• Before achieving such control. the patient can resume physical activities, including sports, provided that there's no threat of injury to the stoma or surrounding abdominal muscles. However, caution the patient to avoid heavy lifting because herniation or prolapse may occur through weakened muscles in the abdominal wall. A structured and gradually progressive exercise program to strengthen abdominal muscles may be instituted under medical supervision.
• If appropriate, refer the patient to a home health agency for follow-up care and counseling. Suggest sexual counseling, especially after an abdominoperineal resection.
• Anyone who has had colorectal cancer is at increased risk for recurrence and should have yearly screening and testing.