Work on the case studies below
In your discussion, be sure to evaluate the presence and effects of alterations in the homeostatic state secondary to gender, genetic, ethnic, and temporal variables.
Case Study 5: Disorders of Gastrointestinal FunctionMarcee is a 52-year-old woman who worked at a reception desk at a company head office. She took some time off when she was treated for colorectal cancer. The Dukes classification was stage I, and the treatment protocol involved surgery and radiation therapy. No one in her family had a history of the disease. Marcee does not drink or smoke, but she does not pay close attention to her diet. At work, her meals consisted mainly of the foods she got from vending machines at the cafeteria. At home, she preferred to heat up frozen dinners or any prepackaged food that required minimal preparation time.
Review Marcees diet. What factors in her dietary choices might contribute to the development of colorectal cancer?
Colorectal cancer often arises from adenomatous polyps. What are the development and histologic features of these polyps?
Colorectal cancer may be a complication in individuals with ulcerative colitis. How are the pseudopolyps seen in this disease different from the polyps discussed above?
Why is a fecal occult blood test used as one of the screening tools for colorectal cancer? Explain the procedure for administering the test.
Case Study Evaluation: Disorders of Gastrointestinal Function in Colorectal Cancer
Review of Marcee's Diet
Marcee’s diet, characterized by convenience foods such as vending machine snacks and prepackaged frozen dinners, may contribute to her increased risk for colorectal cancer due to several factors:
1. Low Fiber Intake: Many processed foods lack dietary fiber, which is essential for promoting regular bowel movements and maintaining healthy gut flora. Low fiber intake is associated with a higher risk of developing colorectal cancer as it can lead to constipation and prolonged exposure of the intestinal lining to potential carcinogens.
2. High Saturated Fats and Low Nutrient Density: Prepackaged meals often contain high levels of saturated fats and low levels of essential vitamins and minerals. Diets high in red and processed meats have been linked to an increased risk of colorectal cancer, potentially due to the presence of harmful compounds formed during cooking.
3. Insufficient Fruit and Vegetable Consumption: A diet lacking in fruits and vegetables limits the intake of antioxidants, vitamins, and phytochemicals that can protect against cancer through their anti-inflammatory properties and their ability to reduce oxidative stress.
4. Sedentary Lifestyle: While not directly a dietary factor, Marcee’s work environment may contribute to a sedentary lifestyle. Lack of physical activity is a known risk factor for colorectal cancer.
Development and Histologic Features of Adenomatous Polyps
Adenomatous polyps are benign growths that can develop in the colon and are precursors to colorectal cancer. Their development involves several key processes:
1. Dysplastic Changes: Adenomatous polyps arise from the epithelial cells lining the colon, undergoing dysplastic changes due to genetic mutations that affect cell growth and differentiation.
2. Histological Features:
- Tubular Adenomas: These are the most common type, characterized by tubular structures with a central lumen lined by dysplastic epithelium.
- Tubulovillous Adenomas: These polyps exhibit features of both tubular and villous adenomas. They have a greater risk of progression to cancer than tubular adenomas.
- Villous Adenomas: These are characterized by finger-like projections (villi) and have the highest risk of malignant transformation, often exceeding 30%.
The progression from adenomatous polyp to colorectal cancer is a gradual process known as the adenoma-carcinoma sequence.
Differences between Pseudopolyps in Ulcerative Colitis and Adenomatous Polyps
Pseudopolyps seen in ulcerative colitis differ significantly from adenomatous polyps:
1. Nature of Formation: Pseudopolyps are inflammatory lesions resulting from the healing process after ulceration in ulcerative colitis. They are not true neoplastic growths but rather represent areas of regenerating mucosa amidst areas of inflammation.
2. Histological Features: Pseudopolyps typically show areas of ulceration, inflammation, and fibrosis, with no dysplastic epithelial changes associated with neoplastic growth. In contrast, adenomatous polyps exhibit dysplasia indicative of potential malignancy.
3. Malignant Potential: Pseudopolyps generally do not have malignant potential, whereas adenomatous polyps can progress to colorectal cancer if left untreated.
Fecal Occult Blood Test (FOBT) for Colorectal Cancer Screening
The fecal occult blood test is used as a screening tool for colorectal cancer because it detects hidden blood in the stool, which may indicate the presence of polyps or tumors:
1. Significance of FOBT: The presence of blood in stool can be an early indicator of colorectal cancer or significant adenomatous polyps, making early detection possible before symptoms arise.
Procedure for Administering FOBT
1. Sample Collection: Patients are typically instructed to collect stool samples from different bowel movements over several days. They often use special collection kits provided by healthcare providers.
2. Application to Test Cards: The collected stool samples are applied to test cards or slides that contain chemicals that react with hemoglobin in blood.
3. Processing: After application, the test cards are sent to a laboratory or processed according to specific guidelines provided with the kit.
4. Interpretation: A positive test result would indicate the presence of blood in the stool, warranting further investigation through colonoscopy or additional imaging studies to determine the cause.
Conclusion
Marcee's dietary choices highlight important risk factors for colorectal cancer. Understanding the development and histological characteristics of adenomatous polyps versus pseudopolyps in ulcerative colitis emphasizes the need for surveillance in at-risk populations. Utilizing tools like the fecal occult blood test enhances early detection efforts, ultimately improving outcomes in colorectal cancer management.
References
- American Cancer Society. (2021). Colorectal Cancer: Early Detection. Retrieved from ACS.
- Winawer, S. J., Zauber, A. G., & O'Brien, M. J. (2006). Colorectal Cancer Screening. The American Journal of Gastroenterology, 101(3), 517-526.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). (2017). Adenomatous Polyps. Retrieved from NIDDK.