Colorectal Cancer

Alabama Nurse, Dec 2004-Feb 2005 by Van Gerpen, Ruth

Objectives: At the conclusion of this activity the participant should be able to:

1. Identify risk factors for colorectal cancer.

2. State the screening recommendations for individuals at average risk.

3. Differentiate clinical presentation of colorectal cancer based on tumor location.

4. Identify treatment modalities for colon and rectal cancer.

5. Describe quality of life issues for individuals with colorectal cancer.

Directions: Read the article carefully. Return the answer sheet (or a copy) printed at the end of the article and fill out all sections carefully. Mail to the address provided with the appropriate fee. Certificates will be mailed upon successful completion of both the post-test and evaluation. You must score at least 70% to pass. Should you fail the test you will be notified and offered an opportunity to retake the test. All retakes will require an additional fee.

Contact Hour and Accreditation: This 1.4 contact hour activity has been approved by the North Dakota Nurses Association which is has been accredited as an approver of continuing education in nursing by the American Nurses Credentialing Center (ANCC). Contact hours are valid through August 15, 2005.

Colorectal Cancer

Colorectal cancer is the third most common cancer in men and women in the United States. Despite awareness about risk factors and primary and secondary prevention, it remains the second most frequent cause of cancer deaths. Because colorectal cancer often shows few symptoms until the advanced stages of the disease, nurses can play a pivotal role in identifying patients at risk, providing information and promoting screening and early detection tests to decrease mortality and morbidity.

Incidence

Americans have about a 5.9 % lifetime risk of being diagnosed with colorectal cancer, with the incidence increasing significantly beginning at 40 years of age. In 2003, an estimated 147,500 new cases of colorectal cancer will be diagnosed and approximately 57,100 deaths will occur in the United States. In Nebraska, 1,100 new cases of colorectal cancer will be diagnosed and 400 deaths will occur (Jemal et al, 2003). The overall incidence of colorectal cancer is similar for both men and women, however rectal cancer occurs more often in men than in women. The incidence is higher in industrialized regions such as North America, Europe and Australia than in Asia, Africa, and South America (Saddler & Ellis, 1999).

The incidence also varies significantly by race and ethnicity. In blacks, the incidence of colorectal cancer has increased by 30% since 1973 and is higher than in whites (Pazdur, 1999). Incidence in the Alaska Natives population is over four times as high as rates in the American Indian population (New Mexico) for both men and women. After Alaska Natives, the next highest rates are among the Japanese, black and non-Hispanic white populations. These are followed by Chinese, Hawaiians, and white Hispanics; and then Filipinos, Koreans and Vietnamese. In each racial/ethnic group, incidence rates for cancers of the colon and rectum among women are lower than those among men (National Cancer Institute, 1996).

Mortality patterns by race and ethnicity are similar to those for incidence. However, the mortality rates among white non-Hispanic and black men and women, and among Hawaiian men, appear disproportionately high (National Cancer Institute, 1996). The differences in incidence rates among various races and ethnic groups may be explained by lifestyle or environmental factors, especially diet and exercise. Several studies have shown that migrants to the United States from Japan and other countries where rates of colorectal cancer are lower than in the U.S. have higher rates than those who remain in their native country. Also, first and second generation American offspring from these migrant groups develop these cancers at rates reaching or exceeding those of the white population in the United States (National Cancer Institute, 1996).

Risk Factors

The specific causes of colorectal cancer are unknown, however a number of factors are associated with an increased risk of developing colorectal cancer (Table 1).

Age

As with most malignancies, the development of colorectal cancer is associated with aging. The risk of developing colorectal tumors becomes significant starting at age 40 and increasing until the eighth decade. More than 90% of individuals are over the age of 50 at the time of diagnosis (Ries et al., 2000).

Diet

Both national and international studies have shown a clear association between colorectal cancer and specific dietary habits. The Western diet, known for being high in fat, cholesterol and red meat, and lower in fruits, vegetables and fiber content, has been linked to an increased risk of colorectal tumors. People living in the industrialized countries in North America, Northwestern Europe and Australia frequently consume this type of diet. Animal fats and cholesterol contribute to the production of secondary bile acids, which exerts a carcinogenic effect. Fiber is an important dietary component because it decreases the contact time of carcinogenic substances with the mucosa in the bowel (Wynder, Reddy & Weisburger, 1992).