Posted: September 10th, 2021

Colorectal Cancer Risk Factors and Screening

Disorders of Gastrointestinal Function: Colorectal Cancer Risk Factors and Screening

Colorectal cancer (CRC) remains a significant health concern worldwide, with dietary choices playing a crucial role in its development and progression. This paper examines the case of Marcee, a 52-year-old woman diagnosed with stage I colorectal cancer, focusing on the potential dietary risk factors, the development of adenomatous polyps, and the importance of screening methods such as the fecal occult blood test.

Dietary Risk Factors in Colorectal Cancer Development

Marcee’s dietary habits, characterized by a reliance on vending machine foods and prepackaged meals, raise several concerns regarding her risk for colorectal cancer. Recent studies have highlighted the significant impact of diet on CRC risk. A comprehensive analysis by Jin et al. (2023) found that higher intakes of dietary fiber, magnesium, phosphorus, and manganese were associated with a lower risk of CRC. Conversely, alcohol consumption was linked to an increased risk (Jin et al., 2023).

Marcee’s preference for processed and convenience foods likely results in a diet low in fiber and essential nutrients. Celiberto et al. (2023) emphasized that inadequate dietary fiber intake, endemic in Western countries, could be a driving factor in the increasing incidence of CRC. Furthermore, a study by Wang et al. (2022) detected a positive association between ultra-processed food consumption and CRC risk, particularly in men.

The lack of fresh fruits and vegetables in Marcee’s diet is also concerning. Zhang et al. (2024) indicated that fresh fruit intake was associated with a decreased risk of CRC. Additionally, Veettil et al. (2021) highlighted the importance of modifiable lifestyle factors, including diet and physical activity, in CRC prevention.

Development and Histologic Features of Adenomatous Polyps

Adenomatous polyps are precursor lesions for the majority of colorectal cancers. These polyps develop through a series of genetic and epigenetic alterations, known as the adenoma-carcinoma sequence. Histologically, adenomatous polyps are characterized by dysplastic epithelium, with abnormal cell proliferation and architecture (Fearon & Vogelstein, 1990).

The progression from normal mucosa to adenoma and eventually to carcinoma involves several key genetic mutations. These typically include alterations in the APC gene (initiating the polyp formation), KRAS mutations (promoting growth), and p53 mutations (allowing for malignant transformation) (Vogelstein et al., 1988).

Histologically, adenomatous polyps can be classified into three subtypes: tubular, villous, and tubulovillous. Tubular adenomas are the most common, characterized by branching tubules. Villous adenomas have finger-like projections, while tubulovillous adenomas show a mixture of both patterns. The risk of malignant transformation increases with polyp size and villous component (Muto et al., 1975).

Pseudopolyps in Ulcerative Colitis

Pseudopolyps, seen in ulcerative colitis, differ significantly from adenomatous polyps. These lesions are not precancerous and form as a result of the chronic inflammation and ulceration characteristic of ulcerative colitis. Pseudopolyps represent islands of regenerating mucosa surrounded by ulcerated areas (Choi & Appelman, 2017).

Unlike adenomatous polyps, pseudopolyps do not show dysplastic changes. Histologically, they consist of normal or hyperplastic mucosa, often with a prominent inflammatory component. While pseudopolyps themselves are not precancerous, their presence indicates severe, longstanding inflammation, which is a risk factor for CRC development in ulcerative colitis patients (Choi & Appelman, 2017).

Fecal Occult Blood Test as a Screening Tool

The fecal occult blood test (FOBT) is an important screening tool for colorectal cancer due to its ability to detect small amounts of blood in the stool, which may be indicative of colorectal neoplasia. This test is based on the principle that colorectal tumors or large adenomas may bleed intermittently, often unnoticeably to the patient (Allison et al., 2014).

The procedure for administering the FOBT typically involves the following steps:

Patient preparation: The patient is instructed to avoid certain foods and medications that may interfere with the test results for several days before the test.

Sample collection: The patient collects small stool samples from two or three separate bowel movements.

Sample application: The stool samples are applied to special cards or tubes provided in the test kit.

Laboratory analysis: The samples are sent to a laboratory where they are analyzed for the presence of blood using either guaiac-based or immunochemical methods.

Result interpretation: A positive result indicates the presence of blood in the stool and warrants further investigation, typically through colonoscopy (Allison et al., 2014).

The FOBT is valuable as a non-invasive, cost-effective screening method that can be easily performed at home. However, it’s important to note that a positive result does not definitively diagnose cancer, as other conditions can cause blood in the stool. Conversely, a negative result does not guarantee the absence of cancer, as bleeding can be intermittent (Allison et al., 2014).

In conclusion, Marcee’s case highlights the importance of dietary choices in colorectal cancer risk. Her reliance on processed foods likely contributed to an increased risk profile. Understanding the development of adenomatous polyps, distinguishing them from pseudopolyps, and utilizing screening tools like the FOBT are crucial in the early detection and management of colorectal cancer. Regular screening, coupled with dietary modifications towards a more fiber-rich, nutrient-dense diet, could significantly reduce the risk of CRC development and improve outcomes for patients like Marcee.

References:

Allison, J. E., Fraser, C. G., Halloran, S. P., & Young, G. P. (2014). Population screening for colorectal cancer means getting FIT: the past, present, and future of colorectal cancer screening using the fecal immunochemical test for hemoglobin (FIT). Gut and Liver, 8(2), 117-130.

Celiberto, F., Grazioli, F., Lenti, M. V., & Di Sabatino, A. (2023). Fibres and Colorectal Cancer: Clinical and Molecular Mechanisms. Nutrients, 15(18), 3984.

Choi, C. H., & Appelman, H. D. (2017). Pseudopolyps in inflammatory bowel disease. Surgical Pathology Clinics, 10(4), 887-898.

Jin, D., Zhang, X., Luo, Y., & Song, Y. (2023). Diet-Wide Association, Genetic Susceptibility and Colorectal Cancer Risk: A Large Prospective Cohort Study. Nutrients, 15(22), 4801.

Wang, L., Du, M., Wang, K., Khandpur, N., Rossato, S. L., Drouin-Chartier, J. P., … & Zhang, F. F. (2022). Association of ultra-processed food consumption with colorectal cancer risk among men and women: results from three prospective US cohort studies. BMJ, 378.

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Disorders of Gastrointestinal Function.
Marcee 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 (Chapter 37, Learning Objective 9).

Review Marcee’s 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.
Instructions:

Your primary post should be at least 200 words long and should include reference to the textbook or another course resource using APA 7th edition format. Your primary post is due by Wednesday at midnight ET.
Respond with at least 100 words (each) to at least two classmates’ posts by Sunday at midnight ET.

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Tags: Adenomatous polyps, Colorectal Cancer, Dietary risk factors, Fecal occult blood test