Week 12: Chp 58: Colorectal Cancer Flashcards
Colorectal cancer involves cancer of what?
cancer of the rectum and large intestine
-mostly found in the distal portion of the large intestine
Risk Factors
personal or family history of colorectal cancer (first-degree relative), history of adenomatous polyps, inflammatory bowel disease (IBD) for 10 years or more, familial adenomatous polyposis, hereditary non-polyposis colorectal cancer (HNPCC) or lynch syndrome, physical inactivity, obesity, high-fat diets and consumption of red meat (> 7 servings per week), and processed meats, cigarette use, and alcohol intake (> four drinks per week)
- inadequate intake of fruits and vegetables
- diabetes type 2
- industrialized countries
- increases with age
What type of cancer is colorectal cancer?
adenocarcinomas
-type of cancer that originates in glandular cells of internal organs
Where can colorectal cancer metastasize to?
liver
-lungs, brain, bones, and adrenal glands
Seeding
may also occur during resection when the cancer cells break off from the tumor into the peritoneal cavity
Diagnostic Studies for Colorectal Cancer
Fecal occult blood test (FOBT), or fecal immunochemical test (FIT) and digital rectal examination (DRE)
- Lower GI series
- double-contrast barium enema
- sigmoidoscopy
- colonoscopy
- virtual colonoscopy
- fecal DNA testing
- wireless capsule endoscopy
Fecal Occult Blood Test (FOBT), or Fecal immunochemical Test (FIT), and digital rectal examination (DRE)
stool sample is collected and placed on a special slide and tested for hidden blood
-a DRE is performed by the provider
Lower GI series
a tube is inserted into the rectum, and the large intestine is filled with barium
- the patient is asked to change positions several times in order to evenly distribute the barium
- x-ray pictures and/or video are taken
- the barium is constipating, so care should be taken to advise the patient to take appropriate measures to prevent constipation
Double-contrast barium enema
takes place after the patient has expelled most of the barium from the intestine
-the remaining barium clings to the intestinal wall; the intestine is then inflated with air, and additional x-ray images are taken
Sigmoidoscopy
a flexible tube with a light and camera at the end is inserted into the rectum and colon up to the transverse colon
- the camera transmits images to the computer screen
- biopsies can be taken from the rectum and sigmoid colon for further examination
Colonoscopy
a long, flexible tube with a light and camera on the end is inserted into the full length of the colon
- the provider has the ability to view the entire colon as well as to remove polyps and take biopsies as deemed necessary
- the patient receives sedation for the procedure
Virtual Colonoscopy
performed in either the CT scanning department or MRI
-a tube is inserted into the rectum
-for CT, carbon dioxide is administered to enlarge the colon for better viewing
for MRI, a contrast medium is given through the rectum to expand the large intestine
-cross-sectional images are produced and processed to create three-dimensional, computer-generated images of the large intestine
-sedation is not required
Fecal DNA testing
colorectal cancers contain abnormal DNA that is shed in the stool
-if this test is positive, it should be followed with a colonoscopy
Wireless Capsule endoscopy
“pill camera”
- a pill approximately the size of a vitamin; patient swallows the pill with the camera within the pill, and the camera captures videos through the GI tract
- takes 8 hours to pass through the GI tract while images are recorded on a portable device
- images transported from device to computer
- technique most useful with cancers of the small bowel that are difficult to detect through traditional endoscopy
Clinical Manifestations
early stage, symptoms are insidious and go ignored by patient
- vary according to where the cancer is located in the intestine
- first signs: unexplained weight loss and fatigue
- change in bowel regularity and/ or appearance of stool, blood in the stool (red or black depending on location), abdominal pain and/or distension, and a sensation of pressure as with incomplete evacuation after a bowel movement, along with clinical manifestations of anemia
Clinical Manifestations regarding ascending colon
vague abdominal pain and/or cramping, change in bowel habits, anemia (not enough healthy red blood cells), and fatigue
Clinical manifestations regarding transverse colon
pain, clinical manifestations of obstruction, change in bowel habits, anemia, fatigue
Clinical manifestations regarding descending colon
pain, change in bowel habits, bright red blood in stool, and clinical manifestations of intestinal obstruction
Clinical manifestations regarding cancer in rectum
blood in stool, change in bowel habits, rectal discomfort, and feeling of incomplete evacuation
Gold Standard for diagnosing Colorectal Cancer
colonoscopy
Use of Colonoscopy
biopsies can be taken, and polyps removed during the procedure
Colonoscopy and what other diagnostic studies may be evaluated with colorectal cancer?
- serum carcinoembryonic antigen (CEA)
- CBC
- CT
- MRI
- abdominal x-rays
an elevated serum carcinoembryonic antigen (CEA) indicates what?
overexpression of an oncofetal glycoprotein that is normally expressed by mucosal cells
CBC results may demonstrate what?
anemia due to blood loss and an elevated WBC secondary to inflammation and infection
CT, MRI, and abdominal x-rays may indicate what?
information about abdominal obstruction
Common method for staging colorectal cancer
TNM (tumor-node-metastasis) classification system
- stages I through IV
- prognosis worsens with larger size and depth of tumor, lymph node involvement, and metastasis
Treatment
- chemotherapy
- radiation therapy
Treatment: Chemotherapy
used as an adjunct to improve survival rates for patients whose tumors cannot be completely removed
- adjuvant chemotherapy for stage II and III
- chemotherapy interrupts DNA production of cells
- cannot distinguish between healthy cells and cancer cells
- intra-arterial chemotherapy may be given into the liver if metastasis has occurred
Side effects of chemotherapy
- diarrhea
- mucositis
- leukopenia
- mouth ulcers
- alopecia
- peripheral neuropathies