TABLE 12-1 Overview of Gastrointestinal (GI) Malignancies | ||||||||||||||||||||||||||||||
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Gastrointestinal Cancers
Gastrointestinal Cancers
JoAnn Coleman
I. Gastrointestinal (GI) Cancers—An Overview
A. The GI tract has the highest incidence of malignant tumors.
1. Cancers of the GI tract include parts of the bowel lumen—gastric, colorectal, rectal cancers.
2. Cancers of the GI accessory organs—hepatic, biliary, bile duct, pancreas.
3. Although the esophagus is a part of the GI system, it is viewed and managed as a tumor of the head and neck region.
B. More than 25% of cancer deaths every year in the United States are attributed to cancer of the GI tract.
C. The problems common to all GI cancers stem from the delay in clinical presentation.
1. GI tumors proliferate insidiously and extend locally.
2. Presenting signs and symptoms may be misdiagnosed or self-treated for a long time.
3. As the tumor grows, it can exceed the distensible capacity of the GI lumen and result in obstruction.
D. Most tumors of the GI tract are adenocarcinomas.
E. The metastasis of GI tumors occurs by all three mechanisms of metastasis—local spread, blood vessel invasion, and dissemination through the lymphatic system. This diversity means these tumors metastasize to a large variety of sites outside the GI system.
F. Prognosis of the GI malignancy depends on:
1. Tumor type and site(s) of metastasis
2. Tumor size
3. Degree of cellular differentiation
4. Extent of metastases
5. Availability of effective treatments
6. Person’s general health
G. Diseases have very different prognostic implications and are treated as separate disease processes.
H. Table 12-1 provides an overview of the clinicopathophysiologic features of the GI malignancies (gastric cancer, hepatobiliary cancer, pancreatic cancer, colorectal cancer).
II. Etiology
A. Diseases have variable genetic, environmental, dietary risk factors.
B. Specific risk factors are discussed within Table 12-1.
III. Patient Management
A. Assessment (Specific assessment findings for each type of malignancy are included in Table 12-1.)
1. Patient history
a. Family history may be important in some of these disorders that are associated with familial genetic abnormalities (eg, colorectal cancer, pancreatic cancer).
b. Diet and social history may provide information about carcinogen exposure (eg, esophageal cancer, hepatic cancer) or known dietary risk factors.
c. History of infectious diseases. Viral illnesses or GI infections are known to predispose patients to certain GI malignancies (eg, hepatic cancer, gastric cancer, colorectal cancer).
2. Patient complaints
a. Most patients have subtle changes in eating or bowel habits that are largely ignored or attributed to other medical problems (eg, reflux, change in stool characteristics).
b. Abdominal pain is a common finding in many GI malignancies, although the localization of pain differs with each of the disorders.
(1) Pain localization may be helpful in determining the area of the GI tract that is affected.
(2) Low back pain or epigastric/substernal pain may also represent GI disease.
(3) Pain that is “rebound” or worse with lifting the hand rather than pressing downward signals an acute abdominal crisis and possible surgical candidate.
c. Bleeding from the GI tract is a cardinal symptom of malignancy. Any blood, such as old blood in emesis or stool, or smearing of blood on defecation is important to evaluate for the presence of malignancy.
3. Physical findings
a. All patients with suspected GI malignancy should have a thorough abdominal assessment.
(1) Bowel contours, bulges, pulsations
(2) Bowel sounds for abnormalities
(3) Light and deep palpation for areas of tenderness or masses
b. Signs of abnormal fluid balance, nutrition, and metabolic regulation are common with all GI malignancies.
(1) Dehydration and orthostasis occur due to fluid shifts into the peritoneal space when inflammation is present.
(2) Nutrient absorption is often compromised before a diagnosis of malignancy is made. Symptoms may include dry, flaky skin; taste changes; alopecia; oral tenderness; bruising.
(3) Symptoms may relate to the degree of constipation or diarrhea the patient has experienced.
B. Diagnostic Tests (Unique and specific diagnostic tests for each type of GI malignancy are included in Table 12-1.)
1. Screening guidelines. The only GI cancer for which there are screening guidelines for early detection is colorectal cancer. Colorectal cancer detected in its early stages has an excellent prognosis, and screening tests are adequately sensitive and specific to provide this information. Controversy exists regarding the age at which to start screening (40 versus 50 years of age), best test, and frequency of testing. These guidelines are the recommendations of the Centers for Disease Control (CDC, 2002).
a. For healthy people starting at age 50 years without significant risk factors (see III.B.1.b for description of significant risk factors.)
(1) Fecal occult blood test yearly AND
(2) Flexible sigmoidoscopy or double contrast barium enema once every 5 years
(3) Some advise a colonoscopy every 10 years after age 50 years for a more thorough inspection for polyps or suspicious lesions, but insurance reimbursement for this may be limited.
b. For people at any age with a significant risk factor (immediate family member with colorectal polyps or cancer, or a personal history of inflammatory bowel disease)
(1) Fecal occult blood test and flexible sigmoidoscopy annually OR
(2) Colonoscopy every year
c. For anyone with abnormal basic screening tests, the usual gold standard for follow-up assessment and detection of polyps or GI tumors is the colonoscopy.
2. Laboratory tests. Few laboratory tests are exclusively diagnostic for any GI malignancy, although some tests that may be ordered for diagnosis or monitoring of response to treatment may include tests for:
a. Genetic abnormalities
b. Tumor markers
c. Serum comprehensive chemistry profile, hepatic panel
3. Evaluation for potential GI malignancy often involves radiologic procedures (x-rays, computed tomography [CT] scans) to detect masses.
4. Many patients will also require an endoscopic procedure to visualize and possibly obtain a histopathologic specimen for diagnosis.
C. Treatment is individualized for patients depending on their clinical stage and type of disease. An overview of treatment options is provided in Tables 12-1, 12-2, 12-3, 12-4, 12-5, 12-6, 12-7 and 12-8. Basic concepts of treatment planning for patients with GI malignancies include the following:
